I've been having a problem w/ my 87GT where it would fire up and then it would idle so low that it would just cut off. last night i removed the throttle body, cleaned it out really well and then installed it with a new IAC. Fired up the car and it started right up, but then it started idling erratically like i was sitting in the car pumping the gas pedal. if anyone could give me some suggestions of what to look at next, it would be greatly appreciated. thanks

I'm just a hack here but I'd probably start at the ECM and check the codes. Are you getting an engine light?

I'd start by checking your TPS is not erratic on it's output, the CTS is reading correctly, and the Map output is working correctly.
All three can be checked out somewhat with a volt meter. (ohms for the CTS)
Winaldl would make it easier.
While you where cleaning the Throttle body did you do the finger over the IAC port to check for vac leaks.

quote Originally posted by Dodgerunner: I'd start by checking your TPS is not erratic on it's output, the CTS is reading correctly, and the Map output is working correctly. All three can be checked out somewhat with a volt meter. (ohms for the CTS)

would it be possible to get a better description on how to do this? i looked in the search and couldn't really find anything. what is meant by CTS and what is the Map Output?

quote Winaldl would make it easier.

where can i get this?

quote While you where cleaning the Throttle body did you do the finger over the IAC port to check for vac leaks.

i did not..how do you do this?

sorry for the lack of knowledge and all the questions...and thanks for the help

Might start by reading this post, lots of ideas and tips. https://www.fiero.nl/forum/Forum2/HTML/077235.html

1. As Sundowner said. Just the AB pins of the ALDL connector and see if it flashes any codes.
https://www.fiero.nl/cgi-bin/main.cgi?ECMCodes

2. Checking CTS. https://www.fiero.nl/forum/A...090219-2-083253.html
http://s20.photobucket.com/...ent=CTSMAT-chart.jpg

3. The MAP is on the top right side of the intake. Small square block with a plug and vacuum line off the bottom.
You can measure off the middle pin to ground and read the voltage the map outputs to see if it is changing. Little hard to do without a good engine load just running still. http://www.robietherobot.com/storm/mapsensor.htm
Puts out 0-5V depending on engine load.


Winaldl requires you make or buy a cable to connect. The software is free.
http://winaldl.joby.se/
https://www.fiero.nl/forum/Forum2/HTML/069590.html

Eric Idle? Couldn't resist...

quote Originally posted by CarverToo: Eric Idle? Couldn't resist...

you really should have tried

[This message has been edited by labbe001 (edited 08-19-2009).]

quote Originally posted by Dodgerunner: I'd start by checking your TPS is not erratic on it's output, the CTS is reading correctly, and the Map output is working correctly. All three can be checked out somewhat with a volt meter. (ohms for the CTS) Winaldl would make it easier. While you where cleaning the Throttle body did you do the finger over the IAC port to check for vac leaks.

DR, how do you check the TPS voltage output with an multi-meter?? I hope you don't have to splice into the wires to find this out...

BTW, which of the 3 wires do you need to touch to find out the voltage output??

I have a new TPS on my V6 fiero, but its not an AC Delco unit. Just want to see if it matches closely with the correct AC Delco TPS sensor.

Thanks,

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fierogt28

88 GT, loaded, 5-speed

https://www.fiero.nl/forum/Forum2/HTML/081601.html