89 GP idles bad

[hockeyguy]

I have a 89 Grand prix with a 2.8 that idles bad after warm up.
SES on, stored code is a 45 (too rich). I have replaced the TPS and the O2 sensor. I have unplugged the vapor canister but I can't seam to find the canister control purge valve and cleaned the IAC and the housing for the IAC, none of these things has helped. The engine idles normally on start up but you can smell that it is running rich and after warm up (when the computer is adjusting for the rich mixture) that is when the idle starts to fluctuate from 1000 down to 500 RPMs.

I am banging my


Please help!!!

[GTP Dad]

Welcome to AF!

Start with cleaning the EGR valve and the passageways to the plenum. Since it idles and runs rich when it is warm this may be bad and causing it to run rich. 2. Clean the idle air control valve and passageway on the throttle body. This will cause idle problems if the IAC isn't working correctly. 3. Check the map sensor since it can cause issues and finally you may want to replace the O2 sensor. It sends signals to the ecm to tell it how much gas to send into the engine. If it is bad this will cause poor fuel economy and a rich condition.

[hockeyguy]

Originally Posted by GTP Dad

Welcome to AF!

Start with cleaning the EGR valve and the passageways to the plenum. Since it idles and runs rich when it is warm this may be bad and causing it to run rich. 2. Clean the idle air control valve and passageway on the throttle body. This will cause idle problems if the IAC isn't working correctly. 3. Check the map sensor since it can cause issues and finally you may want to replace the O2 sensor. It sends signals to the ecm to tell it how much gas to send into the engine. If it is bad this will cause poor fuel economy and a rich condition.

It is running rich from start up. where is the map sensor??

[GTP Dad]

Look on the firewall. Should be held in place with two bolts have an electrical connector and a vacuum line connected to it.

[hockeyguy]

Originally Posted by GTP Dad

Look on the firewall. Should be held in place with two bolts have an electrical connector and a vacuum line connected to it.

I have 2 of those boxes mounted on a bracket. One of them has 1 hose and the other has 2 hoses could one of these be the canister purge valve??

I really appreciate your help.

[richtazz]

If you're talking about the bracket on the back of the intake, the one with one vacuum line is the MAP sensor, the other is the vapor canister purge solenoid. I agree with GTP that the problem is probably EGR related, but that valve is EXPENSIVE (about $175), so I don't blame you for exploring other avenues..

[hockeyguy]

Originally Posted by GTP Dad

Look on the firewall. Should be held in place with two bolts have an electrical connector and a vacuum line connected to it.

Ok I replaced the map and fixed the vacuum hose to the MAP but that line had fuel in it. I also have fuel in one of the 4 vacuum lines going to the throttle body coming from the fuel pressure regulator, this is a "T" line that goes to the MAP.
Could a bad fuel pressure regulator be cause my bad idle problem???

[maxwedge]

Certainly if you have fuel in the hose off the regulator it is leaking, this may or may not be the problem but fix it.

[hockeyguy]

Originally Posted by GTP Dad

Look on the firewall. Should be held in place with two bolts have an electrical connector and a vacuum line connected to it.

Ok I replaced the map and fixed the vacuum hose to the MAP but that line had fuel in it. I also have fuel in one of the 4 vacuum lines going to the throttle body coming from the fuel pressure regulator, this is a "T" line that goes to the MAP.
Could a bad fuel pressure regulator be cause my bad idle problem???

[GTP Dad]

Yes it could! Especially if you are sucking gas into the vacuum lines. The fuel pressure regulator regulates the amount of fuel pressure to the injectors if the pressure it too low it would cause the idle to be bad. You still should clean the IAC and passageways once you change the fpr.

[richtazz]

Get that FPR fixed soon. That is your problem and it will only get worse. If the raw fuel backs up the vacuum lines, it can damage other vacuum controlled devices, causing more problems and more headaches.

[hockeyguy]

Thanks guys for all the help.
My problem was the fuel pressure regulator.

Does anyone know how to get the steering colum cover off??
My low beams don't work and I have to pull the turn signal lever towards me to get them to blink.

Thanks again