Really high idle at start

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07-10-2011 | 12:05 PM

Dholtham

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Joined: Jul 2011

Posts: 12

Really high idle at start

I have a 1990 chevy k3500 with the 7.4L.. When i start the truck it idles very high for about 3 minutes and then it kicks down to around a normal idle, Anyone have ideas on why this is? I just bought the truck.

07-10-2011 | 03:35 PM

Wiked

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Joined: Jun 2011

Posts: 368

From: Pennsylvania

maybe its just trying to warm up or its a throttle position sensor (TPS)

07-10-2011 | 04:52 PM

MrDragon

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Joined: Jul 2011

Posts: 304

From: Indianapolis

Is that a TBI motor ? I'm not sure if they still use an electric choke or not but it might be as simple as that and it just takes a minute to get up to operating temp.

07-10-2011 | 07:16 PM

Wiked

Senior Member

Joined: Jun 2011

Posts: 368

From: Pennsylvania

goddamn your right dragon....

i keep forgetting that older motors dont use the newer sensors and stuff

07-10-2011 | 09:32 PM

Dholtham

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Posts: 12

Actually it is staying at quite a higher idle the entire time i have it on

07-11-2011 | 12:20 PM

MrDragon

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Joined: Jul 2011

Posts: 304

From: Indianapolis

Could be a simple adjutment of the throttle or it's even possible the timing was bumped forward a bit. They may not fix the problem but are easy to check and adjust.

07-11-2011 | 12:54 PM

HahaJK

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Joined: Jul 2011

Posts: 4

Quote:

Originally Posted by Dholtham

I have a 1990 chevy k3500 with the 7.4L.. When i start the truck it idles very high for about 3 Car Accessories minutes and then it kicks down to around a normal idle, Anyone have ideas on why this is? I just bought the truck.

Your tps seems to be too high. Either that or your truck just wants to warm up as fast as possible.