P0087 low fuel rail pressure

[Jman]

Hello everyone well I’ve got a little issue you guys are probably talked about this 1000 times but I tried to find something about this issue and it’s pretty vague so I’m trying to find out a little bit more information to what’s going on with my 2011 common rail.

The problem that I’m having is when I start my vehicle in the morning my rail pressure tends to be about 6800 KPI as the vehicle warms up and I’ll begin to drive and get to my first stop light my fuel rail pressure drips down to 4200 KPI and it kind of fluctuates between 5540 and 4300 KPI then I get a check engine light. The rail pressure throughout the course of the day remains about the same it never gets above 5200 KPI. I am constantly having to clear the troubles with my mini max programmer.

currently I have a HS minimax and all the tuning software hopefully someone out there knows what’s going on with this vehicle I have replaced the FPC in the Injecion pump. I know it’s not a lift pump issue due to the fact that I have a velocity 200 lift pump and GR sump with Russell fuel lines so it’s not a fuel delivery issue it seems like it’s a CP3 issue all of the crossover tubes are all tight I have no fuel leaks any ideas?

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[Polaraco]

Hello everyone well I’ve got a little issue you guys are probably talked about this 1000 times but I tried to find something about this issue and it’s pretty vague so I’m trying to find out a little bit more information to what’s going on with my 2011 common rail.

The problem that I’m having is when I start my vehicle in the morning my rail pressure tends to be about 6800 KPI as the vehicle warms up and I’ll begin to drive and get to my first stop light my fuel rail pressure drips down to 4200 KPI and it kind of fluctuates between 5540 and 4300 KPI then I get a check engine light. The rail pressure throughout the course of the day remains about the same it never gets above 5200 KPI. I am constantly having to clear the troubles with my mini max programmer.

currently I have a HS minimax and all the tuning software hopefully someone out there knows what’s going on with this vehicle I have replaced the FPC in the Injecion pump. I know it’s not a lift pump issue due to the fact that I have a velocity 200 lift pump and GR sump with Russell fuel lines so it’s not a fuel delivery issue it seems like it’s a CP3 issue all of the crossover tubes are all tight I have no fuel leaks any ideas?

What kind of shape are the filters in?

Could you possible have a vacuum leak on the suction side? Typically the pump would be loud. Can you read the lift pump pressure?

How many miles on the truck?

Are you saying the rail pressure never gets above 5200?

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[Jman]

The filters are a fuel lab filters and the last time I changed it was about 2000 miles ago the filter doesn’t seem to have any effect on the rail pressure The left part fuel pressure is about 16 pounds on the low setting and the high setting it’s about 22 pounds and there’s no leaks because it has a sump pick up and return in the bottom of the tank. The return line that is now used from the rail is actually tied into the old fuel supply hard line that goes into the in tank fuel pump that is disconnected
The 5200 is just the idle in gear with the brake on normal operating pressure of the rail is 24 KPI when I get into a hard rail pressure seems to be fine as long as I’m not at an idol everything is working normally

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[Jman]

The truck has 148,000 miles on it

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[TexNeck]

Hello everyone well I’ve got a little issue you guys are probably talked about this 1000 times but I tried to find something about this issue and it’s pretty vague so I’m trying to find out a little bit more information to what’s going on with my 2011 common rail.

The problem that I’m having is when I start my vehicle in the morning my rail pressure tends to be about 6800 KPI as the vehicle warms up and I’ll begin to drive and get to my first stop light my fuel rail pressure drips down to 4200 KPI and it kind of fluctuates between 5540 and 4300 KPI then I get a check engine light. The rail pressure throughout the course of the day remains about the same it never gets above 5200 KPI. I am constantly having to clear the troubles with my mini max programmer.

currently I have a HS minimax and all the tuning software hopefully someone out there knows what’s going on with this vehicle I have replaced the FPC in the Injecion pump. I know it’s not a lift pump issue due to the fact that I have a velocity 200 lift pump and GR sump with Russell fuel lines so it’s not a fuel delivery issue it seems like it’s a CP3 issue all of the crossover tubes are all tight I have no fuel leaks any ideas?

Sounds like FCA (fuel control actuator) on the CP3. With the truck running unplug it quickly and this should max out CP3 and spike tail pressure. It’ll knock like a 12v as well. Plug it back in quickly since you don’t want to keep the pump wide open for too long.

If if you’d rather just remove it to do the shake test it’s only 3 T10 (I think) torx to remove.

if you need to replace buy from Cummins and not a dealer. When I did my 5.9 it was $50 cheaper from Cummins then dealer

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[Jman]

Sounds like FCA (fuel control actuator) on the CP3. With the truck running unplug it quickly and this should max out CP3 and spike tail pressure. It’ll knock like a 12v as well. Plug it back in quickly since you don’t want to keep the pump wide open for too long.

If if you’d rather just remove it to do the shake test it’s only 3 T10 (I think) torx to remove.

if you need to replace buy from Cummins and not a dealer. When I did my 5.9 it was $50 cheaper from Cummins then dealer

I replaced the FCA about a year and a half ago because I thought the same thing, it didn’t change the drop in rail pressure at all still does it, at this point I’m installing a new 14mm CP3 and BBI stage 3 injectors in a couple weeks hopefully that cures the problem

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[Polaraco]

The filters are a fuel lab filters and the last time I changed it was about 2000 miles ago the filter doesn’t seem to have any effect on the rail pressure The left part fuel pressure is about 16 pounds on the low setting and the high setting it’s about 22 pounds and there’s no leaks because it has a sump pick up and return in the bottom of the tank. The return line that is now used from the rail is actually tied into the old fuel supply hard line that goes into the in tank fuel pump that is disconnected
The 5200 is just the idle in gear with the brake on normal operating pressure of the rail is 24 KPI when I get into a hard rail pressure seems to be fine as long as I’m not at an idol everything is working normally

ON THE CONTRARY. IF THE LIFT PUMP IS NOT DELIVERING SUFFICIENT FUEL, YOU CAN HAVE LOW RAIL PRESSURE.

IT'S VERY POSSIBLE TO HAVE A VACUUM LEAK AT THE PUMP. IT DOESN'T HAVE TO LEAK FUEL TO HAVE A VACUUM LEAK. I HELPED A FRIEND OUT WHO INSTALLED HIS OWN AIR DOG. HE OBER TIGHTENED THE SUCTION FITTING AND CRACKED THE PUMP BODY. THE OUTCOME WAS SIMILAR.

AFTER 55+ YEARS OF DOING THIS STUFF, I'VE SEEN IT EVEN ON A GASOLINE ENGINE WITH A MECHANICAL PUMP. KINKS IN LINES CAN CAUSE IT TOO. A LOT OF THESE PROBLEMS ARE CAUSED BY THE INSTALLER. THERE ARE MECHANICS AND THEN THERE ARE REAL MECHANICS. IN TIME YOU'LL KNOW MORE ABOUT ME BEING A NEW MEMBER AND ALL.

Sounds like FCA (fuel control actuator) on the CP3. With the truck running unplug it quickly and this should max out CP3 and spike tail pressure. It’ll knock like a 12v as well. Plug it back in quickly since you don’t want to keep the pump wide open for too long.

If if you’d rather just remove it to do the shake test it’s only 3 T10 (I think) torx to remove.

if you need to replace buy from Cummins and not a dealer. When I did my 5.9 it was $50 cheaper from Cummins then dealer

THAT'S WHAT I WAS THINKING TOO. I JUST NEEDED MORE INFO BEFORE PASSING JUDGEMENT

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[Jman]

I will check that out tomorrow, it is possible. Now I’m starting to think it might be the fuel lab pressure regulator, it only has low rail pressure surge when idling.
The regulator may be cutting back the fuel volume but not the pressure at low rpm. I am using atmospheric instead of boost line pressure control, I have the bypass spring set to 22 psi.
I have a fuel pressure sensor on the fuel filter deletion block and the pressure needle fluctuates between 15 and 17 psi at idle But then again when you put your foot into it fluctuates between 15 and 17 PSI as well. The system never goes below 15 psi from the fuel lab velocity lift pump in the low/normal setting, this pump has an internal pwm speed control based off secondary pressure.
I can however set the pump to high and see if that helps, I’ll update with my findings

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[Jman]

ON THE CONTRARY. IF THE LIFT PUMP IS NOT DELIVERING SUFFICIENT FUEL, YOU CAN HAVE LOW RAIL PRESSURE.

IT'S VERY POSSIBLE TO HAVE A VACUUM LEAK AT THE PUMP. IT DOESN'T HAVE TO LEAK FUEL TO HAVE A VACUUM LEAK. I HELPED A FRIEND OUT WHO INSTALLED HIS OWN AIR DOG. HE OBER TIGHTENED THE SUCTION FITTING AND CRACKED THE PUMP BODY. THE OUTCOME WAS SIMILAR.

AFTER 55+ YEARS OF DOING THIS STUFF, I'VE SEEN IT EVEN ON A GASOLINE ENGINE WITH A MECHANICAL PUMP. KINKS IN LINES CAN CAUSE IT TOO. A LOT OF THESE PROBLEMS ARE CAUSED BY THE INSTALLER. THERE ARE MECHANICS AND THEN THERE ARE REAL MECHANICS. IN TIME YOU'LL KNOW MORE ABOUT ME BEING A NEW MEMBER AND ALL.



THAT'S WHAT I WAS THINKING TOO. I JUST NEEDED MORE INFO BEFORE PASSING JUDGEMENT

the pump is whisper quiet until I set it to high, I’ll check it out, I too say the same about electricians, had a perfect example of that this week.
I am only a weekend wrencher, Electrical contractor by week, but I am thorough, kind of a perfectionist, usually spare no expense and have owned cummins trucks for 23 years, different makes and models. You and others like you are the reason I’m here and I appreciate your knowledge.
Glad to be onboard.

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[Polaraco]

the pump is whisper quiet until I set it to high, I’ll check it out, I too say the same about electricians, had a perfect example of that this week.
I am only a weekend wrencher, Electrical contractor by week, but I am thorough, kind of a perfectionist, usually spare no expense and have owned cummins trucks for 23 years, different makes and models. You and others like you are the reason I’m here and I appreciate your knowledge.
Glad to be onboard.

OK Sparky. LOL I did industrial, lots of utilities in the north east. Including some nukes plants. (No wonder I'm so F'd up)

I was the one who had to get into some other ungineers head and try to figure out what they were thinking. Messed with 2M on down. I preferred low voltage. LOL

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