i dont know what to do here fuel problems

[super diesel]

Try turning the truck on without starting it. Unplug the FPR and plug it back and listen to see if at any point you get any sort of humming sound from it. Also listen to see if it does any clicking on and off at the same time.

 

[mch646]

OK and I'm going to shim the fprv tonight and do u k ow what thread size the bolts on the Turbo intake horn are I droped one last time and found it but would be nice to have extras around

 

[mch646]

ok just went out turned the truck on not running and unplug and plug it back in when power goes to it i can hear a humming sound.

 

[super diesel]

The bolt should be a M6x1. Measure its length (if you don't have a metric scale just measure the threads in standard and multiply it by 25.4 to get the metric length) in mm. The cap inside the FPRV is a 6mm metric hex IIRC to get to the spring and needle valve. Once you pull it all apart, carefully inspect the end of the needle valve for cracks too (with a magnifying glass if you have one). When you re-install the turbo horn, put the bottom bolt in the horn with some grease or something to hold it in place. I always take the alt. and put it off to the passenger side and lift up on the wiring harness (carefully), and thread a 3/8" 10mm socket on a universal joint with 2 6" extensions under everything back to this bolt to loosen OR tighten it. I always remove it with or return it with the horn.

 

[super diesel]

ok just went out turned the truck on not running and unplug and plug it back in when power goes to it i can hear a humming sound.

Sounds like it's working. Good deal.

 

[mch646]

i am really hope that the fprv is the problem ha and what about tigging the end of the banjo bolt shut? heard of that as well. and looking online i heard m4 washers fit perfect so ill grab a couple of those. but how many 1 2 3 4 lol

 

[mch646]

Ok I shimmed the fprv and still the same symptoms talking to gillette diesel and dimitri I was told to do a injector return rate test because one bad injector can drop duel fuelers i guess and supposedly there is a sensor for the fuel pressure regulator in the cp3 that could be bad too I was told

 

[mch646]

Bump ?

 

[super diesel]

Did you examine the FPV for any cracks? Also in post #36 I was wondering if you had done a bottle test for the return rate. I also hope you cp3 isn't getting a lot of "blow by" which wont allow it to compress the fuel as much (sort of like when a piston ring gets a lot of blow by from wear). The cp3 pistons don't have any rings, so when they get worn enough,,,,,,One other thing to wonder about is if there are any soft lines before you lift pump that could be collapsing some during a high fuel consumption rates. If there is any soft lines before the pump, make sure there not to soft.

 

[mch646]

No bottle test yet which return line do ya want me to hook in to

 

[mch646]

And did not see any cracks on fprv

 

[TrentNell]

No bottle test yet which return line do ya want me to hook in to

On the Lb7's you have to make test lines to do a proper return rate test , basically you have to isolate the returns from each cylinder head into 2 beakers , pull the main injection fuse and crank the truck over for 10 secs and measure the amount of fuel returned , the spec is no more than 20 ML , but normal is around 12-15 ML.

 

[dwax]

I had almost the exact same symptoms on my LMM. There is a small check ball on the LMM fuel filter assy that opens when you screw on the filter. It was gummed up and somehow had trash in it. I cleaned it and put a new filter on and it ran perfect. I know you have an LB7 and im not sure if you have ruled out the filter but may be worth a check.

 

[mch646]

Alright I will look for the return lines and run the return rate test. Then I don't know if it would he that check ball buy I will look into it.

 

[mch646]

Hey Trent where are the return lines for each cylinder head? And another thing all my tunes have a large us for easy starting while cranking could this mess with the return rates

 

[sweetdiesel]

Hey Trent where are the return lines for each cylinder head? And another thing all my tunes have a large us for easy starting while cranking could this mess with the return rates

DS in on the back of the head.......PS is on the front

PS you will have to some how tie into the line further down from the head.
i dont remember if there is a hose or its all hard line on a stock truck? but its tough to get at the head as it is behind the alt bracket.

 

[mch646]

OK ill look at them tomorrow

 

[super diesel]

Bingo. You can cut the return lines at the banjo bolt which are at the junction block where you got into the FPV and then reconnect them with fuel hose when your done. Makes testing latter if needed easier too. Maybe this is way off according to others ideas but this is the way I do it. Your results may vary.

 

[mch646]

Since they are low pressure returns I'm gonna cut them put a t fitting in and just plug them when not running a return test

 

[sweetdiesel]

Bingo. You can cut the return lines at the banjo bolt which are at the junction block where you got into the FPV and then reconnect them with fuel hose when your done. Makes testing latter if needed easier too. Maybe this is way off according to others ideas but this is the way I do it. Your results may vary.

Michael

I Its been so long since ive seen the stock lines

Testing is easy with this fuel block