Van cranks but no start already replaced ecu

Hello,

I have a 97 2500 express van. The other day the van suddenly would not start. It would crank but would not fire. So i had a mechanic look at it, no fuel or no spark. He told me that most likely the ecu was bad. So he took the ecu out and replaced some stuff in the ecu and brought it back. PLugged it in and she fired right up. One day later I was working and my van is doing the same thing. It will crank but not start. Any ideas??? Thanks

Ignition module or pickup coil maybe.

Welcome to AF,
What mileage and engine and tune up history?
Check for lose of fuel pressure or spark to all plugs when no start.
Any stored codes?

it has 200k. Regular tune up done. Already checked furl and spark plugs. SOmething is making my ecu get fried...

Any codes?
What is the fuel pressure reading?
Double check good hot blue spart to all plugs.
The VCM very seldom goes bad.
Get it on a good engine capable scanner and see what all of the VCM readings and codes are.

Here is an update. I went back to the van this morning and it started. So I drove it home. So it seems like its doing it when I have been driving around for a while. Mechanic thinks maybe cps.. I am going to let the van run for awhile in my drive way to duplicated the problem.

Yes you have to catch it when it is doing it.
I always tape a fuel pressure gauge to windshield and watch fuel pressure when it does it.
Does you mechanic have a good engine capable scanner to check it?
A lab scope is a good tool to check crank sensor out.
Let us know how it goes.
Good Luck

he does not have a scanner.

Some parts places give free scan/codes checks.
Good luck

can i get the scan doen even if my car is running to see if anythng is wrong? I am not even getting a check engine light.

Update, the van is not starting again. It started this morning and went to home depot. When i came out of home depot it wouldn't start.... This is really making me mad

Update, the van is not starting again. It started this morning and went to home depot. When i came out of home depot it wouldn't start.... This is really making me mad


Before you lose your cool.
Do some testing when it no start.
Does the engine crank good?
Can you hear fuel pump run ley on prime up?
Check for lose of fuel pressure and for good spark to all plugs.
Get the codes checked when it is running.

just replaced the fuel pump and everything is in order. We will see how long it lasts. Thanks everyone

just replaced the fuel pump and everything is in order. We will see how long it lasts. Thanks everyone

You are welcome.
How did you find the problem?