Bad ECM/PCM?

[MrMerica]

4000-4500? I can barley feel the pressure with my finger. I get no spraying when I just crack the line it’s more of a slow seep.

[dripley]

The fuel I saw in your video is coming out of a line with an ID of around 1/16 of an inch, I dont know the exact ID on them. The fuel is being pushed thru 7 holes that are only 100th of an inch in the case of 7 X .010 injectors, 150hp. The injection event happens in milliseconds, how many someone smarter than me would know better. Most injectors should come set near 310 bar pop pressure. 310 X 14.5 psi equals 4,495 psi to pop the injector. 

 

The flow I saw in your vid is pretty much what I have seen out mine with lines loose. I get no spraying from mine since I back the nut all the way off. That being said I have never put my finger over the ends of the lines to feel any pressure they are under. 

Edited January 7, 2020 by dripley

[dripley]

Just add this, the line is not under constant pressure. It only ramps for the injection event since we have mechanical injectors.  All of that is done by the VP. Exactly how it does is over my head.

[Mopar1973Man]

VP44 is capable of minimum of 4,500 PSI at an idle to well over 20,000 PSI at WOT. If the VP44 PSG is damaged the the fuel pin will not be pulled enough to build pressure. Our VP44 pumps have 3 pistons working in a gang and pump at the same time to the distributor position its currently point at. 

 

 

[MrMerica]

Found the answer!

 

Turned out to be a dead VP that shorted out and killed a few relays on the way. Replaced the VP/relays and shes back up and running. Looks like the fuel we were seeing in the attached video was actually just lift pump pressure. From what I've gathered if your truck isn't making a mess while cranking with a line completely unseated then you may have a dead VP.

 

Thanks for all the help fellas.

[wil440]

On 1/7/2020 at 1:39 AM, MrMerica said:

4000-4500? I can barley feel the pressure with my finger. I get no spraying when I just crack the line it’s more of a slow seep.

Just for reference now you have a good vp don't put fingers over or anywhere near loose injection lines, high pressure fuel can penetrate skin/people very easily and it's supposed to not be nice, this is more important with pop testers but if you follow the golden rule of not going anywhere near you'll not be far wrong

[dripley]

Glad you got her fixed and it was an inexpensive fix.

[raymie.f]

just adding to what Wil440 said about fingers over fuel lines.. high pressure diesel going into the skin is a quick way to loose a hand.. if you don't have a weak stomach just do a google search for "high pressure injection injury". 

[Tractorman]

On ‎1‎/‎17‎/‎2020 at 8:27 AM, MrMerica said:

Turned out to be a dead VP that shorted out and killed a few relays on the way. Replaced the VP/relays and shes back up and running.

 

Thank you for posting the fix for your problem, but I still am not clear on the solution.  Did you replace the VP44 and some relays? or just relays.  Also, which relays?

 

Thank you,

- John

[MrMerica]

On 1/23/2020 at 12:43 AM, Tractorman said:

 

Thank you for posting the fix for your problem, but I still am not clear on the solution.  Did you replace the VP44 and some relays? or just relays.  Also, which relays?

 

I ended up completely replacing the VP44 and related relays. The VP44 shorted out and as a result popped 2x relays and 1x fuse. 

 

As for relays/fuses:

FASS relay (If you haven't installed a FASS its what bridges power/ECM signal/signal and power back to the FASS)

Fuel Pump relay under the PDC (right above the power outlet relay)

I also had to replace the Engine control 2 fuse.

 

Hope this helps! 

[Tractorman]

@MrMerica, thank you.  It is all clear to me now.

 

- John