cd92835

I'm driving a 94 pickup with a 22RE...

Recently, the engine began stalling after it warmed up, when I lift my foot off the throttle...
Also accompanied by infamous ECU click.

Took it to my mechanic, got it tuned up, cleaned up and 'happy.'

Runs right and tight when it's cool, but still stalls after it warms up.

Took it BACK to my mechanic had him walk me through the diagnostic...
Compression is good across all four cylinders, but I'm down on POWER in cyl 1 + 3.
He noted the 'miss/stumble' that has been there forever and told me that the smog computer says it's an 'electrical miss,' but it still passes smog (I'm in CA).

Ground is good, NO vacuum leaks, NO OBD trouble codes, NO CEL.

Looks like I'm now at the "let's try replacing this to see if it works" stage...

I've looked at other posts where replacing the TPS or AFM helped solve their problem ... but without a trouble code, I'm thinking probably not.

I'm thinking it could be the Coil or the Distributor.

I'm HOPING it's the Coil, since that's a < $100 part and 30 minute job, and the smog diagnostic points to an electrical problem. But I'm afraid it's the Distributor because it's the original part and it has 205k miles on it. Also cyls 1&3 are next to each other on the physical top of the unit as it sits, so if the shaft has gotten sloppy...

I've got enough $ to fix one problem a month, if I do it myself.
I welcome your suggestions on spending my time and money wisely.

Thanks,

Dave

snobdds

I would turn the idle screw up on the TB when it gets warm. If it stays running than you know to look at the Idle Air Control Valve and the hoses that run from it to the TB. If it dosen't work then return the screw to the origonal position and start check for vaccum leaks.

This is just a check and the idle screw is suppose to be at the point where the idle is at 800rpm when warm...

cd92835

Thanks, I did try that, and it didn't help...

I've since replaced the coil. When I pulled it off, I could see that there was some corrosion through the plates, so I'm happy to replace it just on principle (it was 18+ years old).

However, just yesterday the "Check Engine" light came on, so I'm off to see my mechanic after work to see what the little box will tell us.

I suspect it's the MAF, since it's come on sporadically since I put on the header and K&N fipk unit. That was on the 'fix it' list, and may have just been bumped up.

Anyone even crack one open to look?
Or is just to 'pull out and replace' job?

ALSO, the unpredictable 'miss' that the smog tester said was electrical, still shows up at higher rpm, but noticeably less often... anyone think it could be the Ignitor?


I hate bugging my mechanic to try to figure sh-t out that I can't afford to pay him for (he's a friend, so it's kind of a quid pro quo)... I really appreciate any suggestions.

NickB47

I'm pretty new here, but I have read a few things about the distributors on these vehicles doing some strange things when they start to wear out. Not what you want to hear I am sure. Maybe try a search on 'how to test the distributor' or something to that effect.

Based on your description I initially thought it was the coil, but if you have replaced that... there are enough sensors on these things to keep one guessing. Maybe your cold-start injector timer is kaput causing it to bog out when it warms up??

Can you start it right away after it stalls, or how long do you have to wait for it to fire up again?

cd92835

""Maybe your cold-start injector timer is kaput causing it to bog out when it warms up??""

Thought of this, but it runs just fine after it warms up, until I lift my foot.
The engine wants to die but if I keep my foot on it lightly, it will run, and even smoothly


""Can you start it right away after it stalls, or how long do you have to wait for it to fire up again?""

I can start it up immediately.

I'll run that search you mentioned, as I haven't heard anything specific, but short of replacing all the electronics, branch by branch, I'm kind of heading that way already... I'd like to think it's something else, but I'm running out of options.

NickB47

Maybe some searches for TPS, high/low idle, etc...

Teuf

I know, I am trying to revive this. Have you tested your sending units.

cd92835

Thanks for this Teuf ~

Don't sweat reviving it, I'm short of work now, so nothing is happening fast.
Since it's drivable I'm just babying it and working through the free and "cheap" fixes as I can.

I was just talking this thru with a buddy on Wednesday.
He's got to scrounge up the tools, but I'm going to take an afternoon and take it out to his place and test the sensors and sending units. Turns out he's facing a similar mystery with his GMC. Maybe we'll kill 2 birds with one stone?

Thanks again!

scope103

Are you sure the idle is set correctly? If it runs fine cold, and warm with a little throttle, but slows and stops when you take your foot off the pedal, inching the idle up may be all you need. But guessing is bad; you need a tachometer (the one in your dash is okay, but really hard to tell the difference between 850 and 750). http://www.harborfreight.com/lcd-aut...kit-95670.html

Gamefreakgc

I had a similar issue with my 91 P/U earlier this year. I had bad idles when my engine was warm but with no CEL.

For the time being, you can crank up that idle speed so it doesn't die at stops. Not a permanent fix but if you can't get to it right away at least it'll run ok. A good way to check to see if it's a wiring issue is to unplug the TPS and see how it runs. This SHOULD throw the TPS code, if it doesn't you've got a wiring problem (mine also idled at +500 RPM higher)

My old TPS was shot but didn't throw a code so I had to order a new TPS. Get yourself an ohm meter since you'll need it either way if you're trying to adjust the old one or putting on a new one. You can sometime adjust the old one but this didn't work for mine since it would not line up right with the specs. You "adjust" the TPS by rotating it on the Throttle Body, testing the circuits, adjusting, testing, etc. until you have all the areas within the FSM specs. You'll need a gap thickness gauge thingy... forgot what it's called but it's a bunch of thin blades with thickness measurements that you'll insert to slightly open the TB. Keep doing this until it all lines up then plug it back in (a little electric grease doesn't hurt, especially in any connections look corroded).

For the specs, see the below links for a 93 22RE P/U FSM:
http://personal.utulsa.edu/~nathan-b...34throttle.pdf

P.S. Buy a Denso TPS if you need a new one! I tried a cheap off brand and it fried itself in 3 days. Waste of 5 hours of my time and the hassle of returing it. Learn from my mistake. AutoZone and Napa sell Denso ones but shop around, you can get them for ~$90.

maachine

idle air control sensor could be bad. i doubt it's the MAF. usually when it goes bad it doesnt affect anything really. i've dealt with a few different cars with a bad MAF and none had the symptoms you are talking about. on my '02 tacoma my MAF sensor went out. i pulled the sensor out and sprayed it down with carb cleaner. doesnt throw the code anymore.

cd92835

Working thru the helpful suggestions, thank you all.

First thing I did was raise the idle, it hasn't helped.

When it cuts out -which it will do when warm even while cruising if I lift off the throttle - there is a *click* from the passenger footwell, where the engine MCU is located (ECU). It will not always die, but the *click* lets me know that it wants to...

When I can start checking sensors/sending units, I'll begin with the TPS, just because it seems most closely related to this problem. Once I clear that, or fix it, I'll move into another branch.

I'm going to try your trick maachine, maybe that will fix it, or just simplify the search and let me cross that off the list - FOR FREE. I hate having no money.

cd92835

Gamefreakgc ~

I can't load this link through ANY browser, can you provide a bit.ly or other shortened URL? I'd really like to pull those specs.

For the specs, see the below links for a 93 22RE P/U FSM:
http://personal.utulsa.edu/~nathan-buchanan/93fsm/engine/34throttle.pdf


Thanks!