Hi Revs at cold idle, is this normal.......

[rugbydelboy]

I have 2004 trailblazer and have just come over from the other site as I was lead here by another memember and have found GMTN to be awesome. I have a question and am not sure how to post something so I am sending you this message. When I start my Trailblzer from cold or even when it is warm the car starts and immediatly goes up to aboyt 1500rpm, I can here a fan running, I think this is something to do with the emmisions but am not sure. After about 5-10 seconds the fan ramps down and the revs drop to about 900, then when up to temperature the idle is around 6-700, are these speeds normal and any ideas as to why the idle would be so high on start up??

Keep up the good work, the site is awesome

Delboy, Ontario, Canada

 

[blazinlow89]

Mine does pretty much the same thing, even sometimes when it is 80* outside it will run with high idle for 10-20 seconds, then drop to between 600 and 800, the after driving idle is right above 600.

 

[Sparky]

Startup idle like that is normal, mine does the same also. I typically wait the 10 seconds for the engine speed to drop below 1000 before putting it in gear.

 

[hockeyman]

First, do you have any codes stored into your system? I'd have it scanned first to see if there are any internal issues.

What I did for a friends '02 trailblazer:
His started to idle around 2k and would stay there for a relatively long time...even once the engine was warm. I followed these procedures (6th video down) and cleaned the throttle body, along with resetting the PCM. I removed the PCM fuses once I started to take the throttle body assembly apart, and put them back in once I was finished cleaning it, which was about 45 minutes later.

After all was re-installed, I started it and the idle went back up to around 2k during the first start-up, then slowly backed down until the PCM had a chance to re-learn everything (with a very clean throttle body). He took it for a ride and returned 1/2 hour later. Shut it down and re-stared, and the idle has been perfect ever since.

During a cold start-up, the idle now goes to about 1,500k for a few seconds, then drops down to around 800 and stays there. Since I already had a few cans of Throttle Body Cleaner in my garage, it was a 100% free fix...at least, for him

 

[rugbydelboy]

First, do you have any codes stored into your system? I'd have it scanned first to see if there are any internal issues.

What I did for a friends '02 trailblazer:
His started to idle around 2k and would stay there for a relatively long time...even once the engine was warm. I followed these procedures (6th video down) and cleaned the throttle body, along with resetting the PCM. I removed the PCM fuses once I started to take the throttle body assembly apart, and put them back in once I was finished cleaning it, which was about 45 minutes later.

After all was re-installed, I started it and the idle went back up to around 2k during the first start-up, then slowly backed down until the PCM had a chance to re-learn everything (with a very clean throttle body). He took it for a ride and returned 1/2 hour later. Shut it down and re-stared, and the idle has been perfect ever since.

During a cold start-up, the idle now goes to about 1,500k for a few seconds, then drops down to around 800 and stays there. Since I already had a few cans of Throttle Body Cleaner in my garage, it was a 100% free fix...at least, for him

Thanks I will check all of these helpful hints and hopefully cure my problem

 

[GMDUDE2003]

Both my 2003 Envoy and the Saab both do it. Nothing to worry about really.

 

[fadyasha]

Same here 2003 tb

 

[NewfieEnvoy]

Same here, 07 Envoy