Cutting out if I ease off the gas UPDATED, PLEASE HELP

ForcedTorque

Join the 92 Owners Group
Jul 11, 2005
6,097
2
38
58
Satsuma, Alabama, United States
I have been working on this car for a long time with little knowlege. Here is a little background. I still have a few issues with the car that will make diagnosing this difficult I know.

It's a 92, but I converted a 89 wiring harness to fit this car.

Still have no Check Engine light

Have no Tach

Idle is not perfect, but is now better than it has ever been. It will idle fine most of the time, although a bit high. Sometimes it gets high enough to cut fuel, and drop the idle (1700 I think). This doesn't happen as often as it used to, but I wonder if it is the cause of the current problem.

OK, so the car runs pretty good now. So far, it still is limited to driving around the neighborhood. I try to keep the drives calm, but I've done a little while kids are in school. If I am accelerating, everything is fine. But, if I ease off the gas to a point that I'm not accelerating, it will cut fuel. I take my foot off the gas for a second or so, and it will come right back. If I nail it, it will not cut out. I've done a good bit of testing on this. It only happens when I have reached my desired speed and try to just maintain it.

My thoughts are, it's either TPS related, or due to the harness not being right. I've planned on replacing the harness for a while, but unemployment hasn't made that possible yet. I believe it to be the source of all of my problems. But, I want to know if maybe there is something else that may be causing this particular issue.
 
Last edited:

ForcedTorque

Join the 92 Owners Group
Jul 11, 2005
6,097
2
38
58
Satsuma, Alabama, United States
I had hernia surgery Thursday. I'm gonna try to set the TPS as soon as I feel like climbing in and out of the car again. i have to go buy a battery for my multimeter before I do it though.

Any other suggestions?
 

ForcedTorque

Join the 92 Owners Group
Jul 11, 2005
6,097
2
38
58
Satsuma, Alabama, United States
***UPDATE***

I adjusted the TPS today, and it brought the car to life. However, the idle is still high. The original issue that started this thread is gone, I think. It may be just in hiding, disguised by the higher idle. My tach does not work, so I have to guess. I believe idle to be between 1500-2500. It is not cycling, which happens around 1700, but it seems to be a little higher than that (maybe alot higher).

I had the throttle body off while trying to set it the first time. I know that it rests at closed. I took off the throttle rod, trying to see if maybe it needed adjusting, but it made no difference. Is there anything else I can do to lower the idle? Could pulling the EFI fuse help?
 

IndigoMKII

New Member
May 9, 2011
2,181
0
0
Madison, Virginia
I suggested this in your build thread, setting the ignition timing brought my idle down quite a bit. The fuel cut rpm is 1600-1200 according to the TSRM. It's 1800-1200 on a 7mge.
 
Oct 11, 2005
3,815
13
38
Thousand Oaks, CA
Block or pinch the hose to the idle speed control valve and see if it stalls (it should). If it doesn't your throttle body (or possibly pcv if its been modified) is letting too much air in. Make sure the throttle is is not gunked up and the plate is closing fully.

You might also want to verify the ISC is operating properly and not stuck open. The ECU will set no codes if the ISC is unplugged.