Engine cranks and has fuel pressure but no start

[spacecadet]

Went to drive off on a trip on Friday, engine cranked, fuel pressure at filter, dash display normal but no start. Tried 3 times for about 2 seconds each. Verified fuses and then queried codes - none thrown. Went back out and truck started right up, and did so every time on the 3 day trip. Nothing like a little drama to start a road trip.

Truck gets driven regularly and hasn't had any engine issues at all in 150,000 miles. I've searched TDR posts on "no start" but haven't found exactly this situation. Looking through the service manual, it seems that a faulty ASD relay could cause this situation, but wouldn't that throw a P1388 or P1389 code? Also wondered about a failing ignition switch but that doesn't seem to fit the symptoms as near as I can tell.

If anyone has any thoughts, I'm listening. Failing that, if it happens again I'll swap out the ASD relay and see if there's a contact problem or maybe a bad relay. Can't find any other scenario that makes sense.

Thanks in advance.

 

[Luke Fuchs]

Try the overflow valve on the return fuel line coming out the vp44.

 

[spacecadet]

Try the overflow valve on the return fuel line coming out the vp44.

Thanks Luke. When I unscrew the bolt from the banjo fitting, what am I looking for? Is the valve inside the fixing bolt? Will a failed valve be apparent by inspection or do I need to test it in some way?

 

[spacecadet]

Thanks Luke. When I unscrew the bolt from the banjo fitting, what am I looking for? Is the valve inside the fixing bolt? Will a failed valve be apparent by inspection or do I need to test it in some way?

Found the answers with a little searching - the valve is inside the banjo fitting and can be tested with a little air pressure. Looking for leakage back toward the tank.

 

[JR]

If you have instant fuel pressure verified by a known good gauge it's unlikely your relief valve is bad. Anything that allows air into the system would require the low pressure side to be bled out. Lower than normal or no fuel pressure is an indicator of air in the low pressure side.

Depending on year of truck you may have a crank or cam sensor going tango uniform. They don't always set a code when intermittent and can also cause a no start. An intermittent tach (or none at all) is one indicator.

 

[DavidC]

Signature shows 01.5 so no crank sensor just cam.

Dave

 

[MGrantham]

Went to drive off on a trip on Friday, engine cranked, fuel pressure at filter, dash display normal but no start. Tried 3 times for about 2 seconds each. Verified fuses and then queried codes - none thrown. Went back out and truck started right up, and did so every time on the 3 day trip. Nothing like a little drama to start a road trip.

Truck gets driven regularly and hasn't had any engine issues at all in 150,000 miles. I've searched TDR posts on "no start" but haven't found exactly this situation. Looking through the service manual, it seems that a faulty ASD relay could cause this situation, but wouldn't that throw a P1388 or P1389 code? Also wondered about a failing ignition switch but that doesn't seem to fit the symptoms as near as I can tell.

If anyone has any thoughts, I'm listening. Failing that, if it happens again I'll swap out the ASD relay and see if there's a contact problem or maybe a bad relay. Can't find any other scenario that makes sense.

Thanks in advance.

I had a bad VP44 when this happened

 

[Boondocker]

I have pretty much the same problem except my truck died while on the highway as if it ran out of fuel. Unable to restart since. The truck ran perfectly before it quit, no symptomatic behaviors. I've since replaced the VP44, all the fuel lines (Air Dog to injection pump and to tank), and replaced the fuel pressure gauge, which is plumbed into the fuel line to the VP44. Pressure is good (15 psi).

Any diagnostic advice?

 

[DavidC]

https://www.bluechipdiesel.com/troubleshooting-1

Dave

 

[spacecadet]

The End of the Story: VP44 was replaced, along with overflow valve in fuel return line. This fixed the problem until I reconnected my fuel pressure gauge line at the test port. Then it returned worse than ever. I suspect a leak developed with electric gauge sender head or hose, and replacing them both fixed the problem. About 3 weeks later, that gauge was showing 6psi at idle (as compared with 8psi for the preceding 3 years) and 2-3 psi at WOT. Not good for the new VP44. Fuel tank dropped, cleaned and pump/sender replaced. My mechanic said it was nearly plugged and was done for as a pump. Pressures are now 16psi at idle and 12 at WOT. This confirmed the TDR opinions that the in-tank pumps last about 100K.

It was definitely a process to fix this, but worth it as the truck is in perfect condition (a travel vehicle, not a daily driver) at 150K and I have no interest in taking out a second mortgage to buy a new one. Thanks to the forum members who helped out with this - priceless!