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Help with a diagnosis?


3pt1lumina

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Put the 90 back on the road today and seems to be running pretty well. The high idle issue is officially resolved. I have a quick question about a couple of things though:

 

When I leave a stop light gentle, I have a hesitation that's pretty noticeable. It doesn't feel like the car is going to die, just hesitates and then goes. Some other 3.1 MPFI motors like mine do this too when I have driven them. I'm assuming that is normal for these?

 

Also, at a red light, it will idle at 1k. If I take my foot off the brake and inch forward, the idle fluctuates ~ 300rpms and the car starts to shake. What the hell is this?

 

And last, the car seems to "chug" in park/neutral. It sounds as if it's misfiring but it's definitely not. I was told that because of the exhaust leak in the downpipe before the catalytic that this could be the cause. I am going to patch that temporarily to see if it solves the problem. If it does, I'll put Z34 exhaust on the car :biggrin:

 

If anyone has any ideas/suggestions please feel free to throw them out. I'm curious to see what you guys think.

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When I leave a stop light gentle, I have a hesitation that's pretty noticeable. It doesn't feel like the car is going to die, just hesitates and then goes. Some other 3.1 MPFI motors like mine do this too when I have driven them. I'm assuming that is normal for these?

 

neither of the 3.1MPFI w-bodies that I have owned have ever done that :dunno:

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Fuel filter is ~ 2 years old which is only about 6k. Today driving to school I got an SES code 32. If not this week, next week I'll have one of the techs look at it and see what they think. This car has thrown this code since 1999 and it only happens over 50mph. Thing is, the car will "stumble" then the SES will go on. Wierd I know.

 

But, yay for OBD1 because I coded it with my handy dandy paperclip I keep in the center console when I got to school. hahaha

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Fuel filter is ~ 2 years old which is only about 6k. Today driving to school I got an SES code 32. If not this week, next week I'll have one of the techs look at it and see what they think. This car has thrown this code since 1999 and it only happens over 50mph. Thing is, the car will "stumble" then the SES will go on. Wierd I know.

 

But, yay for OBD1 because I coded it with my handy dandy paperclip I keep in the center console when I got to school. hahaha

 

CODE 32

 

Trouble Code 32 indicates that the Exhaust Gas Recirculation (EGR) system has detected a fault. There are two types, the older integrated electronic EGR contains a voltage regulator which converts the ECM signal to provide different amounts of EGR flow by regulating the current to the solenoid. The ECM controls EGR flow with a pulse width modulated signal (turns "ON" and "OFF" many times a second) based on airflow, TPS, and RPM. This system also contains a pintle position sensor which works similar to a TPS sensor, and as EGR flow is increased, the sensor output also increases. The other type is a digital 3-level EGR used in newer engines. Code 32 will get set when:

 

* (Integrated EGR) Coolant temperature above the specified amount, EGR should be on.

* (Integrated EGR) EGR pintle position does not match duty cycle.

* (Digital EGR) Failure of EGR system.

 

Possible causes include:

 

1. Faulty EGR valve-to-ECM connection

2. Plugged EGR passages and/or sticking EGR valve

3. Defective EGR valve

4. Defective ECM

 

Check the shop manual for details on vehicle specific EGR valve applications.

 

That's the code 32 definition, wasn't sure if you had gotten it or not, but just for posterity here it is in this thread.

 

Your little stumble could possibly be related, have you ever cleaned the EGR passages?

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Fuel filter is ~ 2 years old which is only about 6k. Today driving to school I got an SES code 32. If not this week, next week I'll have one of the techs look at it and see what they think. This car has thrown this code since 1999 and it only happens over 50mph. Thing is, the car will "stumble" then the SES will go on. Wierd I know.

 

But, yay for OBD1 because I coded it with my handy dandy paperclip I keep in the center console when I got to school. hahaha

 

CODE 32

 

Trouble Code 32 indicates that the Exhaust Gas Recirculation (EGR) system has detected a fault. There are two types, the older integrated electronic EGR contains a voltage regulator which converts the ECM signal to provide different amounts of EGR flow by regulating the current to the solenoid. The ECM controls EGR flow with a pulse width modulated signal (turns "ON" and "OFF" many times a second) based on airflow, TPS, and RPM. This system also contains a pintle position sensor which works similar to a TPS sensor, and as EGR flow is increased, the sensor output also increases. The other type is a digital 3-level EGR used in newer engines. Code 32 will get set when:

 

* (Integrated EGR) Coolant temperature above the specified amount, EGR should be on.

* (Integrated EGR) EGR pintle position does not match duty cycle.

* (Digital EGR) Failure of EGR system.

 

Possible causes include:

 

1. Faulty EGR valve-to-ECM connection

2. Plugged EGR passages and/or sticking EGR valve

3. Defective EGR valve

4. Defective ECM

 

Check the shop manual for details on vehicle specific EGR valve applications.

 

That's the code 32 definition, wasn't sure if you had gotten it or not, but just for posterity here it is in this thread.

 

Your little stumble could possibly be related, have you ever cleaned the EGR passages?

 

Thanks for putting that in here. I was looking for that. The EGR was replaced... May 2003 IIRC. It could very well be clogged again but even after it was replaced, the light came on still. I'm guessing there is a vacuum leak. Probably a line or something that I've been overlooking for so long.

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That happened to me, replaced the EGR and the SES ligth still came one. Then I got thr bright idea to clean the port ( which wouldnt ya know it was clogged with carbon )

 

So that very well may be your problem, just being clogged up.

 

But about your vaccum leak, does it drive bad or "stumple" all the time, or just once n a while?

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That happened to me, replaced the EGR and the SES ligth still came one. Then I got thr bright idea to clean the port ( which wouldnt ya know it was clogged with carbon )

 

So that very well may be your problem, just being clogged up.

 

But about your vaccum leak, does it drive bad or "stumple" all the time, or just once n a while?

 

At idle it's almost all the time. Driving it only stumbles over 50mph... and even that it's hardly noticeable.

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Its the EGR. Same thing happened to me when I replaced/cleaned the EGR. So the EGR is bad or the port just needs to be cleaned.

 

If it doesnt do it all the time, dw you dont have a vaccum leak. If you did, the only time it would run good would be at WOT...

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