chip84

It's official, I am a toyota newby and this is my very first post. I have a 1983 4x4 pickup with the 22r and I cannot get it to idle right. I just rebuilt the carb, it was absolutely filthy, but when I put her all back together, it didnt idle any better. I have replaced a few of the vacuum hoses, but honestly most of them aren't cracked bad enough to need replaced anyway in my opinion. As long as I keep the motor at 2000 rpms, it will run. But let it drop below that, and it will try to die. Sometimes it will almost die, then it will come back to life for a few seconds and try to die again. When I first start it, the truck will run at high idle alright, but as soon as you kick it down to regular idle, it will die unless as mentioned before you keep it at or above 2000 rpm. I have the lean/rich mixture screw turned out 2.5 turns from seated. I also have what I beleive is the warm idle screw backed out 2.5 turns as well. The AC idle speed screw, which I have no idea what is does, is screwed in as far as the spring will let it go. And apparently there is a cold idle screw that is really hard to see, and I have not messed with it. I have checked the fuel cutout solenoid and it does click when the key is turned on, which I understand is supposed to be correct. I am looking for any ideas on how to help this old thing out because it is really hard to run three pedals with two feet, to maintain 2000 rpm's at all times!! Also the guy I bought this truck from said he thought is had two week cylinders, could that affect how the truck idle's??? I havent actually tested the cylinders yet. Thanks!!

yota8083

if two cylinders have low compression then that is why it is not idleing. You have bigger issues than the carb if thats the case.

chip84

I see. I have another motor, I guess I will have to swap them. I mean, I have drove this truck down the road probably 30 miles, it just seemed underpowered. I figured if it ran good enought to drive down the road, that it would idle too.

Green_slime

could be a number of things timing, distributor, plugs, wires, cap, rotor, check all those first before you go swapping motors for no reason

chip84

So how likely is it that the low compression is causing this truck not to idle? I had an old boat motor once and it had low compression in one cylinder (of two) and it ran fine, it just didnt have the power it should have. But as far as idle it ran fine. So far I have rebuilt the carb, replaced the fuel filter, plugs and wires, replaced some of the vacuum lines.
I did get to spray some carb cleaner in the carb as the motor was dying and it did make it run for a few seconds, then it would try to die, then I would spray and it would run for a couple seconds, etc.
I have done some research and am wondering if it would be a good idea to try replacing the BVSV that controls the auxiliary accelerator pump. Although I have read that the AAP has no effect when the motor is warm, I understand that it just gives the motor a little extra fuel when it is cold. The only reason I would not try this is that I drove the truck for 20 miles, it was good and warm, and anytime I pulled up to a stoplight or turned into the drive way it still tried to die, this makes me think that the BVSV for the AAP is fine.
Any advice is much appreciated.

shmitty

I have the same problem and i decided to go with a weber setup its on its way right now, but i have spoken to several guys that strictly fool with toyota pickups and they have had several cases when you rebuild the factory carb it still doesnt act right. I dont know much on carbs but my 81 at the moment has real bad carb issues.

shlobeck

This is absolutely true...I had an '82 which I spent $700 on a "rebuilt" carb...it still ran like #@$^%!! Now I have a restored '83 with a weber and it runs flawlessly...My '82 never ran this good...if you're going to spend the money go with a new carb...

maistroyoda

^^^X2 I did the exact thing. I wanted to save $$ by rebuilding so I spent like $50 for a Napa premium rebuild kit. It still wasn't the same so I ended up buying a Weber 32/36. Now the truck runs great except for the first cold start. I have to crank the engine over like 5 times then high idle it for a minute or two.

chip84

To date I have done the following and still cannot get my truck to idle: rebuilt carb, new fuel filter, replaced some of the vacuum lines (although none look terrible), new plugs, new wires, new cap and rotor. I also checked the compression and got 120, 120, 130,120. I have no clue how these numbers compare to how they should be, but thats what they are. When I bought the truck I was told it had two weak cylinders, however I dont see that based on those numbers; if anything they are all weak. The symptoms are still the same: it will run at high idle when you first start it around 2000 rpm's. But as soon as you knock it down to regular idle it will not run unless you keep your foot on the pedal and maintain 2000 rpm's. Sometimes it will go from 2000 almost down to nothing and then it will revive itself back to 2000 and do that process a few times and die, or it may do that for a few minutes and then die. Ultimately it will eventually die, it WILL NOT idle on its own unless the high idle is activated. Any advise is truly appreciated, the quicker I can figure this out the more hair I will have left on top of my head!! I really hate to spend money on a weber conversion unless that would guarantee to fix my problem, please let me know what you think, thanks.

peapicker

Had an 87, would'nt idle smooth or run like it should. After a tune up, compression check, and countless other checks and re-checks, rebuilt the carb. It ran worse! Took the factory carb off dropped it into the ol file 13! Installed a weber and holy crap it ran great! Go Weber!

Gov't Mule

Weber 32/36 FTW!! Like maistroyoda said, it's a little temperamental on a cold start but damn they run nice on a 22R!

toyomoto

make sure you check your timing, if you dont have a timing light, you can loosten the locking bolts to your distributor and twist the distributor slowly in either direction while the engine is at a low idle. thats a cheater way to do it but it can sometimes work. for the air fuel mix screw, make sure you are adjusting the right one, toyota carburators came from the factory with a "non serviceable" air/fuel mix screw. and to actually get to it, you need to drill out a section on your carb! also check your choke on the carb and make sure it is not stuck. this wouldn't cause as severe an issue like your having, but it won't hurt to check! this site explains good backyard techniques and what not.http://www.bluebassdesign.com/boonin/carb_faq/ Thats my 0.02$ dont know if it helps but there ya are!

chip84

I have the air/fuel mixture screw set at 2.5 turns out from being seated. I have messed with moving the distributor, and seem to have it in the best position for now, I dont think that is the root problem. I started the truck today and it is cold here in iowa, so the truck immediately went to high idle, and ran for like 5 minutes in the driveway. Then I got in and tapped the gas pedal and immediately the truck dies.

chip84

so...........are these numbers acceptable for compression? 120,120,130,120? Can the compression affect the idle?

83

Pretty simple google search (or get a manual-if you're trouble shooting your truck how can you do it without a manual?) found this.

Compression pressure:
1,177 kPa (12.0 kgf/cm2, 171 psi)
Minimum pressure:
981 kPa (10.0 kgf/cm2, 142 psi)
Difference between each cylinder:
98 kPa (1.0 kgf/cm2, 14 psi) or less

I'm guessing these are the "normal" specs from the manual, but I don't have mine in front of me right now. So anything under 142 is low compression, but while I was searching for you, I also saw many posts that mentioned compression numbers like yours where the truck ran just fine.

Those are pretty low numbers, though...

Pumpkinyota

An internal combustion engine will run on 90 psi minimum. 120 is not all that god-awful. The three basics (which you seem to already know) are fuel, spark, and compression. The compression is probably not a factor in your idle issue.

Your two main areas of concern, then, are fuel and spark. Spark is the easiest to diagnose, and I would start there. First, disconnect the coil plug from the distributor, lay the metal contact close (1mm or so) to a bare grounding surface ( I always use the exhaust heat shield), and crank the motor. You should see a nice big spark. If so, pull a spark plug, and lay the contact on the heat shield, replace the coil wire on the distributor, and crank the truck again. If you get weak spark for either test, it could be time for a new ignition component of some sort. Plugs, wires, cap and rotor can be had for under 50 bones. If you have an RMS meter, or someway to measure resistance, maybe try measuring your plug wires, they should be less than 6 K-ohms. Plugs should be replaced with a factory style plug, like an NGK or a Denso.

If ignition timing and power seem to be ok, than air/fuel may be where you investigate. Carbeuration on these trucks can be a nightmare unless you like plumbing vacuum, here are the two best information sources I have found:

http://www.bluebassdesign.com/boonin/carb_faq/#aap
http://www.pirate4x4.com/forum/showthread.php?t=249626

Both of these show you how to remove as much vacuum from the works as possible, and still have a working carb. This may be a good starting point for carb and air/fuel tuning.

Good luck, I hope this was helpful!

cdg

Well I have a few suggestions. First I second the notion that you should start with spark - it's simpler to diagnose. Make certain you're getting a nice fat spark. Your plug gap should be in the ballpark of .032". That's off the top of my head. They can be up or down about .004" before it really matters a lot. Make sure your ignition wires are on in the correct order - 1342 is the firing order. Putting them in the wrong order can cause your symptoms.

Next question - do the power brakes seem to work? If not, you could have a ruptured brake booster diaphragm which in some cases will make the truck run like crap - especially when your foot is on the brake! The test is simple - disconnect the brake booster and plug off the fitting on the intake manifold. If the truck runs better than viola!

Second, I disagree with how you set your idle mixture. Usually these trucks never ever need adjusting. Once disturbed the best way to "guess" idle mixture is to unscrew the idle mixture until the truck starts running OK. Then screw it in until it starts running like crap. Turn it out between 1/2 and one full turn and that's your idle mixture setting. It isn't perfect but it can get you in the ballpark quickly and effectively.

Next on how to check for vacuum leaks. Spray carb cleaner around the various vacuum hoses and fittings. The truck will run poorly when you spray in an area where there is a leak. Leaks around the intake manifold gaskets and carb base gaskets can casuse the behavior you are describing. Sometimes there are very small cracks that can make the difference between running and not and you may not be able to see them - especially in that tangled rats nest of hoses brought on by the EPA.

The AAP diaphragm - ah what a wonderful contraption. I would replace it no matter what - it's 10 bucks so bite the bullet and guess on that one. They fail on these trucks once ever 20 to 30 years so the worst case is you preemptively fixed something that was probably going to crap out anyway.

The BVSV I think is the unit that controls the AAP - it can fail with old age. Don't trust that just because the truck is warmed up that the vacuum switches work... Some models work fine with the AAP plugged off.

Try to look for a black sooty texture to your exhaust - if you see it than you are running rich. You may also be running out of gas - try to figure out which it is.

Take a peek in the sight glass for the float level - is it high in the sight, in the middle, or very low? This could offer you a clue...


I had a problem once with my 1980 that was similar. It didn't do it all the time though. Upon rebuilding the carb I found the leahter seal on the accelerator pump to be compromised. I did rebuild the entire carb but it was that leather accelerator plunger that I think was all it needed. You could try reviving your existing plunger with a little motor oil massaged into the leather seal.

The true test of an idle cut solenoid is whether or not it functions - not if it simply "clicks". It could still be jammed up. Guessing on a new solenoid is expensive so my suggestion is if you believe it may be the problem to find a very shallow bolt with the same thread pitch and gently tighten it in its place. Be careful not to torque it - better to have a very small leak than to ruin your carburetor. The engine will still stop when you turn it off without the solenoid - the point of it is to cut the idle circuit to prevent "dieseling" on a hot engine - when compression combined with a hot exhaust valve will keep teh engine running even after the ignition source is taken away (the coils are grounded).

Your truck likely has an EGR system. The best test for it is to simply block it off. The best way is to get some steel plate, cut it with some snips to the shape of the valve flange and drill the proper holes (they can be oversized for ease of fabrication/fitting). Then simply lay down the gasket, then your plate, then bolt the EGR valve back down over top of things. Then plug off all associated vacuum lines to the EGR system. If the truck runs better than you can decide if you need to reinstall the EGR system or not based on where you live and how much you care for the environment.

You might also try plugging the vacuum line from the carbon canister. I doubt that will fix your woes but it may help...

Lastly - double check your fuel filter. Installing a new one can never hurt but once installed make sure the arrow points to the fuel output. If I'm not mistaken one of the fittings on the fuel filter goes to the feed from the tank. The other (the one with the arrow pointing out) goes to the fuel pump inlet.

Pick through that list and maybe it will help. The compression you listed seems low but enough to get it to run good to me. Desmogging your truck entirely may be the best route for you. The rule of thumb to me is to desmog only if your truck is running badly. Seems like it may be the best thing in this case - eliminate all sources of failure.


Sometimes depending on how many (and how severe) miles are on the truck the carburetor can simply be worn out beyond rebuild - the throttle shaft could be leaking badly. The stock design was an excellent design considering that the early to late 80s were the Dark Ages of the automobile world. The Weber harkens to a simpler time before all the complications of Federal regulation. Tons of old Yotas are still out there with stock carbs but bear in mind that it might be time to just let this one go.

Pumpkinyota

Damn, I forgot about the brake booster, good call.

.032 is the correct spark plug gap, per the Toyota FSM.


If you do decide to diagnose vacuum/smog, and you haven't had experience testing for vacuum with propane, carb cleaner, or a stethoscope, here's an alternative method:

1) Follow the directions linked in my above post to de-smog completely
2) Check idle on your truck, see if the problem has cleared.
3) Re-introduce the smog components one component at a time, in order of operation. Run the vehicle between every new piece you re-install, and look for the idle problem to manifest. When it does, you have begun to isolate the issue, replace problem components.

Also, replace your AAP and BVSV no matter what. CDG is right, they are inexpensive and easy to replace, and both are prone to failure. Worst case, you have done some preventative maintenance that could save your butt later.

theboomboom

Long time lurker chiming in, hopefully this helps if you still haven't gotten your truck running-

I recently experienced pretty much this exact same issue, and I went through a similar process in diagnosing it. What it came down to was two things- the connector for the idle solenoid had a wire pulled out of it and the fuse labeled engine in the fuse block was blown. I pulled an identical connector out of a tercel, swapped the wires around, installed it then replaced the fuse and it fired right up. After a little more tuning, it purs at 700 rpm beautifully. Hope this helps.

1990yota-pickup

take some pictures.. maybe we can see somthing that you dont see...