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Ask -Brad- Your Own Question
-Brad-
-Brad-, Dodge Dealership Tech
Category: Dodge
Satisfied Customers: 7835
Experience:  16 Yrs Chrysler/Dodge Technician. ASE Master Certified(L-1)
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I have a trouble code on an 08 6.7L cummins in an 08 ram

Customer Question

I have a trouble code for p1012 on an 08 6.7L cummins in an 08 ram 2500 4x4. New injectors, lift pump, hpfp.
Submitted: 1 year ago.
Category: Dodge
Expert:  -Brad- replied 1 year ago.

Good evening an welcome to JustAnswer!!

Have you done any diagnostics on it or just replaced the injectors, supply and injection pumos and still have the issue? The code you have is P1012-FUEL PUMP DELIVERY PRESSURE TOO HIGH so the pressure is staying too high. If the actual pressure is fine I would replace the fuel psi sensor... If it really is high I would check the return line to the tank and see if it's punched or blocke somewhere..

I hope this helps,

Brad

Customer: replied 1 year ago.
I get codes for low rail pressure(p0087) as well. I've been testing lift pump pressure and voltage and ground. All seems good. Tested lift pump flow rate, and I got 650ml in 10 second period by diverting lift pump pressure into a beaker. What I am seeing is 14psi to the hpfp with key on engine off, and less than 10psi with engine idling, and now my fuel pressure gage goes from 14psi with engine off, and as soon as the motor starts, my gage goes quickly to zero, as if the hpfp is sucking vacuum to on the fuel pressure supply hose. I've also swapped filter housings off of another truck of the same year make model and engine, with no change.
Expert:  -Brad- replied 1 year ago.

Thanks for the reply!!

As long as you are getting 500ml in 10 seconds you are fine.. Now if you erase the codes when do they come back? Under a load or on startup? Have you monitored the fuel psi with a scantool compared to desired/actual to see if there is there is a issue or not? If you have a donor vehicle that you are borrowing parts off of then swap the common rails to see if you still get the codes..

Talk soon,

Brad

Customer: replied 1 year ago.
We swapped fuel rails, and feed tubes off of known good truck, no change in low rail pressure. My p1012 comes on on startup after clearing the code. My rail pressure shows 11k at idle on my heads up tuner.
Expert:  -Brad- replied 1 year ago.

11k @idle is way too much, you should only have 6k @ idle.. IS the engine making a chattering noise? How does it run? And does only the P1012 come back or both the P0087 and P1012 come back on start up? When did this issue start?

And are you sure the return line to the tank it not blocked?

Customer: replied 1 year ago.
Not sure about the return line, I can check it in the morning. The only code that I have been seeing while briefly starting it and cycling the key to check pressure is p1012. P0087 hasn't come up since this morning when I was idling it to warm it up.
Expert:  -Brad- replied 1 year ago.

Check the return line in the back of the head to the filter and to the tank.. Blow it out if you can and tell me what happens.. Also did this start after anything has been done to the truck?

Customer: replied 1 year ago.
The engine runs good. I haven't driven it today, as much of the day was spent changing the lift pump in the gas tank, and checking fuel pressures and swapping parts. Previously, I would get low rail pressure p0087, p1012, and p000f, truck would run fine, fuel pressure would be around 13-23k, truck would accelerate hard, then start to lose power as if it were running out of fuel. Once I let off, it would still run great, you could just tell it was losing full power at wide open throttle.
Expert:  -Brad- replied 1 year ago.

Darn it... When you had the tank out would have been a perfect time to blow the return line out.. So you have replaced the injectors, transfer tubes, lines, common rail, CP3 pump, fuel filer housing, and lift pump but still have the P1012? If so and it really does have 11k @ idle then the problem is the return line.. Not sure if you have any of the banjo fitting we have to test Cummins but if you have one run the return line from the back of the head to a old milk jug and see how it runs.. If it runs good your issue is in the line to the tank..

Keep me posted,

Brad

Customer: replied 1 year ago.
Pull the line off the back of the head, and blow which way?
Expert:  -Brad- replied 1 year ago.

Yes follow it to the fuel filter housing and blow toward the tank.. If you can't blow thru it then follow iot back and see what you find..

Expert:  -Brad- replied 1 year ago.

Diagram

Customer: replied 1 year ago.
Ok, the bypass hose comes off the back of the head, and bolts to the filter housing via banjo bolt, which is where bypass from the fuel rail joins on its way to the soft line to the tanks. Your saying pull the soft line there, and blow back toward the tank?
Expert:  -Brad- replied 1 year ago.

Yes you are correct.. The lines at the bottom of the fuel filter and see if you can blow to the tank.. Also run it into a jug and see how much fuel is returned and if the code comes back..

Customer: replied 1 year ago.
Ok, I pulled the bypass line off the top of the fuel pump, and disconnected the bypass line at the filter housing, and blew toward the tank. I reconnects at the fuel pump, then blew from the filter housing bypass(where I just blew) and blew back to the tank. I removed the bypass line banjo bolt at the back of the head as well, but I only see a bajo bolt at the surface of the head. Is there a bypass valve there inside the head? The banjo bolt was clear, no debri came out that I could see. Reinstall the banjo at the back of the head, and divert bypass at filter housing into a jug, clear codes and start?
Customer: replied 1 year ago.
I checked the bypass fuel flow rate coming off the fuel filter housing, and I got 450ml in 10 seconds.
Customer: replied 1 year ago.
I checked bypass flow rate coming out of the cp3, going to the filter housing, and got 150ml over 10 second period.
Customer: replied 1 year ago.
Are you going to respond?