2000 Suburban 93Kmiles 5,3L : weird start.
Christophe Salvain
08-29-2007, 07:38 AM
Hi
Cold engine : when I turn the key to start first the engine doesnt start (no idle and stall). But just after, at the second time, it starts fine at idle (without pushing the accelerator pedal all the way to the floor).
Hot engine or daily use : it starts at any time.
Any advice is welcome
Christophe Salvaing
Cold engine : when I turn the key to start first the engine doesnt start (no idle and stall). But just after, at the second time, it starts fine at idle (without pushing the accelerator pedal all the way to the floor).
Hot engine or daily use : it starts at any time.
Any advice is welcome
Christophe Salvaing
taillight
08-29-2007, 08:17 AM
Check fuel pump pressure before turning to start. It should be 60 pounds. I am not sure what that is in metric but I can find out.
Christophe Salvain
08-30-2007, 03:03 PM
Check fuel pump pressure before turning to start. It should be 60 pounds. I am not sure what that is in metric but I can find out.
Fuel pump pressure tested today 62 pounds (4,34 h/pa)
Any other ideas :) ?
Christophe
Fuel pump pressure tested today 62 pounds (4,34 h/pa)
Any other ideas :) ?
Christophe
taillight
08-31-2007, 07:53 AM
Is it at 60# when you try to start it the first time ?
Christophe Salvain
08-31-2007, 08:40 AM
Is it at 60# when you try to start it the first time ?
Dont know ... :banghead:
I'll bring back the Sub to my mechanic in order to test at the real first time.
Thank you.
Christophe
Dont know ... :banghead:
I'll bring back the Sub to my mechanic in order to test at the real first time.
Thank you.
Christophe
MT-2500
08-31-2007, 09:20 AM
You have to have full fuel pressure for the injectors to start on a cold start.
Also on the 5.3 check the fuel pressure regulator for corrct pressure and for gas in the vacuum line.
Specs on it is 55/62 lbs of pressure
Here is some guide lines of fuel pressure checking.
Hard to start cold.
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.
Also on the 5.3 check the fuel pressure regulator for corrct pressure and for gas in the vacuum line.
Specs on it is 55/62 lbs of pressure
Here is some guide lines of fuel pressure checking.
Hard to start cold.
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.
Automotive Network, Inc., Copyright ©2025