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89 Eldorado with high RPMs! help!


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nakmario
Anonymous Poster
nakmario@gmail.com

Nov 9, 2008, 7:38 PM

Post #1 of 2 (1358 views)
89 Eldorado with high RPMs! help! Sign In

Hello,
Ive recently purchased an '89 Eldorado with a 4.5L engine. I bought it on the cheap since it had blown head gaskets. Those were replaced about a month ago by a professional.

I drove the car for about 100 miles and now I have a new problem.

When I start the car, it idles at the normal range. However, after it warms up it continues to increase the RPMs on the engine. In Park it will idle at 2000 RPMs.

This is particularly scary when driving since it makes braking more difficult since the car operates as though I have the foot on the gas at all times. I've stopped driving it for safety reasons and was hoping that you might be able to help me diagnose the problem so that I can maybe fix it myself. I dont really have the money to take it to the nearest mechanic pay for them to fix it - especially since I suspect that my last mechanic is at fault for this.

I've read online that similar people have Vacuum Leaks, causing similar problems. I've also read that it could be the Idle Speed Actuator that has failed.

Im not conviced it is the Vacuum Leak because the High RPMs increase steadily and maintain a high and steady rate. Also... the idle speed is different when in Drive and in Park so maybe it's the transmission?

One interesting thing that got me hoping it was an electrical problem was that when I turn on the A/C the RPMS instantly drop to, and stay at, around 1800 RPMs.

Do you believe that it is the transmission, the Idle Speed Actuator, a Vacuum Leak or even a dirty Throttle Body?

Please help! I'm broke and I dont know much about cars!
This is my first car and it's really heartbreaking to have it break after 100 miles.

Thank you for any advice, in advance.

Mario

PS
It is an 89 Eldorado, 4.5L with 101k miles on it. There are no check engine lights or messages that show up and the engine has no problem starting up or shifting gears while driving.


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Nov 9, 2008, 8:55 PM

Post #2 of 2 (1356 views)
Re: 89 Eldorado with high RPMs! help! Sign In

Just a thought on this: A lot got messed with to do the head gaskets and items unplugged - check all the ones that would be touched for that job.

I have had troubles with the idle speed actuator motors on that engine - thinking back - I think they wouldn't hold idle high enough. If you unplug it will it idle differently at all? Would be a clue anyway. As I recall they weren't cheap so check if it moves at all.

Not surprised that A/C or putting in gear makes idle drop some as they are "loads" on the engine,

T







 
 
 






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