Need help from Carb gurus with 22r

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jmoore
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My tercel:: 1985 Tercel 4WD SR5 1983 Tercel 4wd SR5

Need help from Carb gurus with 22r

Post by jmoore »

Hey guys, I know it’s not a Tercel, but I need some help from a group of helpful and knowledgeable guys. My 22r 4x4 developed a problem the other day. I was doing some light wheel in’ stalled it once and it rolled backwards in 1st gear, thought timing chain skipped a tooth, checked timing and cam gears, they seem to be fine.
Bogs down really bad with more that 1/2 throttle above 2500 RPM. It seems to be running real rich.
Current diagnostics: with air cleaner cover off it idles fine, unless I turn the linkage quickly it bogs down and fuel seems to burst out of the primary barrel vertically, while the secondary air valve closes and bounces slightly open violently. It will do this indefinitely if I allow it. I have adjusted timing, valve lash, and float settings on the carb. (Stock aisin 35430 double barrel carb).
Engine condition: 220k miles, slight vac leak from brake booster, pretty bad oil leak from oil pan, new air/fuel filter, new plugs/wires/dizzy, vac advance is working as it should. I rebuilt the carb on a picnic table the other day and have the same symptoms before as after(currently on a road trip about 1,100 miles from my garage) All vac lines are routed correctly. Fuel pumpwas new when I bought it last year. Cat isn’t clogged, O2 sensor seems clean...I’m going to replace vac lines today since there are drastically less than a Tercel. It was running fine at 10,000 feet elevation so I don’t think the mixture is messed up, but maybe it took a. Week to adjust and throw it off?
If there’s anything I’m missing I would be stoked to hear from you guys, it’s gonna be a long drive home at 40-50MPH on the interstates(SE Utah to California Coast). Thanks a lot for any input.
Jarf
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Re: Need help from Carb gurus with 22r

Post by Jarf »

Sounds like an issue in the high speed circuit.
How many solenoids are on that carb?
If it has 3, one of them may affect the HS circuit.

The only thing I can think of, would be to make it sneeze a few times:
- Cross #2 & #3 wires, fire it up, blip the throttle a couple of times and it will back fire.
Essentially, back blowing all the internal passages.

May not help, but its cheap, easy and wont hurt anything.
jmoore
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Re: Need help from Carb gurus with 22r

Post by jmoore »

Tried that out this morning, thanks for the thought! Didn’t seem to help, however I do seem to think it’s not getting enough air through the carb. Started our haul home this morning, I’ll update with any progress once I get home. If anyone else has input I can always stop and tinker while the girlfriend and dog get out to stretch.
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dlb
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Re: Need help from Carb gurus with 22r

Post by dlb »

When you rebuilt the car, did you replace the AAP (if that carb has one)? They are a common cause of running rich on t4's when they are ruptured.
jmoore
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Re: Need help from Carb gurus with 22r

Post by jmoore »

I sure did, the old one looked good, but replaced it in case there was a pinhole I couldn’t see with the sun behind it. From what I understand the AAP only helps on the initial transition to WOT from cruising. This problem is constant and I cannot get RPMs above 2500 with more than 1/2 throttle, but it will idle above 2500 in neutral and slight throttle. Which leads me to think it’s something to do with the secondary air valve?? Please correct me if I am wrong.
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Petros
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Re: Need help from Carb gurus with 22r

Post by Petros »

the carb on that engine is actually similar to the one in the 3ac engine, but larger barrels. I can not think of anything that would cause that on the carb IF it was related to stalling it out backwards.

one thing that comes to mind however, if you spun the engine backwards even a bit, after rolling it backwards in first gear, is that you bent a valve or two and now you are not getting compression on two or more cylinders. have you tried a quick spark plug drop down test? you pull one spark plug wire at a time, while it is running and see if the idle drops the same amount, should be the same for all 4 cylinders. if one or more pulled spark plug wire results in no slow down in idle speed, the problem is in that cyclinder. you can also do a compression test, even a slightly bent valve will reduce compression, but still allow it to run. if that is the case, the head had to come off.

when the engine is spun backwards, slop in the chain could cause enough delay in retracting the valve and allow a piston to strike the valve head. best check it out, or rule it out.
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
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'85 Tercel 4wd DLX auto(daughter's daily driver)
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jmoore
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Re: Need help from Carb gurus with 22r

Post by jmoore »

We made it home after a couple days, tried the drop down test yesterday. It seemed like they all dropped the same amount, but I’m going to check compression after a friend returns the unit I loaned. Thanks for the heads up, that would also explain fuel being back-blown out of the carb after the timing is advanced past about 20* at around 2500 RPM. Dang I really hope not, but so it goes. I’ll update after compression test results.
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dlb
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Re: Need help from Carb gurus with 22r

Post by dlb »

I just remembered an experience I had on a t4 that could be related to your situation.

I had a t4 that I had gone over thoroughly and it was running great. Then one day, it wasn't. It had symptoms similar to what you're describing in your truck. At a loss, I went back and double checked the timing, and it was off from where I had set it. I double checked the distributor bolt and it was snug, so I took the cap off and checked the rotor, and here was the problem: the mechanical advance in the distributor was gummed up with dirty old grease. Normally, you can twist the rotor by hand a bit (sorry, I can't remember which direction) and it should snap back to its original position, but in this case it was hard to twist it at all, and it didn't snap back. So I wasn't able to time it properly to start with, it wasn't advancing properly while running, and it would move a bit while running which made the symptoms change a bit every now and then. I had to disassemble the entire distributor, clean out the old grease, and re-grease it, and then it ran great.

So that's something you can check easily. Just remove the cap and confirm that the rotor can twist a bit and then snaps back.
jmoore
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Re: Need help from Carb gurus with 22r

Post by jmoore »

Right on, when you say snap back into place, the rotor will not turn as under normal engine operations, but instead the shaft will twist a little from the force you are applying, then ‘snap’ back to where it was before you manipulated it? If that’s the case it seems to be clean and free from defect, the entire dizz is about a month old, too. My timing will advance from about 8 at idle until it reaches about 20*, then it will do the purging/sputtering symptom. Does that sound about the same? Still waiting to have my compression testing kit returned... loaning tools- No good deed goes unpunished.
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dlb
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Re: Need help from Carb gurus with 22r

Post by dlb »

Ok yeah your mechanical advance in the distributor sounds fine. And the timing advancing under different conditions is pretty similar to the t4's too so that all seems right to me.
jmoore
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Re: Need help from Carb gurus with 22r

Post by jmoore »

Thanks, compression looks good. 165-175 on all 4 so no bent valves. Scratchin my head still. Probably going to do another deep clean on the carb and let it soak in solution over night before reassembly. I’ll keep the thread updated.
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