Topic: 22RE Surges Under Throttle TPS - SOLVED

[Win243]

I have recently bought a 1985 Toyota Hilux 22RE to build a rock crawler.  The bed has been bobbed 1 foot.

The engine surges badly when 1/4 or more throttle is applied.  It runs well if the Throttle Position Sensor is disconnected.  I tested the TPS with an ohm meter at the TPS itself, as well as at the CPU connection, and it looks OK.  I tested with a noid light, and it is actually cutting the injectors like it was a rev limiter, except at about 2200 RPM.  When the engine slows down to around 2000 RPM it picks up again, and repeats.  There was previously a code for the "Water Thermo Sensor (THW)" being open or shorted.  I repaired this problem and there are no codes now.  I tried another ECU out of my 1985 2wd 1 ton 22RE Toyota, and it has the same issue.

Any help would be greatly appreciated.  Thank you, this is an awesome forum.


EDIT:  The problem was the TPS after all, scroll down for details.

[SqWADoosh]

Remove your throttle body from the engine and completely clean it and the IAC. Then reinstall your TPS and set it up properly with this guide: http://www.4crawler.com/4x4/CheapTricks/TPS/index.shtml if that doesn't do it I would replace the TPS.

[Win243 [OP]]

Remove your throttle body from the engine and completely clean it and the IAC. Then reinstall your TPS and set it up properly with this guide: http://www.4crawler.com/4x4/CheapTricks/TPS/index.shtml if that doesn't do it I would replace the TPS.

I cleaned the TB and bench checked the TPS (it's testing good per FSM specs) and reassembled and readjusted.  I didn't clean the IAC yet, but the cold high idle and lower warm idle functions seem to work.  The problem persists.

[SqWADoosh]

I cleaned the TB and bench checked the TPS (it's testing good per FSM specs) and reassembled and readjusted.  I didn't clean the IAC yet, but the cold high idle and lower warm idle functions seem to work.  The problem persists.

Its very likely the iac

[Win243 [OP]]

The IAC would cause the ecu to cut injectors at ~2200RPM?

Its very likely the iac

[SqWADoosh]

The IAC would cause the ecu to cut injectors at ~2200RPM?

Idle problems and 22RE are almost always either the tps or the IAC. You say your TPS is good so clean the damn IAC. Its not hard and will be checked off the list or solve your problem.

[Win243 [OP]]

Idle problems and 22RE are almost always either the tps or the IAC. You say your TPS is good so clean the damn IAC. Its not hard and will be checked off the list or solve your problem.

I will clean the IAC for good measure, but is not an idle problem.  The truck idles really well. The problem is that the computer is basically "rev limiting" my engine at 2200rpm. That's why I'm skeptical that the IAC is the culprit.

[SqWADoosh]

I will clean the IAC for good measure, but is not an idle problem.  The truck idles really well. The problem is that the computer is basically "rev limiting" my engine at 2200rpm. That's why I'm skeptical that the IAC is the culprit.

Do you have a buddy who's tps you can try? It's not unheard of to have them check out ok on the multimeter and still be bad.

[Win243 [OP]]

Do you have a buddy who's tps you can try? It's not unheard of to have them check out ok on the multimeter and still be bad.

I used my father's (he is a bus mechanic, he used to be a Land Rover tech) graphing volt meter to check the sweep for any spikes or dropouts. I found none. I can try the TPS from my 2wd 1 ton pickup, but I hesitate to. Last time I had it smogged, the tech suggested it might be bad.
I can also try the one from my 1988 4Runner, but I thought they changed the values...?
I'll continue screwing around with it when I get home tonight.
Thank you for the help, SqWADoosh.

[SqWADoosh]

I used my father's (he is a bus mechanic, he used to be a Land Rover tech) graphing volt meter to check the sweep for any spikes or dropouts. I found none. I can try the TPS from my 2wd 1 ton pickup, but I hesitate to. Last time I had it smogged, the tech suggested it might be bad.
I can also try the one from my 1988 4Runner, but I thought they changed the values...?
I'll continue screwing around with it when I get home tonight.
Thank you for the help, SqWADoosh.

If its bad then no amount screwing around with it is going to help. A new one is like $100 if you can swing that.

[Win243 [OP]]

If its bad then no amount screwing around with it is going to help. A new one is like $100 if you can swing that.

Yeah, I'm about ready to just buy a new one and see what happens. I'm hoping I can get the engine running right, soon, because I have plenty of suspension and drivetrain work I want to do to it before this summer.

[OVRAROK]

you say it runs good with tps unplugged, this means its in limp mode. purely running off the afm, sounds like there is a conflict between the tps and afm, I would check wiring from tps, also check for crack in intake tube from afm to TB.i would recheck valve lash, may have a tight intake valve, double check timing

[emsvitil]

The IAC on an 85 is only additional air for cold starts.

The usual failure mode is too high of an idle once you warm up (because the electric heater inside quits)

It doesn't constantly raise/lower idle speed in an attempt to keep a constant RPM like modern  IACs

[Win243 [OP]]

It doesn't constantly raise/lower idle speed...

I hope I'm properly explaining my problem. It's not an idle issue. It's when I apply throttle. Maybe I'll make a video to demonstrate the issue.

[emsvitil]

I was trying to point out that the IAC on a 85 is very primitive and is most likely NOT the problem......

[Win243 [OP]]

I was trying to point out that the IAC on a 85 is very primitive and is most likely NOT the problem......

OK, I'm sorry.  I agree with your logic, I just wanted to make sure I was clear on this not being an idle issue.
Thank you for your input.

[Win243 [OP]]

I apologize for not posting my resolution a few months back,  but the issue was with the Throttle Position Sensor.  Although the old one tested properly with the ohm meter, I changed it anyway.  Problem Solved!
Thank you for the input here.

[OVRAROK]

glad to see a thread that actually ends with problem solved