0500 and No Start

[Diesel Gunner]

Arrived home last night at about 9:00pm. Attempted to start the truck at about 10:00am this morning and engine cranked, but no start. Usually hits on first turn. Checked for DTC's and got 0500 and 1693 (of course) in PCU and 1693 and 0177 on the ECU. Expected 0177 and 1693 since I have removed the engine mounted fuel filter and am running a Fass. I was surprised by the 0500 as I have not been spinning the tires but there is a possibility that the speed sensor has failed. However, I don't think that this should cause a no start. I did, however, notice that the Fass is not running on a bump (as I figured I would bump it two or three times to ensure that it had not somehow lost prime due to a leak sucking air) but my fule pressure gauge (Westach) shows that I have 15psi.

I will check that I have power at the pump, but it seems odd that I would have 15psi with no pump running.

Fuel hoses have been replaced in the past 2 years as the original Fass lines were showing age and cracking.

VP44 is original unit with 210K on it. I did not notice any issue with engine operation on way home last night (approximately 22 miles). I am fully aware that this is how a VP44 will die but I prefer to diagnose and not just throw parts at it.

I will also check wiring for speed sensor to ensure that I have power.

So, do any of you with an old truck like this have any ideas or suggestions?

Has anyone experienced this and what did you do to diagnose and repair>

Thanks in advance.

 

[Diesel Gunner]

Bump

 

[petersonj]

I did, however, notice that the Fass is not running on a bump (as I figured I would bump it two or three times to ensure that it had not somehow lost prime due to a leak sucking air) but my fule pressure gauge (Westach) shows that I have 15psi.

If you do successive bump starts without switching off the ignition key, the lift pump won't perform the 20 second run cycle after the first time.. Be sure to have the ignition switch off for a few seconds before making the bump start test.

Something surely is amiss if your fuel gauge reads 15 psi and your lift pump is not running.

I am fully aware that this is how a VP44 will die but I prefer to diagnose and not just throw parts at it.

So far, you have no codes to indicate a VP44 failure. I recommend that you continue to check out the lift pump system and prove there is fuel at the inlet of the VP44. You mentioned that you removed the engine mounted fuel filter and replaced the lift pump with a FASS. Where is the FASS lift pump mounted? Where are the filters? Is the lift pump still being powered directly by the ECM?

- John

 

[Diesel Gunner]

If you do successive bump starts without switching off the ignition key, the lift pump won't perform the 20 second run cycle after the first time.. Be sure to have the ignition switch off for a few seconds before making the bump start test.

Something surely is amiss if your fuel gauge reads 15 psi and your lift pump is not running.



So far, you have no codes to indicate a VP44 failure. I recommend that you continue to check out the lift pump system and prove there is fuel at the inlet of the VP44. You mentioned that you removed the engine mounted fuel filter and replaced the lift pump with a FASS. Where is the FASS lift pump mounted? Where are the filters? Is the lift pump still being powered directly by the ECM?

- John

Fass is mounted on right frame rail. Filters on pump (Titanium Series). Nothing was touched or changed between my return home and attempt to restart the following morning. I have checked the fuse and the relay which test good. but no power to the pump. Checking wiring now.

 

[Diesel Gunner]

OK, no power to the FASS. Fass does run when I powered it direct from battery. Still unable to find reason for no power at connecter at FASS.

Cracked #1 injector line and cranked engine and got no fuel?

 

[petersonj]

There are two independent circuits inside the relay. The ECM or a fused switched circuit needs to activate the coil part of the relay. Unswitched fused power from the battery will supply voltage to the switch part of the relay, which in turn will close and provide voltage to the lift pump.

I wouldn't worry about starting the engine until the above is figured out. When you do figure it out, crack the banjo fitting at the inlet of the VP44 with the lift pump running. You should see lots of fuel pouring out. Once you get to that stage you can crack 3 injectors lines at the head for bleeding any air out of the high pressure lines - I usually just do three that are easily accessible.

- John

 

[Diesel Gunner]

Problem solved. Turned out is was the FASS relay. Cycled he FASS 4 times and cracked an injector line and it fired right off.

 

[Ozymandias]

There are two independent circuits inside the relay. The ECM or a fused switched circuit needs to activate the coil part of the relay. Unswitched fused power from the battery will supply voltage to the switch part of the relay, which in turn will close and provide voltage to the lift pump.

I wouldn't worry about starting the engine until the above is figured out. When you do figure it out, crack the banjo fitting at the inlet of the VP44 with the lift pump running. You should see lots of fuel pouring out. Once you get to that stage you can crack 3 injectors lines at the head for bleeding any air out of the high pressure lines - I usually just do three that are easily accessible.

- John

I only cracked one injector line at the pump all my life and they always started fine and cleared idle within a couple seconds.