Won't Stay Running

[kmcmillion]

My Fathers Truck - 2001 3500 - ~100K Miles

Truck was recently at the body shop for work - picked up truck, added fuel - drove apx. 50 miles or so - noticed low power, even shut off
Got the truck home and parked - wouldn't refire.

Changed fuel filter - water in filter at time of change
Still no start... Truck is losing prime. So far we have....
Rebuilt Fuel Filter Housing
Replaced Fuel Filter Housing
Drained Tank - Added New Fuel - Replaced Fuel Filter Again
Replaced Crappy Looking Fuel Lines To/From Fuel Filter Housing and Another Coming off the FICM
Replaced MPROP
Installed PPE Race Plug

In between each step we have tried to start the truck, we can get the truck to run as long as we preform "CPR" (pump primer) as soon as we stop, truck cuts out

Any ideas? We are driving ourselves nuts - tired of throwing parts at it.

 

[2004LB7]

Use clear tubing for fuel lines to watch for bubbles and trace down location

 

[TheBac]

Could be corrosion within the connectors of the main fuel line from the tank. You're probably going to have to try adding slight air pressure to the tank from the fill inlet to find the air leak.

 

[Bdsankey]

What work was done? Like @TheBac said, apply some air pressure to the tank cap. Use a rag and a blow gun, that usually works for me.

 

[kmcmillion]

What work was done? Like @TheBac said, apply some air pressure to the tank cap. Use a rag and a blow gun, that usually works for me.

Thank you!
@Bdsankey What work was done at the body shop? Or by us?

 

[Bdsankey]

By the body shop. I doubt they disconnected any fuel lines but I'm curious as it may help us point you in a direction.

 

[kmcmillion]

By the body shop. I doubt they disconnected any fuel lines but I'm curious as it may help us point you in a direction.

As far as I know, they shouldn't have. Both bed sides were replaced, fenders were repaired.
He was hit on the highway, driving in left lane - car merged right over into the truck

 

[Bdsankey]

Try pressurizing the tank slightly and see what happens or you can go directly to the below.


If that works (or you came straight to here), try this:
1) Disconnect the fuel supply to the engine (large fuel line on the driver side rear of the engine that is a 1/2" quick connect)
2) Run a piece of 1/2" hose off of the engine side fitting/tube into a bucket of clean fuel (hose clamp the end on the engine side)
3) Try priming the truck with the filter head mounted hand primer. If it primes, continue. If not, you've got an issue somewhere either on the suction or pressure side of the low pressure fuel system.
4) Let the truck run for say 10-15min at idle then shut the truck off.
5) Check the primer to see if it's hard. It will likely be slightly soft but should pump back up to rock hard easily.
6) Try restarting the truck.

If the above fixes your issue, then you have an issue on the low pressure supply side to the engine. This can be a collapsed line, plugged fitting, pinched line, air leak etc.

 

[kmcmillion]

Thanks so much! We'll try it out

 

[mojito5000]

I had a similar issue a few years ago. Did the tests above, rebuild my filter assembly, etc. At the time I had access to a tech2, and was able to diagnose the issue as low fuel pressure during cranking. Replaced the CP3 and have been golden since then.

 

[kmcmillion]

I had a similar issue a few years ago. Did the tests above, rebuild my filter assembly, etc. At the time I had access to a tech2, and was able to diagnose the issue as low fuel pressure during cranking. Replaced the CP3 and have been golden since then.

I keep getting a feeling it is the CP3, but cranking we had desired fuel pressure. I am just using my Edge Insight for readings though

 

[2004LB7]

Put a clear hone going into the CP3. If the fuel is clear then do a return rate test on the pump and injectors. If bubbles then find and fix the source and check again

 

[Bdsankey]

I keep getting a feeling it is the CP3, but cranking we had desired fuel pressure. I am just using my Edge Insight for readings though

You will always have desired fuel pressure, that's what the ECM is commanding. Actual is what you likely didn't have.

If your actual matched desired and the truck did not start you have another issue that is stopping the ECM from firing off the injectors.

In your case, I'm betting actual did not match desired and thus you have a fuel issue based on the truck running while pumping the primer bulb. My post above will help you determine if the issue is the truck side or engine side.

 

[kmcmillion]

I had a friend from work bring his scanner, he was able to confirm that the actual and desired are matching which is what my insight showed.

We did run clear line to the FICM to check for bubbles, that did not indicate we were sucking air anywhere.

We also disconnected the fuel supply and ran fuel from a jug, primed, would only start for short amount of time without continuously pressing the primer.