2015 RAM 3500 - Truck Will Not Start

[miller271]

Details on my truck: 2015 RAM 3500 with 6.7L Cummins 68RFE transmission.

Approximately 135K mileage

Following modifications:
DRD tune with MM3
FLO~PRO exhaust
EGR delete

Loaded the tune to my truck.

It started with no issue.

Installed EGR delete and FLO~PRO exhaust.

Afterward took it out on a drive roughly 7 miles round trip with o issues.

I came back, and at idle, the truck exhibited runaway diesel condition.

I couldn’t stop the engine.

This lasted approximately 30 seconds and engine shutdown (out of fuel).

I drained the oil, and it contained a mixture of diesel and oil.

Roughly 7 gallons total and replaced with fresh oil and filter.

Running my scanner, I am getting 2 codes, 00472 and 0088 (fuel pressure rail too high).

I replaced the fuel control actuator, and the engine will crank but will not idle.

Ray @DRD has been very supportive in answering all my questions.

I’ve also been working with experienced diesel mechanics.

He suggested I reinstall my stock tune and EGR items.

I would prefer not to do this if unnecessary.

Any suggestions would be greatly appreciated.

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[AK Bob]

It sounds like you are in good hands.

Not sure why it’s not starting now, wondering what your Actual Rail Pressure is when cranking.

I would set up the MM3 to read fuel rail pressure actual and desired.

Then with the key in the “run” position (do not attempt to start), you should see the MM3 display a low “Actual Rail Pressure” around 300psi or less and a “Desired Rail Pressure” of around 4,640psi.

Then crank the engine and see what the “Actual Rail Pressure” reads; it should reach the desired or slightly higher.


2014 RAM 3500 (Aisin) 3.73 4X4 Limited Crew Cab Long Bed DRW. Oil Bypass Filter, Fuel Filtration Kit, and 50 Gallon auxiliary fuel tank.

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[miller271]

Thanks, Bob, for responding to my post.

I just went out and checked my RP.

With the ignition switch on, I am reading around 50 psi.

When I crank the truck, it’s going up to 10000 psi.

Now could I possibly have a defective fuel rail pressure sensor?

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[AK Bob]

Yes, I would replace that next.

Unless someone comes up with a better idea.


2014 RAM 3500 (Aisin) 3.73 4X4 Limited Crew Cab Long Bed DRW. Oil Bypass Filter, Fuel Filtration Kit and 50 Gallon auxiliary fuel tank.

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[Chrisn162001]

Before replacing the pressure sensor, check rail pressure while cranking with FCA unplugged you should get around 26k psi.

If it reads 26k, your rail pressure sensor should be good.


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[Chrisn162001]

Sorry just read the whole post.

If you really got 7 gallons out of the oil change, check for leaking feed tubes or stuck open injector, but then again, if you had either, you’d have low rail pressure.


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[AK Bob]

Before you replace the pressure sensor check rail pressure while cranking with FCA unplugged you should get around 26k psi.

If it reads 26k your rail pressure sensor should be good.


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Great idea, have you tried this?


2014 RAM 3500 (Aisin) 3.73 4X4 Limited Crew Cab Long Bed DRW. Oil Bypass Filter, Fuel Filtration Kit and 50 Gallon auxiliary fuel tank.

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[miller271]

I disconnected the FCA, and the RP during cranking maxed out around 28000 psi.

It then settled back down to 12000 psi.

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[AK Bob]

I disconnected the FCA, and the RP during cranking maxed out around 28000 psi.

It then settled back down to 12000 psi.

Well, you have plenty of fuel pressure to enable starting.

This would lead me to think faulty camshaft or crankshaft sensor.

@Chrisn162001 any ideas or suggestions?


2014 RAM 3500 (Aisin) 3.73 4X4 Limited Crew Cab Long Bed DRW. Oil Bypass Filter, Fuel Filtration Kit, and 50 Gallon auxiliary fuel tank.

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[AK Bob]

Another thought, is the Throttle Valve stuck or commanded closed?

The TV should be unplugged anyway, and check to make sure it’s not stuck closed.


2014 RAM 3500 (Aisin) 3.73 4X4 Limited Crew Cab Long Bed DRW. Oil Bypass Filter, Fuel Filtration Kit and 50 Gallon auxiliary fuel tank.

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