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83 auto acceleration woes 🤔

Old 12-20-2018, 09:16 PM
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83 auto acceleration woes 🤔

Hey yíall, Iíve got a 1983 pickup with a 22r and auto trans. Iím having this problem where when I accelerate from a stop the truck either dies or hesitates for a second and then lurches forward pretty hard and goes. If I slam on the gas everytime I want to accelerate from a stop it doesnít stall but I go faster than Iíd like to. I canít barely give it gas to go slow. This can be pretty stressful when Iím in traffic or parallel parking. Itís worse as the truck heats up.

Ive recently replaced the distributor cap and plugs, fuel level is good in the sightglass, I checked timing and I tested the egr and egr modulator according to the fsm. Truck does have a small leak in the muffler. Any help is appreciated!
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Old 12-21-2018, 05:28 AM
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Gotta be in the carburetor. I'm not an Aisin carb expert, but I expect there's something akin to an accelerator pump in the Aisin carb where the diaphragm has sprung a leak and doesn't work right any more. I'd recommend replacing the Aisin with a Weber 32/36, but I see you're in California and the smog police may look unfavorably on that swap. But, LCE has a Weber that they say is smog compatible (?). Of course, you can work on that Aisin carb, or have someone else try to fix it. Good luck. Let us know how this turns out please.
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Old 12-21-2018, 05:53 AM
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I agree with rick, with age the accelerator pump gets stiff and cracks, not allowing for smooth acceleration/de-acceleration.
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Old 12-21-2018, 09:07 AM
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Thanks for getting back, I forgot to mention that I replaced the carb about a month ago with a rebuilt aisin toy 505 from national carburetors. It seems unlikely to me that the aap could go so fast? The original carb had the same symptoms along with a lot more ;-). I’m going to check the fsm to see what makes the aap function

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Old 12-21-2018, 10:29 AM
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Took a peek in there to see if the vacuum lines to the aap were hooked up correctly and they are. Also confirmed that the choke heater is working.

My understanding of the AAP is that it provides extra fuel when the engine is cold and then stops when the engine is warm. My problem worsens as the engine heats up. I'm starting think this could be more of a choke issue but still pretty confused over here.

Last edited by northoak; 12-21-2018 at 02:08 PM.
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Old 12-24-2018, 08:52 AM
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Could be the Vacuum Switching Valve that controls the AAP. It's usually screwed into the intake manifold & operates on the coolant temperature, open when cold providing vacuum to the AAP, closed when hot, cutting off vacuum to the AAP. If it's not closing when hot it's providing vacuum to the AAP, making your mixture too rich, which could cause the stumbling. Tromping the pedal opens up the butterfly in the carb more, giving it more air, & leaning down the mix. To test the valve you'd need to put a vacuum gauge on the valve port, start the engine cold, then watch the gauge as it warms up.
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Old 12-24-2018, 11:14 PM
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Originally Posted by 13Swords View Post
Could be the Vacuum Switching Valve that controls the AAP. It's usually screwed into the intake manifold & operates on the coolant temperature, open when cold providing vacuum to the AAP, closed when hot, cutting off vacuum to the AAP. If it's not closing when hot it's providing vacuum to the AAP, making your mixture too rich, which could cause the stumbling. Tromping the pedal opens up the butterfly in the carb more, giving it more air, & leaning down the mix. To test the valve you'd need to put a vacuum gauge on the valve port, start the engine cold, then watch the gauge as it warms up.
Thanks for the tip. Im in southern californina visiting family and I must say that these issues make the traffic extra stressful.

I just replaced the EGR valve and confirmed that the other one was pretty dirty and partially clogged but it did not solve the problem. I also confirmed that the choke is fully opening.

The truck doesn't stall anymore but it still hesitates/bucks when accelerating. Sounds like its possibly misfiring/poping at times. Will Test te VSV and report back but any other suggestions are appreciated.
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Old 12-25-2018, 08:56 AM
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Originally Posted by northoak View Post
Thanks for the tip. Im in southern californina visiting family and I must say that these issues make the traffic extra stressful.

I just replaced the EGR valve and confirmed that the other one was pretty dirty and partially clogged but it did not solve the problem. I also confirmed that the choke is fully opening.

The truck doesn't stall anymore but it still hesitates/bucks when accelerating. Sounds like its possibly misfiring/poping at times. Will Test te VSV and report back but any other suggestions are appreciated.
You are most welcome. Considering what you have already done, and if it turns out that the VSV is functioning the way it should, here are some other ideas/things that could be causing the problem.

Fuel Delivery Issues -

1. Weak or malfunctioning fuel pump. The diaphragm in the mechanical fuel pump (which the '83 22R carb'ed should have) over time can get stiff, weak, develop pinholes, tear, rupture or just plain deteriorate, causing reduced fuel pressure & volume. Also if you are running today's typical 10% Ethanol gas in the truck, the ethanol may cause these problems on internal rubber parts, like the diaphragm. If your current pump has been installed for 8-10 years or more, or more than 100,000 miles, it's likely wise to get a new one in it. New ones have ethanol compatible diaphragms in them. They are also easy to replace & shouldn't cost you more than $40 at any parts store. Just make sure you reuse your old pump spacer (if it's in good shape) or use a new one (some new pumps come with a new spacer & gaskets).

2. Rubber fuel Lines. Loose connections could be leaking fuel or drawing air in, resulting in lower fuel pressure & volume. Dry rotted, cracked or pin-holed lines, same problem. Lines should be pliable; if stiff they should be replaced with new. The lines could also be deteriorated internally due to ethanol. Older rubber isn't formulated to handle ethanol so if they are older lines, this could be a problem. Small particles of rubber can come off the inside walls of the lines & clog up the carb's float valve, idle or main jets, carb internal passages, or fuel filter.
The lines take time to replace & it isn't too hard, the exception being the lines near the tank. Usually dropping the tank is the best way to do it, but that's some work. The rubber line itself is cheap, usually $2 a foot & again, the new stuff is ethanol compatible. I'd also get all new hose clamps of the proper size while I was at it. I recommend the "spring type" with the "ears" for fuel lines over the "radiator type" clamps with the screw in them. Rubber hose will shrink over time, & the spring clamps will self-adjust to that, keeping constant tension on the hose end, preventing any leaks.

BTW, I also replaced my carb with one from National Carburetor. No worries about the ethanol there, as they use the proper ethanol compatible parts in their rebuilds. National is great at what they do.

3. Fuel Filter. You didn't mention if you have replaced it or not. Could be clogged, restricted, contaminated or just plain old & not doing it's job right. Again, an easy replacement & usually about $5. Also easy to do if you are doing the rubber lines at the same time.

Misfiring/Popping - This can be due to a mechanical or electrical problem in the ignition system, or a malfunctioning part.

1. You said you replaced the distributor cap & spark plugs, but what about the rotor & wires? Best to have all that stuff replaced at the same time, so you know they are OK, & eliminate them as causes. Gives you a good baseline for diagnosing any problems.
Did you check/set the gap on the spark plugs when you installed them? Gap should be .031" I never trust the gap straight out of the box. I've even seen one out of the box that was closed entirely, effectively shorting out the plug resulting in no spark. That won't run well. :^)
Make sure all spark plug wires are fully seated on the plugs (you should hear a "click") & in the distributor cap terminals (no "click" here). They can look like they are connected, but aren't. This would cause a misfire because the electricity isn't getting to one or more spark plugs. Also check that coil to distributor wire is properly connected.

2. Distributor. Vacuum Advance hooked up correctly? Check the vacuum diagram under the hood, find the diagram online or check the repair manual (if you have one). The 22R vacuum advance usually has 2 hoses going to it & swapping these around will cause problems.
Vacuum Advance working? Mechanical advance working? Sometimes the advancing weights in the distributor can get stuck or a return spring can break or come off the weight.
Take off the cap & rotor & look down into the distributor to see if the springs are there. You can gently push each weight (there are 2) outward to see if they move smoothly. If they don't you can clean the pivot points with WD-40 or similar, dry it off, & put a drop or two of light oil (like 3-in-1 oil) on the pivots. That usually fixes it.
Also the distributor could be worn itself, which will affect your timing, & could be a cause of stumble.
Timing been checked? It should be 5 degrees before top dead center (BTDC).

3. Ignition Coil. Has the coil been tested to see if the primary & secondary resistances are in spec? A coil that's going bad could cause your issue. Connections to coil clean & tight? Dirty connections give less power to the coil (due to resistance), & sometimes could even cause an intermittent condition under low load, that goes away under higher load.

That's enough to check for now. There are some other things that could cause the problem but are are more involved, but it's always best to check the simple things first. 8 times out of 10 it's something not that complicated. The only problem with older vehicles like ours is that there can be several simple things happening at once, which just makes it seem complicated. Just take your time & go thru it one thing at a time, you'll find it & fix it eventually. Meanwhile have a nice holiday & visit with your family. Post any progress when you have it, I'll be around.
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Old 12-25-2018, 12:15 PM
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Thanks again, I snuck out this morning to mess with it.

0. Tested the BVSV by hooking my vacuum pump inline between it and the AAP. It read about 15 psi. I let the it sit four about 30 minutes checking up on it periodically and it stayed around 15 the entire time. Seems like it is continuing to provide vacuum to the AAP like you suggested.

Here is the confusing thing. I went ahead and plugged the line to the AAP after to see if the truck would stop hesitating once that vacuum was removed and the problem persisted. In theory wouldn't the problem go away once vacuum was removed to the AAP? I'm also confused because the problem is there when the engine is cool as well. I imagine it should function properly until it warms up if the valve is not closing when hot?

1. Rotor and wires are about 6 months old and replaced by the previous owner. I replaced the plugs about a week ago and gapped them.

2. I tested the vacuum advance according to the fsm and it all checked out by their standards. I'll get back in there to make sure those springs are moving smoothly

3. I replaced the coil when I was chasing down a charging issue about a month ago that ended up being a bad voltage regulator. I assume it checks out since its new but that may be foolish. I also manged to clean the contact points where it bolts to the frame/ground wire.

Fuel pump and filter are only a few month old. Can I rule out fuel issues if the level is pretty much always halfway in the carb sight glass even after it stalls?

I think the next things on my list are: replace 3 port bvsv (if anyone knows a cheap source for one please let me know), oil pivot points in distributor, replace rubber fuel lines and check contacts for my coil plug. I'm not seeing anything for trouble shooting the accelerator able linkage but am wondering if its something simple in there is contributing. I noticed the shaft that goes from the accelerator cable down to the actual throttle arm is adjustable in length but haven't found any info on adjusting that.

thanks again for all the help! happy holidays.

Last edited by northoak; 12-25-2018 at 06:06 PM.
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Old 12-26-2018, 06:53 AM
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OK, I may have to apologize to you, as it seems I may not have been clear enough about testing the BVSV. If I am reading what you are saying here correctly, You tested the BVSV with your vacuum pump, pumped up the vacuum, & it held vacuum over time. Am I correct? That's actually not what I was trying to suggest as a test for the BVSV. The valve may actually hold vacuum but still be faulty. The way you tested it doesn't test the actual actuating part of the valve, which responds to heat, & actually controls the flow of vacuum to the AAP. What I was suggesting was putting the vacuum gauge in line like you said, but running the engine from cold to completely warmed up, all the time watching the gauge to see what it will do. The "B" in BVSV stands for "Bi-Metal". Bimetal refers to an object that is composed of two separate metals joined together. The metals have different rates of expansion & contraction when heated or cooled. Your BVSV is normally open, that is, provides vacuum to the AAP when cold. As the engine heats up, the bimetal heats up & expands, slowly closing the valve, to a point at full operating temperature where it completely shuts off the vacuum to the AAP.

The carb choke works on the same principle. There is a coiled bimetal spring in the choke housing that is attached to the choke valve in the top of the carb. Yours should be electric; mine (20R) is controlled by coolant temp. There is an electric heating element in the choke housing that heats the spring when the truck is running.

Long story short, you have to actually provide engine heat to the BVSV to fully test it. Vac gauge should read vacuum when cold, but slowly drop as the engine heats up, & should read no vacuum by the time the engine is fully warmed up. That's the only way to know if the valve is providing vacuum to the AAP at the right times or not.

Your plugging the vac line to the AAP was a good idea. It completely removes the AAP from the system. Sibe you had no change in run quality with it plugged, we can safely assume your problem isn't in the AAP itself. It's also likely that the BVSV is good as well, but go ahead & hest cycle test it like I said above to be sure. Always good to eliminate suspects. Yes, in theory, the problem would go away (or mostly go away) once vacuum is removed from the AAP, but only IF there is a problem with the AAP diaphragm, spring, BVSV, or the vacuum lines going to either device, & IF there are no other problems in the engine system.

Rotor, wires, plugs. Good that they are "newish" & good on the gap. Only thing I can think of here is the quality level of the wires; some sets out there aren't worth a darn, even new. Any idea on the brand? What size are they, 8MM? It might be printed on the wire jackets. Good on testing the vac advance.

Ignition Coil, Voltage Regulator. Again, I worry about the quality of the coil. I had a hell of a time with an "economy" coil I put in, didn't even last 8 months before shorting out internally & leaving me stranded every time, bad hot start issue, crank & crank but no spark. Had to wait 15-20 minutes for it to cool down before it would work. Brand, Part # you used? "Can" or "rectangle" style coil? What did it cost? The Chinese ones aren't worth a darn, poor quality, even the Accel ones these days are crap (IMO) & they charge good $ for those. learned my lesson, now I only use Standard Motor Parts coils. They are made in Mexico but the quality is tons better than the Chinese cheapies.

If you have any doubts, you can test your coil if you have a volt/ohm meter, or again, parts places will test em for free.

Good on cleaning the mounting points for the voltage regulator, it helps a lot in how they work. My only concern here would be if that old bad regulator messed with your alternator any.

Good on the fuel pump & filter. The pump spacer is on there right? Bolts tight (should be 10-15 foot pounds)? Not sure about "pretty much halfway" on fuel bowl level; it's either halfway or it isn't. A little below halfway could be a problem. If it's dead on halfway with the truck level you're good. A little above half is ok too; mine runs like this. You can't totally rule out a fuel issue yet, unless you are sure everything on the fuel side is correct. I know it's a pain but you have to go through everything to be sure. For example: I had a clean gas tank, new rubber filler neck, new gas cap, new fuel pump, new filter, freshly rebuilt carb. I was so excited about the new carb that I hooked everything up to the old rubber fuel lines, just to get it running again. It ran fine, for about a week, then wouldn't idle at all. Took me a week to figure out that particles from the old rubber fuel lines were still breaking loose, & had clogged up my new, fresh & clean idle passages inside the carb. Mega bummer. Of course I had the new rubber lines there, ready to be installed, but skipped doing them in my haste. Dumb. Put the new lines on, cleaned out the idle passages 3 times (this was a PAIN), put everything back, everything good & continued to be good.

Which reminds me of something else. Have you tried taking the gas cap off then running it? Sometimes the pressure relief/vent valve in the cap doesn't work, causing the tank to have vacuum in it, making it harder to draw fuel from. Just a thought & probably not your problem, but it occurs to me.

The only BVSV I find for your truck is a 2 port type; haven't found any 3 port. The 2 ports are still available new from Toyota, cheapest source being Ebay.

Real GOOD idea on the throttle cable; silly me didn't even think of it. I'd try lube-ing it up first with one of these:

https://www.motionpro.com/product/08-0182

You can find them at almost any motorcycle or bicycle shop. Or if you wan to replace the cable outright, they are available for $20-$40, depending on where you get them from. Rock Auto has them for $16-$17 + shipping:

https://www.rockauto.com/en/catalog/...tor+cable,5892

Replacement and/or adjustment specs should be in your FSM. Only independent info I could find on throttle cable adjustment is that the cable near the carb should not be tight (like a piano or guitar string), but have about 1mm of play in it, roughly no more than 1/16" side to side movement. There are 2 nuts holding the cable housing to a bracket, you loosen or tighten to adjust the slack.
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Old 12-26-2018, 11:08 PM
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Well, not much time to look into it today but I did have this dreaded thought. What if my catalytic converter is clogged? The symptoms seem to have gotten worse over time which makes me suspect it is or that my new carb's idle passages are already clogged like yours were . Sounds either time consuming or expensive. I read something about unplugging your o2 sensor to see if the symptoms get better because you are giving the exhaust gasses temporary way out. Obviously wouldn't want to run this way for long.

fuel pump spacer is there and sightglass is halfway, I'm definitely going to replace those rubber fuel lines when I return aswell.

As you suspected I bought a cheapo O'Rielly coil when I was trouble shooting my dead voltage regulator. I was just throwing parts at it so I guess I could throw the old one back on when I get home and see if it helps.

Cable lubing device looks very useful, thanks for that tip

Also looks like this is the cheapest bvsv incase anyone else is looking
https://parts.lakelandtoyota.com/p/TOYOTA_1983_PICKUP-STANDARD-2400CC--AUTOMATIC--4-SPEED/VALVE--BIMETAL-VACUUM-SWITCHING--NO1/3937216/2581027010.html

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Old 12-27-2018, 10:03 AM
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Originally Posted by northoak View Post
Well, not much time to look into it today but I did have this dreaded thought. What if my catalytic converter is clogged? The symptoms seem to have gotten worse over time which makes me suspect it is or that my new carb's idle passages are already clogged like yours were . Sounds either time consuming or expensive. I read something about unplugging your o2 sensor to see if the symptoms get better because you are giving the exhaust gasses temporary way out. Obviously wouldn't want to run this way for long.

fuel pump spacer is there and sightglass is halfway, I'm definitely going to replace those rubber fuel lines when I return aswell.

As you suspected I bought a cheapo O'Rielly coil when I was trouble shooting my dead voltage regulator. I was just throwing parts at it so I guess I could throw the old one back on when I get home and see if it helps.

Cable lubing device looks very useful, thanks for that tip

Also looks like this is the cheapest bvsv incase anyone else is looking
https://parts.lakelandtoyota.com/p/TOYOTA_1983_PICKUP-STANDARD-2400CC--AUTOMATIC--4-SPEED/VALVE--BIMETAL-VACUUM-SWITCHING--NO1/3937216/2581027010.html
Reminds me of an old saying: "Don't go looking for trouble. If you do, it's likely to find you."

Off hand I'd say a clogged CAT wouldn't give you the effects you describe, i.e. the popping at the tailpipe. By "unplugging the O2 sensor" I assume you mean removing the O2 sensor from the exhaust pipe, not unplugging the wire to it. Not exactly clear there. True, removing the O2 sensor from the pipe would give the exhaust gas another way out, IF it's ahead of the CAT. Only problem with doing that as a test is that over time O2 sensors tend to "heat weld" or "rust weld" themselves into the bung, so you'd basically have to destroy it to get it out, requiring a new O2 sensor, & maybe even a new intermediate exhaust pipe.

There is an easy check on the CAT you can do. Next time you run the truck, get it up to full temp then give it some moderate revs, like 2000 RPM steady for 30-60 seconds, then have a look at the CAT. If it's glowing red (or even red/orange or orange) it's majorly clogged or restricted.

Good on the fuel pump spacer, fuel halfway in the sight glass & new rubber lines in the future.

Yep, cheap ignition coils just aren't worth the money you throw at them. If you can get access to a volt/ohm meter you could test the coil to see if the resistance readings are in spec or not, or again any parts place should test it for you for free. The stock ignition coil specs for your truck are: Round "Can" Type Coil, Primary Resistance - 0.8 to 1.1 Ohm, Secondary Resistance - 10,700 to 14,500 Ohms; Type III "Square" or "Rectangular" Coil, Primary Resistance - 0.4 to 0.5 Ohm, Secondary Resistance - 8,500 to 11,500 Ohms. These are "cold" test numbers by the way; resistance will increase in a coil with some heat or use. My rule of thumb is that if I test it & it's out of range on either spec, it gets replaced with new.

I checked Oreillys website for coils for your truck; do you have a round coil or the square one? The square one seems to be the "stock" type.

Want/need info on how to test a coil with a meter? Here's a good article: https://www.aa1car.com/library/ignition_coils.htm

If you do have crud in the internal idle passages of the carb it can be cleaned out, just takes a little doing. When I did mine, I removed the idle mixture screw (AFTER verifying how many turns it was out from seated!), fuel bowl drain plug on passenger side, & fuel cut off solenoid. This opens up 3 access points that are part of the idle passages. The idle jet is inline with the hole where the passenger side fuel bowl drain plug goes. If you look in the open hole, you'll see the brass plug with a small hole in the center of it. With the "straw" on a can of carb cleaner, you can shoot cleaner right through the idle jet.

I did the same for idle mixture screw hole & hole where the cutoff solenoid goes. Sprayed in, let soak for 5 minutes, then blew out (gently) with compressed air. Repeated 2X then put everything back on, remembering to reset the idle mixture screw however many turns it was out. Solved the issue I was having at the time. You can also wash out the fuel bowl this way if you pull both drain plugs. All this is just for info & if you've exhausted other possible sources of the problem.
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Old 12-27-2018, 01:00 PM
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Well I just tested my coil which is the square type and I got 1.5 ohms for my primary resistance and 8,500 for my secondary. I drove it about 3 hours ago and its 65 degrees out so I think its had ample time to cool down? Seems like this thing is out of spec. I really hope this is the source of my troubles.

I was able to pull out and unplug my o2 sensor without destorying it and all i got was the same problems but very loud. Put it back in pretty quick.

thanks again for doing the research, I'm going to give it more time to see if its still hot and then go replace the coil, will report back.

Last edited by northoak; 12-27-2018 at 01:09 PM.
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Old 12-27-2018, 01:41 PM
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Just be aware that many "non-fancy" multimeters will show some small resistance with just touching the two leads together.

Since the primary side of the coil should have a very small resistance to begin with, the 1.5 is probably just the combination of the coil resistance and the multimeter lead resistance. This means that the coil may still be within spec.

What resistance does your multimeter read if you just touch the two probes together?

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Old 12-27-2018, 03:17 PM
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Originally Posted by old87yota View Post
Just be aware that many "non-fancy" multimeters will show some small resistance with just touching the two leads together.

Since the primary side of the coil should have a very small resistance to begin with, the 1.5 is probably just the combination of the coil resistance and the multimeter lead resistance. This means that the coil may still be within spec.

What resistance does your multimeter read if you just touch the two probes together?

DAMN! I believe you are correct, I swapped the coil for another one since O'rieilly has a limited lifetime warranty and got the same reading/problem. Also tried pulling the cap to see if it would help to no avail. Back to the drawing board :-(

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Old 12-27-2018, 04:23 PM
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In true can of worms fashion I opened up the emissions control computer to see if there where any broken contacts. It appears multiple resistors have been cut out? Is this normal?

california emissions control mp-60 from an 83 22r

california emissions control mp-60 from an 83 22r
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Old 12-27-2018, 05:51 PM
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Hummm....

That is interesting. I have seen where some holes go unused (fairly common), but I have not seen parts cut out from the factory.

My best guess is that someone was in there before, but I have no guess as to why.

I wish I had a schematic for this board so I could see what each component is supposed to be doing, but I do not have one.

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Old 12-28-2018, 06:56 AM
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Old87Yota is right. On the less expensive ohm meters, you need to touch the probes together first & let the meter settle down, to find out what the resistance of the meter leads is/are. You subtract that from the reading you get on coil Primary Resistance. I have the $6 Harbor Freight Volt/Ohm Meter. The resistance of the leads on mine is never more than 0.3 Ohms, usually 0.2 Ohms. That would still mean that neither of those coils are in spec though. 1.5 Ohms - 0.3 Ohms = 1.2 Ohms. Max Primary Resistance Spec - 0.4 to 0.5 Ohms. That resistance is 140% too high. By my estimes, that's reducing the voltage/amperage to your Primary by 60 to 70%! No wonder it doesn't run right! I think a 3 hour cool down before testing was ok. Do I understand correctly that the new coil you got from O'Reillys measured 1.5 Ohms Primary straight out of the box?

Ideally, the coil & igniter (ignition module) are engineered/designed to work together to give the best spark energy possible. The igniter/module is what triggers the coil to fire. From experience I know that when a coil goes bad (Primary Resistance too high) it can sometimes damage or destroy the igniter/module, or cause the coil to fire weakly or unevenly, so it's important for the resistance to be in spec.

What is the EXACT coil you got from O'Reillys (brand, part #)? It would be interesting to find out from O'Reillys just what they say the spec for that replacement coil is new. Would also be fun to have them pull the two other models they stock & have them measured/tested for comparison. I checked O'Reillys online catalog & they do not state what the Resistance Ohm Ranges are for any of the square-type coils they sell. Damn odd. On the same page they also show some "can-type" Accel coils; the cheap ones have a Primary of 1.4 Ohms, the "performance" ones have a Primary of 0.7! Even more confusing.
It would also be interesting to find a coil that matches the lower number spec, install it & see if the problem disappears or not.

I double checked the specs I gave you in the previous post to be sure I was right; they are correct. The specs I gave you came from the "How to keep your Toyota Pickup Alive" repair manual by Larry Owens, which I have on PDF File on my comp. It mentions both the "can style" & "square style" coils, & the specs are different for each. I also have the coil specs from a Toyota FSM which I posted on Yotatech here: https://www.yotatech.com/forums/f123...1988-a-305176/

As you can see, they only state the lower in numbers "square style" specs for your model year. There is no mention of different specs.

I have a theory, which is this. In the early 80's, federal regs for emissions & fuel economy were getting tighter (I was around then & remember this). To meet the new standards new car manufacturers started changing things. They were phasing out the use of the old "can style" coils in favor of the new "square style" coils, because the square style was more efficient at providing a "hotter" spark, which would more completely burn the air/fuel mix, therefore reducing emissions. It also gave better MPG if every last bit of fuel were getting burned & turned into power. The square coils were also less prone to resistance variations from heat, so therefore more steady. The can style coils were/are usually oil filled with a steel case. The square style coils are epoxy filled, & have a steel frame on them that helps to dissipate heat.

I think what happened was that Toyota started out building the 1983 model year trucks with the can style coils, to use up ignition parts stock on hand, then they switched over to the square style coils. The specs on those can style coils do not match the specs of any other previous year, so they couldn't be used for anything else; they had to use em up or take a several million dollar loss on useless parts they couldn't use or sell. The 2 different coils for the same model year probably led to confusion in the aftermarket as to exactly what the coil spec should be. Maybe aftermarket parts makers are still using the old can style spec when making their square style coils? Given that your brand new coil from O'Reillys measures 1.5 Ohms Primary this would make some sense. Either that or there quality control and/or engineering of their parts is slacking big time.

This theory might also explain the "clipped out" parts on your emissions control board. It also could be that Cali emissions were different from the rest of the country (more strict than FED), so the board has to work a little differently. It might have been as simple as Cali boards not needing certain parts. Manufacturing wise, it's easier & cheaper to make something just one way, with all of the parts, then just "snip away" those that aren't needed. Less expensive than engineering, designing & making 2 separate boards. Electronically it could work. I would love to see the circuit "trace" side of that board to verify.

BTW that control board look very clean & in great shape. No bulged capacitors either. It's probably ok.
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Old 12-28-2018, 08:36 AM
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Originally Posted by 13Swords View Post
Old87Yota is right. On the less expensive ohm meters, you need to touch the probes together first & let the meter settle down, to find out what the resistance of the meter leads is/are. You subtract that from the reading you get on coil Primary Resistance. I have the $6 Harbor Freight Volt/Ohm Meter. The resistance of the leads on mine is never more than 0.3 Ohms, usually 0.2 Ohms. That would still mean that neither of those coils are in spec though. 1.5 Ohms - 0.3 Ohms = 1.2 Ohms. Max Primary Resistance Spec - 0.4 to 0.5 Ohms. That resistance is 140% too high. By my estimes, that's reducing the voltage/amperage to your Primary by 60 to 70%! No wonder it doesn't run right! I think a 3 hour cool down before testing was ok. Do I understand correctly that the new coil you got from O'Reillys measured 1.5 Ohms Primary straight out of the box?

Ideally, the coil & igniter (ignition module) are engineered/designed to work together to give the best spark energy possible. The igniter/module is what triggers the coil to fire. From experience I know that when a coil goes bad (Primary Resistance too high) it can sometimes damage or destroy the igniter/module, or cause the coil to fire weakly or unevenly, so it's important for the resistance to be in spec.

What is the EXACT coil you got from O'Reillys (brand, part #)? It would be interesting to find out from O'Reillys just what they say the spec for that replacement coil is new. Would also be fun to have them pull the two other models they stock & have them measured/tested for comparison. I checked O'Reillys online catalog & they do not state what the Resistance Ohm Ranges are for any of the square-type coils they sell. Damn odd. On the same page they also show some "can-type" Accel coils; the cheap ones have a Primary of 1.4 Ohms, the "performance" ones have a Primary of 0.7! Even more confusing.
It would also be interesting to find a coil that matches the lower number spec, install it & see if the problem disappears or not.

I double checked the specs I gave you in the previous post to be sure I was right; they are correct. The specs I gave you came from the "How to keep your Toyota Pickup Alive" repair manual by Larry Owens, which I have on PDF File on my comp. It mentions both the "can style" & "square style" coils, & the specs are different for each. I also have the coil specs from a Toyota FSM which I posted on Yotatech here: https://www.yotatech.com/forums/f123...1988-a-305176/

As you can see, they only state the lower in numbers "square style" specs for your model year. There is no mention of different specs.

I have a theory, which is this. In the early 80's, federal regs for emissions & fuel economy were getting tighter (I was around then & remember this). To meet the new standards new car manufacturers started changing things. They were phasing out the use of the old "can style" coils in favor of the new "square style" coils, because the square style was more efficient at providing a "hotter" spark, which would more completely burn the air/fuel mix, therefore reducing emissions. It also gave better MPG if every last bit of fuel were getting burned & turned into power. The square coils were also less prone to resistance variations from heat, so therefore more steady. The can style coils were/are usually oil filled with a steel case. The square style coils are epoxy filled, & have a steel frame on them that helps to dissipate heat.

I think what happened was that Toyota started out building the 1983 model year trucks with the can style coils, to use up ignition parts stock on hand, then they switched over to the square style coils. The specs on those can style coils do not match the specs of any other previous year, so they couldn't be used for anything else; they had to use em up or take a several million dollar loss on useless parts they couldn't use or sell. The 2 different coils for the same model year probably led to confusion in the aftermarket as to exactly what the coil spec should be. Maybe aftermarket parts makers are still using the old can style spec when making their square style coils? Given that your brand new coil from O'Reillys measures 1.5 Ohms Primary this would make some sense. Either that or there quality control and/or engineering of their parts is slacking big time.

This theory might also explain the "clipped out" parts on your emissions control board. It also could be that Cali emissions were different from the rest of the country (more strict than FED), so the board has to work a little differently. It might have been as simple as Cali boards not needing certain parts. Manufacturing wise, it's easier & cheaper to make something just one way, with all of the parts, then just "snip away" those that aren't needed. Less expensive than engineering, designing & making 2 separate boards. Electronically it could work. I would love to see the circuit "trace" side of that board to verify.

BTW that control board look very clean & in great shape. No bulged capacitors either. It's probably ok.
Forgive me for I think my brothers cheap o multimeter led us astray. It reads .8 when I touch its two leads together


And the coil reads 1.3 this morning after cooling all night so I guess it is in spec at .5


The coil is the import direct 23-0260 : https://www.oreillyauto.com/detail/b/import-direct-ignition-4489/ignition---tune-up-16776/ignition-coils-19690/ignition-coil-12493/90c5da72ae86/import-direct-ignition-coil/230260/5732205/1983/toyota/pickup?q=Ignition+Coil&pos=0

Still trying to chase down this hesitation/misfire and at times stalling when first accelerating though. I'm about to drive about 7 hours up highway 5, wish me luck and send any ideas my way! :-(




Last edited by northoak; 12-28-2018 at 09:57 AM.
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Old 12-28-2018, 04:46 PM
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No reason to have to forgive you. We all have to learn this stuff the 1st time. The important thing is you got the meter thing figured out. Your math looks right so the coil is good at that reading. That is the coil I figured you had. Some quick research indicates that brand is made by Standard Motor Parts, usually a very reliable, quality brand. Just curious but are there any markings on the coil or it's box, as to where it was made? Some info I have leads me to believe that it might have been made in Japan, in which case the quality is very good. Just want some verification for future reference.

Well, if the coil is OK, that leaves the igniter/module (rare that these would do that) or a fuel issue, likely the in carb. I still think it could be the idle circuit passages being clogged, maybe even a partial obstruction of the idle jet itself. When this happens, the engine has to get most or all of it's fuel from the main jet side. Under normal operation, it draws from both the idle & main jets, even above engine idle speeds. That means the engine could be running kinda lean. Be careful not to push her too hard because an engine that goes too lean can grenade. Hopefully the idle passage is only partially blocked & it's not too lean. I'd suspect this is the case from your descriptions of what it is doing.

It's also possible your fuel cutoff solenoid isn't working, isn't hooked up or isn't getting power. It's wired up to your engine "run" circuit & when energized (key in run or start positions) it retracts a small shaft with a rubber tip on it, opening up the idle passage in the carb. When you turn the key is off, the shaft clicks forward & blocks off the idle passage, preventing any more fuel from flowing in the idle circuit. The fuel cutoff solenoid is there to prevent the engine "dieseling" or running on after you shut it off, & to keep gas from dribbling out the idle port into the intake when the engine is off.

You said you got the TOY-505 carb from National. I looked the carb up & from pics of it on the web, it looks like you have 1 green connector on it, that has connections for both the electric choke & the fuel cutoff solenoid. Did you hook up this connector when you got the carb changed out? If you did hook it up make sure the connectors are fully seated. There is a latching mechanism on it that lets you see if it's fully seated or not. If fully connected & the problem is still there, it could be that the terminals in the connector on the wire harness side are dirty & preventing good contact. It could be that simple. Clean em out with some electrical contact cleaner or even WD-40 & then shoot some compressed air at them.

More rare: check for any damage to the lugs or receptacles in the connectors. Rarely 1 of the old spade lugs breaks out of the connector & gets left behind. Also check for any damage to the wires from the harness side & the carb side. I know the carb is new & the wires should be too, but ya never know.

Have a safe trip boss & take her easy.
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