05 express 3500 intermittently doesn’t start

[jh987654]

I have a 2005 express 3500 with 100k miles and v-8.

The van will not start and there is no pattern. I turn the key and i get electric to everything in the dash. I turn the key to start and I get nothing. After 5-6 minutes the car just starts. It will work for days and then do this again. I have replaced the battery and 2 days later it occur again.

Where do I start looking?

[MT-2500]

Originally Posted by jh987654

I have a 2005 express 3500 with 100k miles and v-8.

The van will not start and there is no pattern. I turn the key and i get electric to everything in the dash. I turn the key to start and I get nothing. After 5-6 minutes the car just starts. It will work for days and then do this again. I have replaced the battery and 2 days later it occur again.

Where do I start looking?

When no start check for lose of spark and fuel pressure.

At 100k it is time for a good AC delco tune up.

Any check engine lights or codes?
When no start can you hear fuel 2 second pump prime up key on?

The only true test on a fuel pump is to check the direct fuel pressure from fuel pump.
A quick test is to block off the return line and see if fuel pressure comes up to 75-85 lbs.
But do not run the pump at full pressure very long.
Also when testing fuel pump and pressure you need to tape a gauge to outside windshield or outside mirror and drive it on the road for 20 -30 minutes
until the pump gets has run a while to check for a pump fading out after hot.

Hard to start cold or hot and fuel pressure testing guide lines.
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.
If pump has full pressure with return line blocked and low pressure without it blocked most usually the fuel pressure regulator is leaking or not holding pressure.
Later V6 and V8 gm engines should have 60-66 fuel pressure.
Cold start should be 64-65 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 60-66 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 in system.
Post back fuel pressure readings.