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1998 Gmc Sierra Hard Cold Start Problem

blue-ss-camaro

By blue-ss-camaro
in Ask A GM Technician

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blue-ss-camaro Enthusiast

blue-ss-camaro

Posted
Posted

Like is in the title Its a 98 5.7 new cap rotor plugs wires . Has a cold start problem only when its about 40 and below. One day didnt start at all. When you turn the key on and try to start it and t doesnt start the fuel pump will run forever when you turn the key off. Today try to start it shut it off and the pump ran for like a minute and a half. Any ideas on what the problem is????

blue-ss-camaro Enthusiast

blue-ss-camaro

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Posted
Like is in the title Its a 98 5.7 new cap rotor plugs wires . Has a cold start problem only when its about 40 and below. One day didnt start at all. When you turn the key on and try to start it and t doesnt start the fuel pump will run forever when you turn the key off. Today try to start it shut it off and the pump ran for like a minute and a half. Any ideas on what the problem is????

 

 

ANYBODY???

PunchT37 Enthusiast

PunchT37

Posted
Posted

I would like to see a scan tool reading of the coolant sensor to see if it`s at least close to the ambient temp. before starting. Also, you might want to take it out to see if there`s gunk on the tip.

bobcat5544 Enthusiast

bobcat5544

Posted
Posted

Check your oil pressure sending unit located on the back of the engine just to the right of the distributor.

 

If your full pump stays running after you shut of your truck that is why. It is probaley leaking oil out of were the connector plugs in.

blue-ss-camaro Enthusiast

blue-ss-camaro

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Ok so I replaced the coolant sensor and I checked the fuel pressure. when I turned the key on it pressureized to 60 lbs and when I started the truck it was at a steady 52-53. Lets It sit for about 2 1/2 hours and it dropped to 50 I am woundering if it is suppose to drop???

bobcat5544 Enthusiast

bobcat5544

Posted
Posted

The fuel pressure drop is fine.

 

You stated the fuel pump will stay on at times after the truck is shut off correct?

 

If that is correct the only sensor that will keep the fuel pump running after it is shut off is the oil pressure sending unit

blue-ss-camaro Enthusiast

blue-ss-camaro

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yes i figured out that when it stays running is when I crank the engine for a long time nd it does not start thus creating oil pressure... cause the fuel pump to run when the truck does not run. Latly I have been turning the truck over once for about 3-5 sec. trying it again for about 6-8 sec then let the fuel pump run and on the third time it will start usaually. I am wondering what the pressure should be in the morning when I try to start it. I am certain I have a pressure leak just not sure where to start....

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