Really high idle at start

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Jul 10, 2011 | 11:05 AM

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.

Jul 10, 2011 | 02:35 PM

Wiked

Senior Member

Joined: Jun 2011

Posts: 368

From: Pennsylvania

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

Jul 10, 2011 | 03:52 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.

Jul 10, 2011 | 06:16 PM

Wiked

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Joined: Jun 2011

Posts: 368

From: Pennsylvania

goddamn your right dragon....

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

Jul 10, 2011 | 08:32 PM

Dholtham

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Posts: 12

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

Jul 11, 2011 | 11:20 AM

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.

Jul 11, 2011 | 11:54 AM

HahaJK

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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.