jon L Posted July 19, 2021 Share Posted July 19, 2021 (edited) You may remember last year when I couldn't get my car to idle at the correct speed. I did find and repair the problem. (broken wire in the IAC circuit) Now it seem to have developed a new idle problem. Now starts up very quickly, idles fast and then goes to a normal idle. Running in neutral i think it will run for quite a while. In gear it will idle for a few minutes and then suddenly die, like you shut the key off. It starts right away and idles normally. When driving, it runs great, but stop for a light and it will die, but not all of the time. I am at a loss trying to find the problem. Any and all help would be appreciated. Has anyone ever had a power steering sensor go bad? My last idea. Jon Edited July 20, 2021 by jon L Link to comment Share on other sites More sharing options...
DAVES89 Posted July 19, 2021 Share Posted July 19, 2021 Never had the power steering sensor go bad, but I always thought that sensor was for the A/C cut off when making a turn. Link to comment Share on other sites More sharing options...
2seater Posted July 19, 2021 Share Posted July 19, 2021 I don’t have any great insight on this particular set of circumstances but I had a crank sensor failure that acted in a somewhat similar way. Eventually it wouldn’t start but after cooling a bit, it would. It ran perfectly but would shut off for no apparent reason. The major difference is mine eventually wouldn’t restart but always did after cooling. Link to comment Share on other sites More sharing options...
Padgett Posted July 19, 2021 Share Posted July 19, 2021 I had a Fiero that did same. Turned out to be a bad TPS wire that went to zero on a stop. What is the TPS reading doing ? ED01. Link to comment Share on other sites More sharing options...
jon L Posted July 20, 2021 Topic Author Share Posted July 20, 2021 (edited) .46 TPS It doesn't die every time I stop. And occasionally when started the idle is fast. I shut it off and restarting it idles normally. Edited July 20, 2021 by jon L Link to comment Share on other sites More sharing options...
RLTherio Posted July 27, 2021 Share Posted July 27, 2021 What is the ideal voltage setting for the TPS at idle? Link to comment Share on other sites More sharing options...
Padgett Posted July 27, 2021 Share Posted July 27, 2021 .38-.42v Link to comment Share on other sites More sharing options...
jon L Posted July 28, 2021 Topic Author Share Posted July 28, 2021 What is the comparison between the two voltages.? I mean, lower voltage lower idle? Or higher idle? Link to comment Share on other sites More sharing options...
2seater Posted July 28, 2021 Share Posted July 28, 2021 As far as I know, it doesn’t have a direct connection or control of idle but is an indicator used by the ECM. The ECM can adjust within a range for most readings but there are limits to the amount of latitude it has. When the overall system is running, inputs are expected within a programmed range or an error code will result. Link to comment Share on other sites More sharing options...
Padgett Posted July 28, 2021 Share Posted July 28, 2021 (edited) That is the range. Anywhere between .38v and .42v is OK. Should also be over 4v at WOT. A bad wire causing the signal to drop to zero can cause the engine to die. A high value makes the computer think your foot is on the gas and will idle up. Edited July 28, 2021 by Padgett 1 Link to comment Share on other sites More sharing options...
jon L Posted July 29, 2021 Topic Author Share Posted July 29, 2021 Thanks guys. I'm working on it. 1 Link to comment Share on other sites More sharing options...
jon L Posted August 3, 2021 Topic Author Share Posted August 3, 2021 I have reset the TPS to .42 and it seems to idles better. This afternoon I am taking it to a cruise and will report tomorrow. 2 Link to comment Share on other sites More sharing options...
jon L Posted August 5, 2021 Topic Author Share Posted August 5, 2021 So, I took it out last night to a cruise. It ran fine, no problems, until I pulled in to my driveway, stopped and opened my garage door from the street. It then proceeded to die. In gear, idling. It started right up sand did not die again. ??????????? Link to comment Share on other sites More sharing options...
Ronnie Posted August 5, 2021 Share Posted August 5, 2021 Those kind of random problems can be really hard to find. All you can do is check everything you know to check, ICM, IAC, fuel pressure ect.. I know you have checked all that so I can't help wonder if it's something related to the supercharger? It would be much easier to fix if it would just quit and not restart. Link to comment Share on other sites More sharing options...
Padgett Posted August 5, 2021 Share Posted August 5, 2021 Did it just stop or slow then stop ? Link to comment Share on other sites More sharing options...
jon L Posted August 7, 2021 Topic Author Share Posted August 7, 2021 The idle drops 750 then drops a little lower and then dies. Where should the screw on the throttle body set at? To completely close the throttle plate, or partly open? Link to comment Share on other sites More sharing options...
Ronnie Posted August 7, 2021 Share Posted August 7, 2021 There might be a specification for that in the FSM but I don't know where it would be. I think the throttle plate stop (screw) should be adjusted so the throttle plate is closed as much as possible without the plate sticking in the bore of the throttle body. The IAC has a passageway the routes air behind the throttle plate to supply the air needed at idle. That is what should be controlling the idle speed, not the throttle plate. 1 1 Link to comment Share on other sites More sharing options...
Padgett Posted August 7, 2021 Share Posted August 7, 2021 "The idle drops 750 then drops a little lower and then dies." - that sounds like a dirty IAC. See here. 1 Link to comment Share on other sites More sharing options...
jon L Posted August 7, 2021 Topic Author Share Posted August 7, 2021 It does, but it's clean and new. Link to comment Share on other sites More sharing options...
Padgett Posted August 12, 2021 Share Posted August 12, 2021 And did you clean out the passages ? They can get gunked up too. Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now