The car is an 85 GL 2wd A/T.

It devloped a problem recently where the engine revs up to 3000 RPMs+ whenever the A/T is shifted into "park". This happened very suddenly. I first noticed it after a trip when I tore thru some twisty, winding roads. Otherwise, (when under load), the timing/RPMS are normal, and the car performs very well.

I first suspected a vacuum leak, but couldn't find anything obvious . Now I'm thinking that it may be emissions, or one of the A/T-specific systems. The only mod I've done is to eliminate the AIR apparatus when I redid the exahaust system. The 85's have the AIR system piped into the cat, then back thru the intake. I've eliminated these before, and I can't imagine that this would cause the symptoms I've described.

I don't know A/T's very well, so there may be an obvious answer....

Any help or advice would be greatly appreciated,

thanks, John

my 88 spfi d/r dl. wagon does the same thing ,but only when it is colder out side , but since i do not have a tach ,i am not sure what the rpms would be , after i cleaned the maf it started to do this, but it does have 197,000mi on it

ummm.. random idea, and it may be a long shot...

 

have you checked ATF fluid? remember, check it with vehicle hot, running, in park... is it spfi? if so, find the FSM somewhere, or PM me asking me to email it. gimme your email address, and tell meif you can accept 2 attachments totalling less than 10 megabytes.

 

lots of troubleshooting info in there, but you may want to read it all through once, and maybe even twice, THEN go back and look for what your trouble is. if you understand how the whole system works (not hard to grok, but somewhat complex. lots of little steps and switches and sensors, thats all.) then you can understand why it tells you to do these things in this order... I cant think of what components might be causing your trouble right now, but the FSM can tell you.. im tired, thats all. PM and i can email, or if someone else has a link to download it? i didnt wanna bookmark the link and re post it, cuz it wasnt my site to funnel traffic to.

ummm.. random idea, and it may be a long shot...

 

have you checked ATF fluid? remember, check it with vehicle hot, running, in park... is it spfi? if so, find the FSM somewhere, or PM me asking me to email it. gimme your email address, and tell meif you can accept 2 attachments totalling less than 10 megabytes.

 

lots of troubleshooting info in there, but you may want to read it all through once, and maybe even twice, THEN go back and look for what your trouble is. if you understand how the whole system works (not hard to grok, but somewhat complex. lots of little steps and switches and sensors, thats all.) then you can understand why it tells you to do these things in this order... I cant think of what components might be causing your trouble right now, but the FSM can tell you.. im tired, thats all. PM and i can email, or if someone else has a link to download it? i didnt wanna bookmark the link and re post it, cuz it wasnt my site to funnel traffic to.

 

The A/T fluid is at the right level, and the tranny shifts fine. It's an 85 (carbed model), and I don't believe it's the fuel system since it runs well under load. Could not pull any error codes off the ECU.

I have the 85 FSM, and leafed thru there. Nothing jumped out at me. The emissions section has some troubleshooting info specific to trouble codes, but this doesn't help my situation. The wiring diagram has some A/T specific items that I'm not at all familiar with. Not even sure where those componenets are located. What section of the FSM are you referring to?

John

under the SPFI system, it gives you all the info on pulling codes from the ECU as well as laying out the function of each component, what it does to the ECU, etc. It also details how to test each component. I am guessing your idle air control solenoid is stuck open, or something like that.. i need to go to bed so my terminology is pretty bad, but theres a valve that lets extra air into the TB when the engine is cold. it closes when it gets warm. that valve, or the circuitry that actuates that valve (the ECUcoolant temp sensor, right guys?) could be at fault.

 

do you have an FSM? if you read that chapter you will know as much as I do. It seems boring i know but its not hard to get into, just dont rush and make sure you understand everything it says. if you have any issues "grokking" any of it, if it doesnt click in your head, go ahead and PM me and we can figure you out. if i can get some time before 4-6 am to sit by myself at my PC in the next day or two...

My car is a carberated model, so most of the SPFI stuff would not apply. Also, I could not pull any trouble codes, so it's a crap shoot as far as troubleshooting.

 

A temp sensor would make sense, except that it does not race when under load. It doesn't seem to be running like it's "warming up" when in gear (and in idle).

 

???

 

John

its just asking for a weekend at the draggs... or in a GL's case... at the tractor pulls!!!

john clean out your pm box :banana:

The car is an 85 GL 2wd A/T.

 

It devloped a problem recently where the engine revs up to 3000 RPMs+ whenever the A/T is shifted into "park". <snipped> thanks, John

 

This thread caught my eye. My Sube is an 88, 1.8L SPFI, D/R 5spd 4wd. 230,000 miles.

 

On HOT days (85F and above), after the motor gets fully warmed up, the idle speed will suddenly become very fast, anywhere from 2200 up to 2800 rpm. It will be ok one moment, then then the engine idle will suddenly JUMP up, like it's being commanded to do so by the ECM.

 

At this point, I'm suspecting either a vacuum leak somewhere that's being brought out by the heat, or maybe a sensor that's breaking down at hot. During this hi-rev idle thing the engine continues to run ok and the car can be driven, just allowing some extra time between shifts.

 

I'm planning to start checking and replacing all vacuum hoses and any sensors related to heat... any other ideas or suggestions? There IS one other piece of info that's involved, and on edit I wanted to add this in. My power steering pump has been seeping out p.s. fluid, which has made the top front of the motor stay kind of damp with a film of oil. I'm just wondering if maybe this power steering fluid which got on hoses and parts up around the top front of the motor, might have degraded them. Maybe I should fix the power steering pump thing and clean up the oil film before I start chasing this other problem?

 

Thanks,

James