vinman33

Hey Guys,
I have an 1986 Toyota sr5 xtra cab 22re 4x4 (5 speed) with 241 on the clock. All stock, newer LCE timing chain/guide and somewhat recent tuneup with denso 02 (past 5 years)

The truck start perfectly and idles pretty good and will rev in neutral excellent, but once in gear and trying to accelerate it hesitates/stumbles enough to notice.

I did the diagnostic check and it came back as code 11 = ECM/ECU?

I do have some water on the passenger footwell when it rains but i fixed that with RTV years ago.

Just not sure what else to check? Could it be the ECU? or clogged cat/fuel filter? i was thinking cat/fuel filter is fine because it revs just fine in neutral.

Any help or suggestions would be great!

Thanks
Vinny in PA

vinman33

So tonight on the way home from work 8 miles, i was tired of the stumbling and wanted to try and see if unplugging the EGR would make any difference. So i pulled over and shut off the truck unplugged the EGR, started the truck and drove the the rest of the way home without any issue, no stumble and no CEL. So does that mean the o2 is bad or might i have another issue that is being masked by me pulling it? Any harm in driving this way forever? I dont need emissions stickers since i drive less than 5K a year in PA.
What do you think?

Thanks!

kelvinb

any specific rpm it hesitates? mine does something similar but i got rid of my egr system. ive noticed 2/3rd gear between 2-3k rpm it does this, if i floor it, it goes away. it really only does it within the first 20 minutes of driving it. after that it doesnt do it. i have no CEL, but im guessing its my TPS, ECU, or something else i have yet to diagnose.

vinman33

It does do it more between 2&3K rpms but its there all the time. Flooring it in my truck does nothing unless i downshift to second (manual).

I ordered new Desno O2 and will see if that helps. I think my ECU might be rusty from the water dripping on it from leaky windsheild.

kelvinb

only other thing i can think of that may be an issue is the AFM. im going to swap mine out and see if it changes anything.

vinman33

Ok I put in the new O2 sensor and it still does the same thing as the old o2 sensor. Once the engine is warm is has the hesitation and slight bucking. with the o2 sensor unplugged it runs pretty good for an old truck.

So with no o2 sensor it runs fine then that means the fuel pump and fuel pressure is good as well as TPS, MAF and EGR. If those items were bad then it would run bad with or without the O2. So could it be the computer (ECM)?

I love this truck but kinda tired of this issue. I may just run it without an O2 sensor, I mean what could happen, right?

ugh
Vinny

kelvinb

I would try swapping the ecu. I know there are different ecus, and I know some are compatible. I would try and find one that matches yours.

Kiroshu

^--- Its right there in that post. If you had stumbling and hesitation on acceleration underload, and unpluging the EGR valve's vacuum source made it go away then you have just diagnosed your problem.

This means you have a faulty egr system more than likely the egr valve was opening too early and or stuck slighty open possibley even an internal leak.

Lots of people run there trucks without egr its not really a big deal unless you live in an emissions strict area.

Same thing happened to my 4runner. Egr valve has been unplugged for years. I plan to fix it when I refurbish the engine one day haha.

If you want repair this issue. Replace the EGR valve and vacuum modulator for egr and clean/inspect all egr passages.

vinman33

Hey thanks for replying, I do appreciate it alot!
You mentioned the EGR when i was talking about the O2 sensor? Or are you suggesting that it is in fact my EGR thats bad? I put in a new egr two years ago but i did NOT clean any passages that may go to the egr, I didnt think i had to but i guess ill look at that and the ECU in the kick panel.

Thanks
Vinny

RJR

Hey vinman33, Kiroshu is referring to your second post, where you say you unplugged the EGR and the problem went away. From then on you talked about tinkering with the O2 sensor. Why??

If indeed it was unplugging the EGR that made the problem go away, that's the subsystem you should be working on - forget about the O2 sensor for the time being.

If, on the other hand, in your second post you actually mistakenly wrote EGR instead of O2 sensor, then you've managed to confuse us all with bad information.
Please clarify what you really meant to say.

vinman33

Oh gosh my apologies!
I meant O2 not EGR. I never unplugged the EGR, only the O2 sensor. my bad no mas!

Please forgive!

Vinny

RJR

Thanks for clarifying. That'll help us all focus in the same direction. Sounds like a mixture problem to me. Could mean the AFM needs adjusting. You'll probably want to put a digital multimeter on the O2 sensor output and see what it's doing at idle and at 2500 rpm (make sure it's warmed up good.) It should be switching between 0 and 1V around once/second.

Kiroshu

Wow.

So unplugged Oxygen Sensor remedied the problem..? Interesting.

As stated above. Its possible it is an air/fuel ratio issue.

Faulty Oxygen sensor..?

Air Flow Meter as stated above is definatly a good investigation area as well.

Verify good/clean/tight electrical connections and engine management electronics.

A ECM fault for the oxygen sensor circuit is possible.