NathanVos

New to the forum. I can add this question in the newbie frequently asked questions if need be. I searched for possible answers in the threads, but I only could find information on similar issues with EFI engines. Perhaps I was using the wrong search terms.

I bought a 1982 2WD 1/2 ton with the 22R engine, California model with 122,000 miles on it. Automatic transmission with overdrive. I bought the truck on the cheap and figured it might be an easy fix or not too much money lost if I couldn't fix it. The previous owner said that about a month ago the engine would begin to idle rough in gear and eventually buck and die. It idles fine with a small shake in park or neutral, and drives great upon acceleration and at highway speeds. It also does not have this issue when cold. It will idle in gear and not give me death rattles when cold.

As a band-aid to get it home (I didn't want to have to slip it in neutral every time I was at a stop light), I had to raise the warm idle up to 1300. When put in gear it will sit at about 900 and shake but not die. Anything less than that and it will buck and die. Before I changed the secondary diaphragm (I don't know what it is called), when i bucked and sputtered, it would belch out black smoke. Since I've changed that, it does not emit black smoke but it will still shake, buck, and die.

I have to admit. I am used to working on vehicles with far less vacuum hoses and random emissions systems. I have been intimidated looking at all those God forsaken vacuum hoses. I might go buy a bunch of vacuum caps and start pulling hoses just to relieve some anxiety the next time I look at it.

Anyway, all seems to be stock on the engine. Aisan carburetor. Even the idle mixture screw has the original cap. (Could the mixture screw have come loose?) All the hoses seems to be in place as per my old Haynes manual for that year and California model. The smog pump has been removed a while back.

I pulled the vacuum line on the secondary diaphragm (I don't know what it is called, I believe it is for cold start drive-ability) and it was full of gas. So, I got a carb kit and replaced that diaphragm and I replaced the accelerator pump diaphragm while I was there. That secondary diaphragm did have a puncture mark in it, but of course with my luck, this was not causing the issue. Also, I changed the oil. Previous owner said he changed it about 800 miles ago, and well, the crankcase had gas in it. Like way too much gas. That oil was very thin. I put a new filter on it and put in fresh oil. After having changed that diaphragm though, the oil does not seem to be contaminated with gas. I have driven it about 300 miles and the oil seems fine. The exhaust does not have blue smoke coming from it and the tailpipe does not suck in a sheet of paper, so I do think this is a gas related problem.

There were some vacuum lines disconnected, I plugged them back in as per the manual, but that did not make a difference as to the idling in gear.

Now, I've blocked the EGR vacuum lines, didn't make a difference. I checked the timing - the hood said 8 BTDC and that was where it was at. I advanced and retarded the timing and tested it out but with the idle at about 900-1000 the darn thing still shakes and sputters in gear when warm and then dies. When I get the RPMs higher, it does not die.

I ran a propane torch over the area - and nothing changed.
I can run it at high idle to get by, but with the idle so high, it diesels after being turned off. I have to shut it off in gear so as not to allow the run on.

Does anyone have any suggestions? Nice truck, just this one problem has me stumped. It seems to get good gas mileage if driven down the highway.

NathanVos

I drilled out the cap on the carburetor. I then turned the mixture screw all the way in and the idle is much smoother. It does not shake as much at 800 rpm. However, when put in gear it will sputter and then die. It does not seem to be as bad but it still dies when the idle is not around 1300 or higher. Is there anything else that controls the idle circuit on this year motor? Choke is fully operational so it is not that.

millball

Sounds like the carbs low speed circuit is inop. Symptoms are classic.

Runs better when cold because choke is temporarily enriching mixture.

Runs fine at speed because the low speed circuit is not used then.

Carbs are a pain, even more so when using modern oxygenated fuels. Even perfectly good carbs can be rendered into junk by laying a few months with alky fuel in them.

If you get it fixed, keep driving it. Lack of use is worse than abuse.

I'll never own another carbed machine except for vintage motorcycles and maybe a model t ford.

NathanVos

You think a full rebuild/cleaning would do the trick? Or is there something else that may be causing the issue at idle?

millball

Of course you need to verify the basics first. EGR closing tightly at idle(plugging EGR vacuum lines wont'do it), correct ignition timing and timing advance, no vacuum leaks, then it's likely a carb issue.

I would say that engines with tight valves don't like to idle. Chech the valve lash.

I said these same words to another guy, the other day::

All you can do is try. Every carb is a unique entity unto itself and no one knows what hands have molested it in the last 35 years.

Good luck.

NathanVos

Thanks for the help. I think Ill rip out the EGR tomorrow and block it off just to be sure. If that doesn't do it, Ill have a good old fashioned cussing episode and then take apart the carburetor.

Thommo Thompson

dirt always finds its way into the slow jet. this is where ur problem will most likely be. u mentioned u turned the mixture screw in all the way and this increased the idle speed. this suggests the base idle is set to run too high and is idling off the main jet instead of the idle circuit. the idle jet is probably completely blocked reaulting in the idle circuit acting as a vacuum leak through the idle air bleed.
when cold, the choke adds so much suction it pulls the fuel through the slow jet, but if its blocked and previous owner tried to rectify the issue by raising idle speed, then the choke will now cause it to suck fuel through the main jet.
bottom line, is this carby needa to be cleaned out.

Melrose 4r

Carbs aren't really voodoo. Take this carb apart and understand how it works. If the crankcase had fuel in it,
you either have a bad diaphragm on the fuel pump or the float in the carb was stuck/porous/overflowing.
a carb rebuild should help.

NathanVos

Well, have the carburetor cleaned up and rebuilt with the kit I got. I will let you guys know how it goes when I install it tomorrow. It was pretty dirty on the inside, and it seemed like it never had been cleaned, at least not for a while. It wasn't as bad as I thought it was going to be. I had rebuilt a couple motorcraft 2150's, a 4bbl autolite on a lincoln, and a 4 barrel holley before, but was wary of this one. I guess my fears were unfounded - at least I think, I'll have to see if it starts tomorrow!

NathanVos

Got the carburetor on and now it does not sputter and die in idle in gear. I need to tune it as it is still shaky, but this is an improvement, the not dying and all. I think that did the trick. Thank you all for the advice.

On a less enthusiastic note, it was the fuel pump that was dumping gas into the crankcase. Best part of the story, the previous owner had sheered one of the fuel pump bolts off at the head then RTV sealed all the way around it to keep it from leaking. I think that is how the diaphragm was ruptured as that stuff was all over inside that pump. It looks like he tired to hit the broken bolt (it is less than flush with the head where the head came off the stud) off center with a punch to get it to go around but with no luck; he just mangled it and the outer threads in the process. I was not able to get a punch centered to be able to get a drill bit on it. I have tried for the past two hours to drill it out with a regular small bit for an easy out then with a left handed drill bit with no success.

I'm trying to decide what to do. I can't get a welder over there to weld a nut to the stud - don't know if I would want to anyway on a head. Should I pull the head and get it tapped and died or block it off and install an electric fuel pump? Or is there another miraculous way to get this stud out of the head?

I'm sitting here with both an electric 3-4 psi pump and a mechanical fuel pump. I really don't like my options here.

Thommo Thompson

i love electric pumps. be gone with u mechanical beast pump!! be sure to mount it at the rear of the car or u will have vapour locking issues.

thank me later when u never have to worry about fuel pump problems.
word of warning.
be aure to run the pump from a brand new circuit getting power directly from the battery and through a good quality fuel pump relay.
id even go as far as to have a voltimeter wired in to the fuel pump power supply so u can monitor the quality of voltage going to the pump. poor electrical connections destroy electric pumps. make sure you run the earth wire from the pump to a nice clean corrosion free environment inside the cabin. corrosion on either + or - on a fuel pump wiring is recipe for premature death.
when wired up well and installed at the rear, an electric pump is the best solution.

NathanVos

Yeah I tried to drill that bolt out again, and it was awful. I think I'll take the advice and go with an electric fuel pump. What do you recommend for an electric fuel pump? I have this one from O'reilly's. Precision Fuel Pump E16041. It was 50 bucks. I'm sure I could do better for about the same price. Also, it doesn't have a return fitting. Is that something I can get with another electric fuel pump? The mechanical fuel pump had a line to the carb, a return to the tank, and one from the tank. This fuel pump only has one line from the tank to the carb. Thanks in advance. Everyone has been a big help.

Thommo Thompson

just as long as it is listed as a carburettor pump. most of the ones that are generic like this are low pressure for carbs.
i cannot see ur particular model online so cannot confirm. but i use this.
https://m.ebay.com/itm/New-Electric-...-/272357036741

Old83@pincher

O/K...but you still have to get the broken bolt out of the head to properly put on a block off plate!

So if it isn't too mangled use a small centre drill, say a #2 (used for putting centres in shafts to turn in a lathe) and start the hole with that, then drill it out to about 17/64" (.265"...I believe the bolts are M8 x 1.25 so the tap drill would be 6.75mm or .270"...FYI...the tap drill for a metric thread is subtract the pitch from the diameter...ie...M6 x 1 tap drill is 5mm). Get a good quality easy out and with a hot engine it should come out. Its amazing how much easier these things come out with a hot engine, don't try it on parts that could warp or twist. You may have to gently tap the broken bolt with a hammer and drift or even more gently the end of the easy out. Don't break the easy out or you'll be in a world of s##t! If all else fails just keep slowly and carefully drilling it out. You may be able to re-tap the hole or just heli-coil it. Use good sharp drills such as those TIN coated ones (the yellow ones!) and a good drill and tap oil such as 'Cool Tool'. Don't use engine oil as it contains no sulfurized compounds that make drilling and tapping easier. You could use EP gear oil but at this point I wouldn't screw around with being cheap on a can of cutting oil. It is imperative, and I cant stress that more, that you are drilling to the absolute best to your ability in the centre of the broken bolt.

I cant even imagine the incompetence of the previous, mouth breathing, knuckle dragging troglodyte owner breaking off those bolts in the first place!

I've never had issues with mechanical fuel pumps and prefer them to electric...just some thing about electric motors next to gasoline that kind of un-nerves me! Yup those new cars all have electric pumps in the gas tank!

I just re-read your posts and if you have or want to get some transfer punches they may help you get a good centre on that bolt. Sounds like a heli-coil is going to be the ultimate end.

Thommo Thompson

haha id just be blocking it with a plate well siliconed and the one bolt hole thats left hahaah.

Old83@pincher

Well...yah.

A slap-dash repair always seems to fail at the worst of times.

But Its not my engine that's going to puke oil all over the place and possibly run out of oil.

To quote an old guy I worked with during apprenticing," one bolt is no bolt!"

Thommo Thompson

how about a metal tek screw then haha

NathanVos

Sorry for the late reply, I quit getting notifications on the thread so I forgot to check back. As for the fuel pump debacle, I just went ahead and got an electronic fuel pump for cheap off ebay, I believe the one Thommo Thompson recommended. I put it as close to the fuel tank as I possibly could and wired in a relay as per Mr. Thompson's suggestion. All ground wires were attached to an existing place where other negative wires had been installed. As for that stupid, worthless, no-good-for-nothing fuel pump bolt, I cut out a thin plate of steel to form a cover, high temp RTV sealed it, and put a couple giant fender washers (they mostly covered the fuel pump lever hole) and held it on with the last remaining bolt. I really tried to get that bolt out. I used a cheap punch at first (I assume it was cheap), and the punch broke striking the broken bolt. I even bought a cobalt drill bit and it wouldn't cut into it. I don't know what bolt the previous owner put in there, but I do not believe it was the factory bolt. After spending some very frustrating time with it, I knew I would have to take the head off just to get that bolt out so I believe getting an electric fuel pump and blocking it off was the only feasible solution.

As for how it runs - it runs great now! After the carb rebuild and float adjustment, I used a vacuum gauge to tune the idle mixture and ignition timing. It runs steady at factory RPM at 19 inches of HG. No needle wander on the gauge. I really like this truck. Been easy enough to work on. Never owned a foreign vehicle before (unless you count a 1976 CB750 Super Sport)! Got a pretty good deal on a small truck with 122,000 miles for $500! Now I am the proud owner of a well running Toyota 22R. Thank you everyone for the help. This forum is very interesting, and I will continue to enjoy reading the threads and info on this site.

Here's a pic of the vacuum gauge reading:

rickc5

If you don't mind my asking: I'm facing a carb rebuild too, and I also am intimidated by this oddball Aisin carb. When you bought your rebuild kit, did it come with a detailed set of directions? If not, where did you get the necessary info on rebuilding the carb? My option is a weber carb, but that's a pretty expensive option. BTW- I have the factory shop manual.

NathanVos

I bought a Walker rebuild kit. Mine only came with an exploded view of the carb, which I did find helpful at times. Really, I just looked at the carb and dove in using common sense and not forcing something if it wasn't going unless I was sure it was supposed to come out (I marred the old needle seat pretty badly but I knew I had a replacement in the kit - I had to use WD-40 and an electric impact to get the old one out). It had a few small leftover parts after install, but that is because they changed some parts on the carb over the years not because I didn't install everything. When taking it apart, I took a lot of pictures with my smartphone, and placed the parts on an old white rug starting at the top left and moved to the right as I disassembled it. I also made sure to have the thing disassembled and reassembled all in one day so as not to forget where it all went. I also refrained from drinking beer to keep my mind clear!

I did this a few weeks ago, so bear with me. It comes apart in three horizontal layered main pieces (like thick plates). If you start at the top, I think there are 5 screws holding it together that run through all three plates. I think I may have removed the diaphragms before this. I kept the choke horn on as one screw holding it on stripped (those two screws are on the back top of the carb). After getting those three parts taken apart (and the float and needle taken out - make sure the float is still operational) and getting the jets out and the slow jet (You'll see it in the exploded diagram), I soaked it in a gallon of lacquer thinner - only 12 bucks. After an hour or so, I put on some goggles and carb cleaner with the straw and blew out every hole on the things and scrubbed with a tooth brush.

As for the float adjustment, if it was good before the carb was removed, i wouldn't touch it too much to change the float setting when assembling. I had to tinker with mine because I installed a different fuel pump. I got it on the fourth try right in the middle of the sight glass.

Oh and be careful when assembling so as to have the choke and throttle mechanisms correctly in place. I had mine assembled before I realized that none of it was hooked up and I could connect any of it with it assembled so I had to take it apart, attach the choke mechanisms, and reassemble.

Oh, I had to drill out the choke rivets to get the new diaphragm and gasket in and I had to drill out the mixture screw cap as well to clean and adjust the mixture needle. That stuff really grinds my gears by the way - these "tamper proof" '80's carbs. More like "pain-in-the-a$$" Wouldn't see that on my 71 Mark III ! Anyway, I think that is the main stuff. There might be youtube video out there, but I didn't use one. It wasn't all that hard, but I did not find it as simple as a Motorcraft 2150 either.