what the hell!

[super.secret.supra.club]

wassup ladies and gents. i come from socal and ive got a problem. well actually, we all do.

anyways here it is. my idle is some what great. (not really) it bobbles from 1000 rpm to 800 then back to 1000 and so on. its constantly like this. thats the first problem.

second is, the rev is great nothing really wrong with it until i let go of my gas pedal. lets say i rev to 3000 and let go. the rpm go down like you would expect but intead of returning back to normal idle mine just keeps going down until the engine dies.

third is that my boost doest seem to be hitting 8 pounds which is stock setting. i can only get to about 7 pounds. my BOV (hks ssqv) is not as loud as it used to be.

now for me putting 1, 2, and 3 together makes me think of a vacuum lead somewhere.

and finally my questions? has this ever happened to anybody here? where would be a "first place to look"?

you opinions and help are well appreciated

 

[jetjock]

We all have a problem? How is that?

The first place to look would be the TRSM. The second would be at the CEL with the diagnostic jumper in. Your symptoms indicate a possible lack of ISC system activation because the TPS is not adjusted or bad. If you get a code 51 with the throttle closed that would confirm it.

Finally, the boost spec is not 8 psi. It could easily be a little less with everything normal.

 

[super.secret.supra.club]

We all have a problem? How is that?

The first place to look would be the TRSM. The second would be at the CEL with the diagnostic jumper in. Your symptoms indicate a possible lack of ISC system activation because the TPS is not adjusted or bad. If you get a code 51 with the throttle closed that would confirm it.

Finally, the boost spec is not 8 psi. It could easily be a little less with everything normal.

ok well fist off im kind of a newbie at acronyms. i would think that you might have misspelled TRSM and should be TSRM. what is CEL. i did jump it and it through out code 51. last night i went to change out my TPS that was on a 87 N/A. part numbers matched so i didnt think it would matter. i did the adjustment and everything but i soon as i started my car the idle didnt bobble around as much. but revving thing got worse. before changing out the TPS i would rev and the rmp would go to as low as 200 and then jump to 800 or so. and now the engine just dies. doesnt even stutter anymore.
is it possiple that both TPS are bad? what else should i check for?

 

[mk3ftMFw]

TSRM = toyota service and repair manual. Search the forums and you will find the online version laying around somewhere.

 

[super.secret.supra.club]

TSRM = toyota service and repair manual. Search the forums and you will find the online version laying around somewhere.

yes...thank you for that mk3...that one i knew already....but still thnks

 

[jdub]

CEL is "Check Engine Light"...follow JJ's advice on the idle problem. He is the site expert on the stock ECU...pretty sure he knows what he's talking about

You may have a small boost leak causing problem #3. Check all your piping from the turbo to the throttle body. However, 7 psi is normal for a stock turbo.

Double check for a code 51. Your ISC valve may also have excessive carbon deposits. You can disassemble it and clean. Suggest testing both according to the TRSM.

If you have the SSQV vented to the atmosphere, it will make problem #2 worse...it causes a momentary rich condition that kill the motor. *Sometimes* pulling the EFI fuse for a couple minutes (in the box under the hood, behind the battery) to clear ECU memory will allow it to re-learn driving conditions and minimize the problem.

BTW - TRSM is the acronym you will see on this site that references the manual.

 

[jetjock]

Vacuum lead? Fist off? "Through out"? Lol...you've got balls, I'll give you that. I'm usually a stickler for spelling but TSRM occasionally trips me up because nowhere on my copy is that written. Just says Toyota Repair Manual but since the online copy says TSRM I'll concede. As for CEL the irony is I normally don't use that term but decide to because I felt you might not know the correct one. Oh the pain.

As for "our" problem, follow jdub's advice. Double check code 51 isn't there with the throttle closed and inspect the idle speed control path. Any TPS with same part number should work. In fact there's a couple of TPS numbers that will work on your car. If it were me I would've tested the second one before installing it. Hell, I would've checked the first one before even messing with the second one. If you're venting the BOV to atmosphere that's also likely to be a problem.

Even though I'm tired of pointing this out I'll do it again: People accord the TPS far too much driveability importance. It needs to be working for a correct idle and there is a particular (but very rare) type of way it can fail that'll cause a specific idle symptom but otherwise you could drive the car all day long with it disconnected.

Put another way it's contribution to how the engine runs is large when the throttle is closed but minor at other times. I see way too many off-idle problems wrongly blamed on the TPS. While the off-idle portion performs many functions the only *driveability* symptom that should point to it is a slight stumble upon rapid acceleration while under load. If you suspect it as the cause of other off-idle problems the odds are overwhelming you're barking up the wrong tree.

Having said all that said in your case it needs to be checked because your complaint concerns idle.

 

[super.secret.supra.club]

ok well i did the jumper and its still giving me code 51. i pulled out EFI fuse to reset the ECU did the jumper again and still code 51. i had also checked both TPS and they seem to be fine.
i also cleaned out the thottle body. i was afraid it was sticking.

and now im stuck. and yes jet jock i do have balls. thank you :icon_bigg
and yes... im not that great in typing or spelling. so please excuse my typing.

 

[supraguy@aol]

It might be a wiring issue to the TPS... HTH