The other day while driving the idle started to fluctuate from 1500 to 2200 and would just keep repeating. Then out of no where it would go away, but then come back a short time later..mods are in sig. Any help would be greatly appreciated. Thanks!
Help weird idle
- Thread starter 89supraa
- Start date
Did you see if there were any check engine codes. It could be your tps. Mine was idling at 1500 rpm and my tps spring was stuck. What you can do is unplug the tps and see if anything changes. I unplugged mine and drove it down the road and it stayed at 1500 at idle. Make sure you check those engine codes first thing.
Crazy: Your problem was likely a vacuum leak, The surging is the TCCS limiting idle speed (fuel cut) so the engine does not idle at too high of an RPM. The TPS has a switch in it to tell the TCCS when its supposed to be at idle. Unplugging the TPS opened those contacts stopping the TCCS from preventing a fast idle.
I keep saying it but nobody listens: Vacuum leaks do not cause an idle speed increase on Type L EFI systems...
Wrong. Go unplug your tps and see what it does. I took my tps off and the spring on it was rusted up not allowing it to fall back in the rest position. I took some wd 40 and kept working it and it freed right up. FWIW.
Are you replying to me? I wasn't talking about the TPS. However I'm more than familiar with what it does and what happens when it fails...
Crazy: So it was holding the throttle body open at a constant engine speed? Definitely a strange occurrence, though different from a surging issue. Never would think a TPS would rust holding the throttle plate open.
Jetjock: I understand it would cause a major lean condition from unmetered air, Would the be the reason or is there something else?
Jetjock: I understand it would cause a major lean condition from unmetered air, Would the be the reason or is there something else?
Yes it was. I could actually tap on the tps while it was idling and the rpms would start dropping. That might be something he should try to is to lightly tap on the tps. First check the engine codes.
Crazy: Oh, ok. Threw me there for a second. My take on his post was that unmetered air would raise idle speed enough to hit rpm cut because IDL was closed. That can not happen, at least not on a stock 7M. He's otherwise correct.
Chunks: I dunno what his problem is. I was just pointing out the "vacuum leak = idle speed increase" thing needs to die. It's true for Type D systems but not for Type L. As you pointed out pirate air on these systems effects mixture (idle quality) not speed. For speed to be effected the "leak" would have to be metered bypass air.
Chunks: I dunno what his problem is. I was just pointing out the "vacuum leak = idle speed increase" thing needs to die. It's true for Type D systems but not for Type L. As you pointed out pirate air on these systems effects mixture (idle quality) not speed. For speed to be effected the "leak" would have to be metered bypass air.
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JJ: The vacuum leak thing was what i was inquiring. I figured it was the lean condition, After i thought about it i don't know why i posted that.
Because you're a smart guy (I've read enough of your stuff to know that) and even smart people make mistakes...
There may be codes without the check engine light being on.
First Bookmark This website http://www.cygnusx1.net/Supra/Library/TSRM/MK3/default.aspx
Second Start diagnosing here. http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=FI&P=23
Jetjock: Humans will be humans i guess. Would be cool to be part machine like terminator sometimes though.
First Bookmark This website http://www.cygnusx1.net/Supra/Library/TSRM/MK3/default.aspx
Second Start diagnosing here. http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=FI&P=23
Jetjock: Humans will be humans i guess. Would be cool to be part machine like terminator sometimes though.
alright guys, went to check the codes and i had never noticed it before but my check engine light does not come on at all,so today since its nice i am going to pull the cluster out to see if the bulb is burnt out or if the previous owner was shady and took it out.. thanks for the info nosechunks
alright, the copper contact points were a little dirty so i cleaned up up a bit now the light works. i got 3 codes 34-turbo charger pressure,41-throttle position sensor signal, and 43- starter signal. I am guessing 34 comes up because i have a boost controller set to 8. Thank you again everybody
ok, so i went and got a new tps because mine was all beat up anyways, calibrated it according to tsrm, that worked for about a week. now It started doing it again today after the intercooler pipe that connects to the turbo outlet popped off. Got a different set up on there now,boost leak tested, system is strong. smells like its burning oil, and the turbo sounds bad when i shut the car off like its scraping internally. theres hardly any shaft play only a very little side to side none in and out. Checked the oil and it was good?... Im getting a little scared that maybe the oil lines to turbo are clogged.
Define the scraping internally sound? Maybe try taking the intake hose off the turbo inlet and spin by hand to see if it makes the same noise?
If changing the TPS worked once then check it for calibration again. Maybe something is up with it, or its wiring.
If changing the TPS worked once then check it for calibration again. Maybe something is up with it, or its wiring.