Fluctuating Idle

[Dragk913]

Ok, I searched on SM but I couldn't find anything like my problem.

Whenever I start the Soup it rev's from 750 to 2500 rpm's, over and over. I wouldn't consider the car to be idling roughly but it's obviously not right.

If anyone could suggest a solution I would be in your debt forever. I had my timing checked so I don't think that's it but I can't find anything on TSRM.


Thanks!

 

[Dragk913]

small update: I checked the ISC and it clicks [about 4 times] after I turn off the engine so it's working, according to TSRM. I also played around with the TPS and I have it set as low as possible.

 

[f00g00]

If you have a multimeter then read out the TPS IAW the TSRM.
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=FI&P=101
Set it and leave it alone. Also manually open it while reading it and make sure it isn't intermittent. A bad signal from the TPS can run the idle up and down with your foot off the gas pedal while at idle. There is a switch inside the TPS that is set at idle so the ECU knows its there.
A large vacuum leak could also cause the idle to fluctuate so listen for a hissing sound.

 

[Dragk913]

If you have a multimeter then read out the TPS IAW the TSRM.
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=FI&P=101
Set it and leave it alone. Also manually open it while reading it and make sure it isn't intermittent. A bad signal from the TPS can run the idle up and down with your foot off the gas pedal while at idle. There is a switch inside the TPS that is set at idle so the ECU knows its there.
A large vacuum leak could also cause the idle to fluctuate so listen for a hissing sound.

Wow. thanks for the link.
I messed with the tps and used a multimeter and the sensor shows to be fine, however the Soup is still throwing code 41 [TPS].

 

[f00g00]

Code 41 for the NA says to troubleshoot on this page,
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=FI&P=36
but did you pull the EFI fuse to reset the ECU? the code will still be stored till you reset it.
Use a feeler guage also when checking the IDL setting.
When my TPS crapped out there was an open circuit when just off idle between VTA and E2 iirc and it caused it to momentarily go into fuel cut and the car would lurch. Real pita in stop and go traffic.

 

[Dragk913]

Thanks for the help f00g00. I went through a bunch of crap but I found my problem: The wiring harness. Some how, during my rebuild, the harness got messed up and now there is no current going through the wires to the TPS.

 

[88YotaTurbo]

have you done any work recently before this happened?
Try checking for an unmetered air leak (after the air flow meter). This happened to me before, my plastic canister in the air pipe melted do to exhaust temp and my ignorance removing the heat shields .

 

[Dragk913]

have you done any work recently before this happened?
Try checking for an unmetered air leak (after the air flow meter). This happened to me before, my plastic canister in the air pipe melted do to exhaust temp and my ignorance removing the heat shields .

Well i just finished rebuilding the engine [and I took off a couple heat shields] but in the end my idle was messing up because of the TPS [the wiring was fine]. I fixed it and the car ran great for about 30min.

Then the car wouldn't start, so I had to give it gas to get it going. If I let off the gas the car dies. I've been playing with different possibilities but nothing is working.
Anyone have any suggestions?

 

[AJ'S 88NA]

It idles ok when you first start it cold? If you've just done a rebuild it's easy to miss a vac line, a connection, or something simple I've done it several times and think I've really screwed up something to find a vac line not connected or the AFM harness not plugged in. Double check all your connections and check to see that your vac. lines are right.

 

[supraman508]

Ok, I searched on SM but I couldn't find anything like my problem.

Whenever I start the Soup it rev's from 750 to 2500 rpm's, over and over. I wouldn't consider the car to be idling roughly but it's obviously not right.

If anyone could suggest a solution I would be in your debt forever. I had my timing checked so I don't think that's it but I can't find anything on TSRM.


Thanks!

I had the same problem with my soup.i had to ajust the acceleration cable.which help alot.try that.

 

[F_T_F]

I had the same problem with my soup.

then go back to the store and exchange it for cambbells chunky.
as for the SUPRA spray starting fluid on the intake maniold to see if you hear the idle jump up. if so then its a vac leak and fix accordingly.