Truck not starting cold

sponhower

sponhower

New member
Has anyone else had this problem after having a rebuild that the truck when cold cranks for about 15-20 seconds before starting. I was told it could be the oil pump doesn't have some kind of check valve in it causing it not to hold pressure like a stock pump does. Does that make sense? Any suggestions would be great. I'm trying to sell the truck and it would be great to either fix the problem or at least have a real reason for it to tell someone. Thanks again.
 
The Bronze

The Bronze

New member
Sounds like fuel pressure. With such a long crank time, it is more likely that the fuel system is draining back through the pump check valve at shut down. You can verify this without tools be just bumping the ignition to start (from the off position) a good 5-10 times. You should hear the fuel pump hum each time for a few seconds. Then try to start normally. If it fires right up, your long crank is due to the length of time it is taking the pump to refill the fuel system.

No fuel pump noise while bumping the key? That's easy enough to run down as well. Of course, it sure wouldn't hurt to have a fuel gauge attached to make sure it is even a fuel problem.
 
sponhower

sponhower

New member
Re: Truck not starting cold

The fuel pump doesn't even kick on at first when cold. When warm it will and as soon as I'm cranking and the gauge starts to register oil pressure the fuel pump kicks on
 
DaveP

DaveP

Active member
Re: Truck not starting cold

sponhower said:
The fuel pump doesn't even kick on at first when cold. When warm it will and as soon as I'm cranking and the gauge starts to register oil pressure the fuel pump kicks on
Click to expand...

There ya have it.

Replace the fuel pump relay. The long crank when cold is because the oil is thick and takes much longer to build enough pressure to engage the oil pressure switch. When hot, pressure rises much more quickly.

If you still have issues after the relay is changed, pay attention to Kelly's (The Bronze) post above regarding bleeding-off of fuel pressure, and how to identify this malady.

If you don't hear the pump run for 2-3 seconds when you turn the key on, replace the relay.
 
Throws

Throws

Active member
Re: Truck not starting cold

DaveP said:
There ya have it.

Replace the fuel pump relay. The long crank when cold is because the oil is thick and takes much longer to build enough pressure to engage the oil pressure switch. When hot, pressure rises much more quickly.

If you still have issues after the relay is changed, pay attention to Kelly's (The Bronze) post above regarding bleeding-off of fuel pressure, and how to identify this malady.

If you don't hear the pump run for 2-3 seconds when you turn the key on, replace the relay.
Click to expand...

This is why I have a fuel pressure gauge. ;) Actually came in handy one morning when the truck wouldn't start and the gauge showed zero. Bad relay. Spare was swapped in and it fired right up.

Good advice on the relay. 20yrs old... they're going to fail at some point.

-P
 
sponhower

sponhower

New member
Re: Truck not starting cold

Changed relay and it starts cold. But it was running so rich it was choking it out.
 
HopnDude

HopnDude

I B Derpin.
Re: Truck not starting cold

sponhower said:
Changed relay and it starts cold. But it was running so rich it was choking it out.
Click to expand...

Disconnect battery. Flip ignition switch 2/3 times to ensure all juice is drained from all capacitors in computer. Reconnect battery. Let ECM/PCM remap it'self. Enjoy!
 
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