Have a no start condition with my 2000 Dodge Ram 2500 Quad 4x4 Cummins Diesel (approx 545k miles I think...been a while since it was running).

 

Went through the “BLUE CHIP DIESEL – NO START TESTS”. Truck started when I hot-wired the VP44, which stunned me! 

 

But before the hot wire: initially had 12.7v on pin #7 of VP44 plug (with respect to battery…had the charger on the batteries) in “run” key position, dropped down to 12v while cranking (“start” position). Testing between pin #6 (ground) and pin #7, had 12.7v with key in “run” position…then in “start” voltage dropped down to 6v and fluctuated between 6v and 11v not coming back up to 12v until key was back in “run” position.  With negatives of both batteries disconnected, Fluke Mod 325 meter didn't register any resistance between #87 at the Fuel Pump relay and pin #7 on the VP44 plug (but in no-load condition...don't know how to do that).  

 

Had the ECM re-built by Car Computer Guys in November 2023.  I was having troubles with my PureFlow lift pump (RP-100). Subsequent to the ECM re-build, PureFlow replaced the lift pump on warranty.  Since my lift pump difficulties, fuel mileage dropped significantly (trips I was getting 19.5-20 mpg barely achieved 15 mpg).

 

The blue wire with red tracer was already cut & capped.  Even though I don’t remember doing it, makes sense I may have done that back in September 2013 while diagnosing another no start…turns out I had a bad Crank Shaft Position Sensor. 

 

I replaced the VP44 with a rebuild in August 2013 at 325k miles. 

 

Probably have more than one nail in my tire...so perhaps new VP44, injectors (they have 545K, original equipment), and???

Don’t know what to do next.  What are the next tests I should do?  Some helpful advise would be greatly appreciated!

 

I would double check Pin #6 (ground) test.  This test should produce a steady voltage.  I would use a test lamp with an incandescent bulb, if possible.  This will place a small electrical load on the circuit being tested.  Pin #6 is connected to Splice #168 which splices into two ECM grounds and an engine block ground.  Splice #168 has been know to be troublesome.

 

So, try retesting Pin #7 to Pin  #6 with a test lamp - ignition on for the first test, engine cranking for the second test.  The lamp should dim slightly, but remain steady for the engine cranking test.  If the test fails, then keep one lead of the test lamp on Pin #6 and connect the other lead to a battery positive post.  Note the results of the test.

 

Are there any DTC's stored?   If so, knowing what they are could help with troubleshooting.

 

Your high mileage injectors should be replaced.  The injectors are not the cause of your no-start, but you have gotten a good service life from them - time to replace them.

 

Using a multi-meter to check resistance at connectors is a common practice, but it has its limitation, i.e., a single strand of wire in multi-strand wiring maybe the only connection, which can falsely indicate that a circuit is good.  This is why I use a test lamp whenever I can - to place a small electrical load on the circuit during the test. 

 

- John

 

Problem is resolved...but it took me a ridiculous amount of time!

There were multiple problems:

First, the VP44 had failed - well, some part of it. Doing the hot wire method described by Bluechip Diesel, I was able to get it to start, but barely. Didn't run well. My mileage had gone down 20%+ leading up to the no start so I was not surprised.

Second, I was getting erratic voltage to the lift pump (and it's set up with a relay triggered by ECM and fused power to the Raptor lift pump) and occasionally erratic to the VP44. So pulled EMC and sent off to Auto Computer Specialists for ECM diagnose and repair. That was done nicely and they recommended attention to the wire harness. (BTW, forgot to put my ECM back to factory settings with the Smarty tuner the previous rebuild attempt from another service, so now not able to use the smarty to put the high-idle function back on...anyone know how to reach anyone at Smarty or former Smarty to do a one-time unlock?)

Third, pulled wire harness and sent to Auto Computer Specialists. They did a really good job (seems to me) cleaning the harness and replacing what needed to be replaced. Several wires, including a ground, were noted as being replaced.

Fourth, self created problem...while removing the re-built VP44 to replace the tappet cover gasket while waiting for the wire harness rebuild, got distracted after removing the timing gear nut, pulled the VP44 and heard the ting-ting-ting noise of the lock washer falling down into the case. Well, I was leaking out the front crank seal so that was the impetus to replace with a seal & sleeve kit, which I should have done anyway, and retrieve the lock washer.

Truck has been running well. Have a bunch of work to get to after current work project I'm on finishes up (ball joints, steering linkages, rear door latch, and cleaning off the Doug-fir sap that is covering the truck after being dead under one of our trees through a season). Also want to replace injectors since, well, these have now over 550k on them!

Glad to hear the truck is up and running well. Looks like your first VP44 lasted about 100,000 miles longer than the second one.

My first VP44 failed at 87,000 miles and the second one is still going at 397,000 miles on the odometer, so 310,000 miles on the second Vp44. I won't be surprised to see a failure in the near future, but that's okay - it has been reliable and has had a long life.

• John

My guess is the BlueChip diesel VP44 rebuild would have happily kept going for many more miles absent fuel starve problems caused by several repeated Raptor lift pump failures.

Not sure going forward with new Oregon Fuel Injection VP44 rebuild what I'll do different. I have a mechanical fuel pressure gauge in the cab right now (don't really like the idea even thought I sealed the firewall penetration with fire caulk) and putting two or three gauge pillar mount is on the to-do list. Have a low pressure light in the cab but sending units failed quickly (mounted at the VP44, I didn't know until more recently that's a common problem; now I have a sending unit mounted off of a T after about 6' of flexible fuel line) so in the end that didn't help me much.

There are a couple of things you can do for better reliability for the VP44.

First, get over the idea that 14 psi lift pump pressure is needed to ensure there is always return fuel flowing to the fuel tank from the VP44 (if you still believe this). The lift pump pressure has no influence whatsoever on the quantity of return fuel from the VP44. The VP44 return fuel flow is controlled only by the VP44's internal vane pump and its regulating valve (over 100 psi) and the 14 psi overflow valve. Being that the internal vane pump is of fixed displacement design, the pump's output flow is always the same at a given engine rpm - regardless of engine load or lift pump pressure.

When I performed VP44 fuel return flow testing, I installed a lift pump bypass circuit with a one-way check valve to demonstrate that turning off the lift pump did not change the return flow volume from the VP44. I did a 30 mile road test without the lift pump operating and the engine performed flawlessly under all operating conditions.

1. So, when I reconnected things after my testing, I thought why should I remove the lift pump bypass circuit with the one-way check valve? If the lift pump stops working, the bypass circuit would go into action and continue to feed the VP44 pump - a win, win situation. If a lift pump should fail on a road trip, my low fuel pressure indicator lamp would light to make me aware of a problem, but I could continue driving to a place to do the repair without harming the VP44.

2. For lift pump pressure sensor reliability (fuel gauge or warning light system) install a snubber and 24 inches of grease hose with 1/8" NPT fittings on each end. This arrangement will greatly increase the life sensors. I used a pressure switch for a warning LED light on the dash.

• John

John,

Thanks very much for the insights. I've been a little concerned about running the lift pump pressure so much higher than stock thinking there may be negative unintended consequences. Somewhere I had read higher lift pump pressure would lead to more return flow...didn't question it so thanks for clearing that up.

What are the specs on the check valve you used for the the bi-pass system?

I like your setup on the warning light.

Thanks,

Dave

Dave, this is what I used. There are lots of choices - just make sure that the free flow direction requires very little pressure differential to flow.

• John

Low pressure light - ISSPro EV2 programmable Fuel Pressure gauge.

I really like the low pressure light on the fuel gauge...hadn't ever noticed that was an available option.

Thanks, John, for the check valve info!

Dave

ISSPro EV2.

The ISSPro EV3 is bluetooth programmable and even more options.

Edited Thursday at 03:34 PM3 days by Mopar1973Man