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Cat Man
Cat Man, Caterpillar Engine Expert
Category: Heavy Equipment
Satisfied Customers: 8909
Experience:  23 Years Caterpillar Engine experience.
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1999 gmc: c1500 with Cat 3126 engine..Fast Idle..Cruse

Resolved Question:

I have a 1999 GMC C6500 with Cat 3126 engine. Fast Idle not operating. Cruse works perfectly. Have checked fast idle switch with meter and checks good. Any ideas? Previous owner said it just stopped working. Can i get a schematic of this system?  Does any other devices on this truck work in conjunction with the fast idle operation?
Submitted: 6 years ago.
Category: Heavy Equipment
Expert:  Cat Man replied 6 years ago.
Hi. Thanks for using JA! I will try and help you out.

Could you get me your engine serial number please? Thanks.
Customer: replied 6 years ago.
Engine Serial #7AS43130
Expert:  Cat Man replied 6 years ago.

Here is a fast Idle test for a 3126B Engine. << click here




Also, the fast idle parameter must be programed in order to work. You may need to have someone connect ET to the engine and make sure it is programmed.



Please let me know if you have any more questions.

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