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Old 04-01-2006, 08:38 PM   #1
95 Prix SE
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Car idles at 2000 RPM

Here is the issue that brings me to these forums: mechanically, I am a noob. Every time I pick up a wrench, I end up calling a tow. Well, maybe not that bad, but you get the pic.

I have a 95 Pontiac Grand Prix SE, 6 cyl. Recently, when I start the car, the idle starts off a little low, then jumps up to about 1500-2000 rpm.

Not too long ago, I had a new water pump put in, but I can't see what that has to do with anything. I also had a new hose / line put in that goes from the pcv to behind the engine, to where there is some kind of core. Midas did it for me. In years past, I have also had cooling system problems. I've had a new fan, radiator put in, and another time I had to have a new intake manifold installed. These days, I have to keep putting in new coolant, but there are no puddles under the car and a pressure test yields no results. That to me suggests that the coolant is getting into either the head gasket or back into the previously replaced intake manifold.

How much of this might be related to the speeding idle? Any suggestions about the idle?

Chris
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Old 04-01-2006, 08:57 PM   #2
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*nevermind this*

Last edited by shadowedII : 04-01-2006 at 11:04 PM.
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Old 04-01-2006, 10:36 PM   #3
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Quote:
Originally Posted by 95 Prix SE
Here is the issue that brings me to these forums: mechanically, I am a noob. Every time I pick up a wrench, I end up calling a tow. Well, maybe not that bad, but you get the pic.

I have a 95 Pontiac Grand Prix SE, 6 cyl. Recently, when I start the car, the idle starts off a little low, then jumps up to about 1500-2000 rpm.

Not too long ago, I had a new water pump put in, but I can't see what that has to do with anything. I also had a new hose / line put in that goes from the pcv to behind the engine, to where there is some kind of core. Midas did it for me. In years past, I have also had cooling system problems. I've had a new fan, radiator put in, and another time I had to have a new intake manifold installed. These days, I have to keep putting in new coolant, but there are no puddles under the car and a pressure test yields no results. That to me suggests that the coolant is getting into either the head gasket or back into the previously replaced intake manifold.

How much of this might be related to the speeding idle? Any suggestions about the idle?

Chris
The first thing that would help would be for you to supply us with any DTC's that may be present. Then think vacuum leak. The PCM on your vehicle controls timing, fuel delivery and idle speed. What it can't cope with is a vacuum leak. The first place I would look would be in the vicinity of where Midas just did their work because someone just had their hands in there and because that's as good a place to start as any. Whatever you do, completely ignore this advice;

Quote:
Originally Posted by shadowedII
Check out your thermostat. SOunds like it's just feeding to much fuel to the engine because it isn't reading the engine temperature right.
Thermostats don't feed fuel, thermostats don't read engine temperature, excessive fuel delivery does not increase idle speed. I think that might be a worlds record for amount of BS ever spewed in two sentences.
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Thanks for the pic, jedimario.

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Old 04-01-2006, 11:03 PM   #4
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Quote:
Originally Posted by vwhobo
Thermostats don't feed fuel, thermostats don't read engine temperature, excessive fuel delivery does not increase idle speed. I think that might be a worlds record for amount of BS ever spewed in two sentences.

One thousand pardons! I'm only feeding back what I got from my mechanic when my idle was running too high. But in the end my idle was fixed and my engine ran great.

(is it the thermostat that controls the coolant in order to regulate the engine temperature?)
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Old 04-02-2006, 12:15 AM   #5
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Quote:
Originally Posted by shadowedII
One thousand pardons! I'm only feeding back what I got from my mechanic when my idle was running too high. But in the end my idle was fixed and my engine ran great.

(is it the thermostat that controls the coolant in order to regulate the engine temperature?)
The answer to your question is, the thermostat regulates the minimum coolant temperature. So more or less, yes.
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Thanks for the pic, jedimario.

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Old 04-02-2006, 06:10 AM   #6
95 Prix SE
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Quote:
Originally Posted by vwhobo
The first thing that would help would be for you to supply us with any DTC's that may be present. Then think vacuum leak. The PCM on your vehicle controls timing, fuel delivery and idle speed. What it can't cope with is a vacuum leak. The first place I would look would be in the vicinity of where Midas just did their work because someone just had their hands in there and because that's as good a place to start as any.

First, thanks a load. I really appreciate it.

Hmmm.... well you know... now that you mention it, it was indeed a vacuum line that Midas installed.

A couple of things tho: DTC's? PCM? Shame on me... but those are new to me.

PCM... that's the same at the PCV isn't it?

Chris
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Old 04-02-2006, 07:14 AM   #7
97Talonchik
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PCM= Powertrain control module, your computer in your car...these are also ECU (electronic control unit) or ECM (engine control module)

DTC= Diagnostic trouble code
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Old 04-02-2006, 09:22 AM   #8
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Quote:
Originally Posted by vwhobo
The answer to your question is, the thermostat regulates the minimum coolant temperature. So more or less, yes.

Thank you for enlightening me.
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Old 04-02-2006, 04:16 PM   #9
95 Prix SE
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Quote:
Originally Posted by 97Talonchik
PCM= Powertrain control module, your computer in your car...these are also ECU (electronic control unit) or ECM (engine control module)

DTC= Diagnostic trouble code

O.k., well my "Check Engine Light" hasn't come on, and based upon past experience no hundred-plus dollar diagnostic could yield any results from the computer unless the light first came on. WHen I had that vacuum line replaced, the most they could get me was some "soft codes" that didn't really tell them (Midas) any thing.

So as of right now, I can not provide any of that information because I haven't taken the car in yet.

But thanks for the info.

Chris
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