ColoradoSilverado

My truck always started at the first turn of the key, now since last week I have to turn the key like three or four times to start. I suspect a fuel delivery problem because it seems to start a little easier if I play with the throttle. Fuel pump and filter were replaced about 8 months ago, the truck has 186,000 miles on it. Can you guys give me some advice on where and how to start troubleshooting ?

Thanks,
Bert

__________________
2000 Silverado,, Z71
5.3 Ext. Cab, Long Bed
As of Oct. 2009, 192,000 miles.

MT-2500

Any check engine lights or codes?
Was the reolacemnent fuel pump a aftermarket or Airtex?
Have you checke the fuel filter or fuel pressure?

The 5.3 has a lot of fuel pressure regulator problems.
Pull vac. hose off and look for fuel in vacuumn line.
If so replace pressure regulator.
Also.
Run a full fuel pressure check.
Hard to start cold or hot?
Check cold start fuel pressure.
Check engine running fuel pressure.
Check engine running on the road fuel pressure.
Then shut it off and watch for fast leak down.
Pinch off at rubber part or block off return line and check full pressure.
Later V6 and V8 gm engines should have 55-66 fuel pressure.
Cold start should be 55/62 lbs of pressure.
If you do not have full fuel pressure on a cold start the injectors will not squirt fuel.
Do not leave home without it.
Engine running should be 55/62 lbs pressure depending on engine load.
Full pressure with return pinched off should be 75-85 or more.
And if it has a fast leak down after shut off you have a leak.
If pressure does not come up with return line pinched or blocked off.
Go to fuel filter and hook a gauge direct to a line at fuel filter.
Pressure should come up to 75 or more and will hold after fuel pump is turned off.
If it leaks down there after fuel pump is turned off it is LEAKING BACK THREW PUMP CHECK VALVE OR PUMP MODULE LINES.
Post back your fuel pressure readings.
MT

__________________
Remember proper testing gives us the answer to many problems.
MT

j cAT

some time in 2007 you replaced the fuel pump....? at that time what pump did you use ? did you replace the fuel pump relay ?

If you used an aftermarket fuel pump this is what usually occurs..

ColoradoSilverado

The fuel pump I used came from NAPA including the fuel filter.

Bert

__________________
2000 Silverado,, Z71
5.3 Ext. Cab, Long Bed
As of Oct. 2009, 192,000 miles.

MT-2500

Napa is the parts store brand.
What brand of fuel pump was on the fuel pump box?

__________________
Remember proper testing gives us the answer to many problems.
MT

ColoradoSilverado

I will get a fuel pressure tester this weekend and do some test.

Bert

__________________
2000 Silverado,, Z71
5.3 Ext. Cab, Long Bed
As of Oct. 2009, 192,000 miles.

MT-2500

Airtex fuel pump?
Also check for fuel in vacuumn line on fuel pressure regulator.

__________________
Remember proper testing gives us the answer to many problems.
MT

chevy393

im not 100% sure on what the problem could be but i replaced my fuel pump in my 2000 silverado 1500 ext cab 4x4 5.3L about 5 months ago with a fuel pump from pep boys that cost about $240-$270 ish cant remember exactly and i dont know the brand so why i said all that and i havnt had a hard starting probelm at all, put the new one in and boom started right up np from day one of new pump, just felt i should throw that out there to say i didnt have a problem with mine BUT im not sayin ur arnt ether though : \

j cAT

you must start a new posting with your issues,,,,,,

this is for another forum member...

ColoradoSilverado

Where do you guys get those fuel pressure testers ? I went to my local Autozone, Checkers and Advance and nobody loans out one of those.
They'll sell me one for $40.

Bert

__________________
2000 Silverado,, Z71
5.3 Ext. Cab, Long Bed
As of Oct. 2009, 192,000 miles.

MT-2500

Tool dealers like snap on and mac/matco sell them off of there trucks.
or the auto parts places sell them.

Best one to get is one with a long hose to reach windshield or rear view mirrow for testing on the road.
Also extra fittings for checking ford and other brands of auto/trucks.

Also a old R-12 AC gauge set can be used on GM scrader valve fuel test fitting.
But gas is a little hard on AC hoses valves.

__________________
Remember proper testing gives us the answer to many problems.
MT

chevy393

i was just sayin that i use and aftermarket fuel pump and i dont have hard starting problems, as one of the other guys said "if u put in an after market one sometimes u have hard starting problems" and was just saying that i used one form pep boys and i dont have hard starting problems but i also said it still might be it idk, was just lettin him know that i didnt have a problem with my aftermarket fuel pump

ColoradoSilverado

Okay, finally got a fuel pressure tester. Here are some readings: Ignition on = 56 PSI, Engine idling = 50 PSI, no fuel in vacuum hose on fuel pressure regulator. But when I turn off the ignition the fuel pressure drops down to zero within 10 seconds. What could this be ? Checked the resistance on all injectors, they're all around 12.6 - 12.8 Ohms. I checked all fuel lines and don't see a leak anywhere. When driving it runs just fine, no loss of power or anything.

Bert

__________________
2000 Silverado,, Z71
5.3 Ext. Cab, Long Bed
As of Oct. 2009, 192,000 miles.

MT-2500

From what you have there pressure is low and leaking off fast,

But
We Need the full fuel pressure check.
Post back all reradings as outlines in the fuel pump/pressure check.

__________________
Remember proper testing gives us the answer to many problems.
MT

j cAT

the fuel pump is defective should ,,hold pressure...get delphi pump unless you want to do this after a year goes by..

napa has various pumps,,not sure what you got..but delphi has proven to be the forum choice...

good luck..