P0087 Fuel pres to Low Anyone have this issue?

sorry for digging up an old thread but my buddy has been having this code for quite some time so I'm trying to help him with it. He has an 06 vin 2 and has been getting this code on the stock tune only while towing when it's hot out. I've yet to log it and see exactly what happens with his pressure when it sets the code. We replaced the fuel line by the tranny and tomorrow I'm going to bottle test his fprv. I want to see what his desired and actual pressures are and something I wanted to log and test is to turn limp mode off and let it set the code and see if the pressure dips and recovers immediately or if the pressure stays below desired. I'm just wondering how safe it would be to disable limp mode or turn this code off?
This code is so widespread and so often not fixed that it makes me wonder if people aren't entirely on the wrong track. I've read where cp3's, injectors, fprv's, and lines have been replaced along with adding lift pumps and they still get this code. Makes me wonder if this isn't an ecm issue or something. I read a thread where someone logged it and their desired pressure was 33k. My understanding is that the CP3 can only make 26K correct?

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Originally Posted by 0rion

sorry for digging up an old thread but my buddy has been having this code for quite some time so I'm trying to help him with it. He has an 06 vin 2 and has been getting this code on the stock tune only while towing when it's hot out. I've yet to log it and see exactly what happens with his pressure when it sets the code. We replaced the fuel line by the tranny and tomorrow I'm going to bottle test his fprv. I want to see what his desired and actual pressures are and something I wanted to log and test is to turn limp mode off and let it set the code and see if the pressure dips and recovers immediately or if the pressure stays below desired. I'm just wondering how safe it would be to disable limp mode or turn this code off?
This code is so widespread and so often not fixed that it makes me wonder if people aren't entirely on the wrong track. I've read where cp3's, injectors, fprv's, and lines have been replaced along with adding lift pumps and they still get this code. Makes me wonder if this isn't an ecm issue or something. I read a thread where someone logged it and their desired pressure was 33k. My understanding is that the CP3 can only make 26K correct?

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Yeah. I'm not sure what our stock pumps "can" do. But stock Max is 26k psi or 180Mpa. And since my last post in this thread I now have TTS dual lift pumps and I am running 100% Bio, and haven't seen the code since ...

I'm going to bump this one more time because he's still having problems with it. He took the truck to a shop at one point and they replaced the cp3 and a couple of injectors. Issue went away for a short time but is now back and does it now whether he's towing or not and no matter what the temps are outside. Anything past about half throttle and it throws 0087 and limps. Did the bottle test and that was all good. Injector balance rates were within spec. Log shows desired pressure at ~25k and actual is 10-12k. All the rubber lines on the fuel lines have been replaced and a new fuel cooler put on.

I had the same thing happen to me on a truck I was tuning. The rail pressure would drop down less then 10k. I shimmed the FRPV and the code never came back.

There's always the possibility that a bad CP3 was installed. Or maybe just a bad regulator inside the CP3.

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Originally Posted by garrettg.bpd

I had the same thing happen to me on a truck I was tuning. The rail pressure would drop down less then 10k. I shimmed the FRPV and the code never came back.

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did it pass the bottle test? His dumped zero fuel. I just don't see how that fprv can be the culprit if it's not releasing fuel.

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Originally Posted by bballer182

There's always the possibility that a bad CP3 was installed. Or maybe just a bad regulator inside the CP3.

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is there a way to test the cp3? Man.....I sure hope that isn't it. That's an expensive part to have a lemon out of the box.

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Originally Posted by 0rion

did it pass the bottle test? His dumped zero fuel. I just don't see how that fprv can be the culprit if it's not releasing fuel.

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this test needs to be done under pressure. with the DVT controls, command max pressure and see if it leaks

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Originally Posted by 0rion

is there a way to test the cp3? Man.....I sure hope that isn't it. That's an expensive part to have a lemon out of the box.

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same as above. command max pressure and see if it can do it or does it fall sort

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Originally Posted by LB72004

this test needs to be done under pressure. with the DVT controls, command max pressure and see if it leaks




same as above. command max pressure and see if it can do it or does it fall sort

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I guess where I have trouble with the fprv is if the pressure dropped and it limped the truck wouldn't there have been fuel in the bottle? Where else would it go if the fprv was bad?

I'm starting to wonder if it's an injector issue. He looked up his work order from when he had the work done and that guy only replaced 1 injector so it would make sense to at least trouble shoot those to see if there's a problem. I have to read and figure out how to troubleshoot the injectors with the DVT controls. I saw I can control the rail pressure and each injector with the controls but I'm not sure what PIDS to log and what I'm looking for as far as a bad injector.

You can't troubleshoot a high return rate electronically. You have to do a return rate test by measuring how much fuel the injectors are returning.

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Originally Posted by JoshH

You can't troubleshoot a high return rate electronically. You have to do a return rate test by measuring how much fuel the injectors are returning.

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do you know what the return rate is supposed to be? I've read conflicting amounts online. I think we're down to where we have to troubleshoot these. There's just not much else left to do. You test the return rate with hoses off the injector return lines into cups and then crank (but not start) the motor for 15 seconds correct? Then measure the returns from the injectors.