Stalling Supra

[djairam]

nI'm really hoping that you will be abele to help me shed some light on a problem I have been having. It started as a mild "hiccup" while driving an 88 turbo supra. Had just bought the car and the problem didn't seem to be such a big deal. It felt as if for a split second the engine would stop or stall while cruising. Talked to previous owner who said that the problem began after getting some bad gas. Problem became more frequent and even got to the point where car sometimes stalled at idle or wouldn't start. Changed fuel filter, shop mechanic insisted I needed a new fuel pump. Changed fuel pump, problem reamained continuing to worsen. Cleaned throttle body, thought problem had gone away, it persisted. Now I suspected the MAF may be bad, as problem seemed to go away for a few days after cleaning throttlebody. Replaced MAf with used one on Ebay, problem persists. Some guy that says he knows about these cars says that my TPS checks out, but I'm not really sure he knows what he is talking about. Now the car starts bucking or stalling during acccelaration at about 2500-3000 rpm. Check engine light is on, don't know how to read codes. Check engine has always been on though, even when car ran much better. I'm running out of ideas and money. Could you please send any ideas to djairam at yahoo. thx.

[bigdoggbmx]

check befor all that your wire harness is ok that means that you have too strip all the tape off becouse the heat that is generated in that motor it makes all the wires briddle mine had six broken wires that threw codes that my maf was bad and my knock sensor and well you can see from there
if that is not the problem than check the TPS there pretty cheap if you need one and dont want too spend a lot there about 150$ new i have one ill sell you
hope this helps

[ddmcse]

i think you have 2 issues one is the wiring gremlin mentioned above that will drive you crazy
and i think the other is simply FCO

FCO is caused by the computer checking conditions and detecting that you made modifications to either the intake or exhaust allowing more air flow than japan thinks you should have . if this happens the engine cuts out for a split second and then resumes . if you aren't used to this you could think it's not normal and/or you could crap your pants

[djairam]

Since my post I have been able to read the codes. I am getting a code 52 for the knock sensor. Have gone over some of the wire harness looks ok so far. I know the knock sensor retards the timing but can it cause such a dramatic drivibility problem? The car actually starts to buck @ 2-2500 rpms, until you let off the gas. If you punch it and it gets past 3k, all is good. Additionally, after resetting the ecu, it was doing this with no check engine light on. This thing is driving me nuts. Off the subject, I have one other question, one day I shut the car off and when I started it again my speedo didn't work. Everything else on dash is fine, just the speedo. Any body seen this before?

[dcrusupra]

Probably a bad speedo cable. Have you checked the flow on your injectors? They could be clogged.

[bigdoggbmx]

dont know if you have fixed your problem but
do bench tests on iacv this is what was wrong with mine it caused it to only
go 2-3000 RPMs look at that too

[djairam]

I don't what happened but here's how it went. Problem continued to persist, if anything, getting worse, bucking and stalling. Needed some gas, put super in in instead of regular. It started acting up, and I just got pissed and just beat the snot out of the car the whole way home 1/2 hr. That was days ago and the car hasn't acted up since. Still have a code 52 for the knock sensor, but the car runs great now. I can't figure it out.

[ravenmaster]

Hmm this is interesting and what surprises me is noone told you to look at the tsrw or the Haynes guide. What I have been able to gather from what I have read and from talking to several of the guys at my club last night it might be the following:
1. Ignition Timing Incorrect
2. Spark Plug(s) have become faulty or incorrectly gapped, This was one of the things everyone agreed on that is part of the problem. While your at it check the wires.
3. Distributer Cap, take it off and check it for cracks, holes, whatever.
4. Vacuum Leak in the exhaust manifold.
5. Your ECU <- the other -popular answer
My opinion:
Since the -problem came and then suddenly stopped worries me. Toyota's just don't do that unless a serious problem is coming up. I am going on a limb here but I take it that you didn't actually do anything to the knock sensor except for pulling the negative cable off the battery. The fact that the error did came back shows one of two things, and either way I would rep-lace the knock sensor(s) anyway as well as the wiring to the ecu, and in answer to your question a faulty knock sensor can/will have an im-pact on your performance eventually.
Anyway Here is what I believ to be wrong:
1. The wiring between your knock sensor and the ecu is bad/going bad and is fluctuating in its connection hence the knock sensor warning turned off and has stayed off.
2. Your ECU is bad, This would explain the knock sensor re-port as well as the bucking jumping -problem.

Basically go print out/buy the TSRM AND the Haynes Manual. And then check all the stuff mentioned here. I suggest picking up a OHM Meter and a Voltometer too. Its amazing what those things can do.

[tellfromchico,ca]

ive had similar problems possibly check out all of intercooler piping and intake pipe for leaks that would cause a bypass of the maf sensor.

Originally Posted by djairam

nI'm really hoping that you will be abele to help me shed some light on a problem I have been having. It started as a mild "hiccup" while driving an 88 turbo supra. Had just bought the car and the problem didn't seem to be such a big deal. It felt as if for a split second the engine would stop or stall while cruising. Talked to previous owner who said that the problem began after getting some bad gas. Problem became more frequent and even got to the point where car sometimes stalled at idle or wouldn't start. Changed fuel filter, shop mechanic insisted I needed a new fuel pump. Changed fuel pump, problem reamained continuing to worsen. Cleaned throttle body, thought problem had gone away, it persisted. Now I suspected the MAF may be bad, as problem seemed to go away for a few days after cleaning throttlebody. Replaced MAf with used one on Ebay, problem persists. Some guy that says he knows about these cars says that my TPS checks out, but I'm not really sure he knows what he is talking about. Now the car starts bucking or stalling during acccelaration at about 2500-3000 rpm. Check engine light is on, don't know how to read codes. Check engine has always been on though, even when car ran much better. I'm running out of ideas and money. Could you please send any ideas to djairam at yahoo. thx.

[djairam]

The bucking stalling problem is back and I am now getting codes I never got before, 14, 42, 43, 52,
The speed sensor I understand because one day the speedo suddenly didn't work anymore, with out any indications there was a problem. Anyway, I am really starting to believe it's the ECU. Is there anyway to definitively rule it out? The TSRM seems to pretty much just suggest trying another one. What about the camshaft position sensor. The problem is much more predominnat after driving the car a while.