LB7: Diagnostic help

[dirtydmax]

Need some fresh eyes and people smarter than I with this one before I start tearing my built motor back down.02 lb7 trip cp3 with fingers controller,getting full rail pressure at crank and also setting a crank position code (0336)3.5-4.5 volts at fpr plug.fprv is removed for the 3rd cp3 inlet in the fuel block.Switched the cam and crank sensor to make sure I didn't mix wires and have swaped the valley fpr as well as tried each pump by them selves with the same outcome.Its trying to fire but will not and when its chugging almost sounds like a fuel knock.sorry for the novel but wanted to give as much info as I could,Starting to think this block is cursed.Thanks in advance.

 

[Huffy67]

Getting the crank position code is not good. Prob why it won't run. As to what is wrong with it, idk...


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[dirtydmax]

Getting the crank position code is not good. Prob why it won't run. As to what is wrong with it, idk...


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This thing has kicked my ass all over the place from the start so i am not surprised,not sure if the reluctor is the orig from this motor but its either a lb7 or lly.

 

[Huffy67]

Hmm. Maybe your reluctor and your sensor or ecm do not speak the same language.


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[dirtydmax]

Trying to figure out what can cause these 2 codes as they are prob causing the no start.Im lost with this one.

 

[dirtydmax]

If I was 180 out on the timing what would the symptoms be?

 

[Stancedlb7]

loose reluctor ring????

 

[dirtydmax]

loose reluctor ring????

Everything was snug when installed,double checked everything and used mcrat timing thread to setup but its possible I fudged it.Should have tried to start it before fully dressed.

 

[dirtydmax]

Swaped out crank sensor and BOOOM fired right up but still max rail at 26k idle so it sounds like a pos ford at -20 starting.watched with v2 and truck is commanding 100% fpr.Swapped out ficm as well to eliminate probs.What could cause this?

 

[Huffy67]

Nice!! Tuning issue?


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[dirtydmax]

Nice!! Tuning issue?


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No fn clue why I am getting max rail at idle.checked the fpr plug and getting a 3.5v which I have read is wide open,should be 1.7v at idle.so all 3 pumps are full blast with 100% overs,Sounds scary!

 

[Huffy67]

Lol!! Are they stock lb7 pumps or what?
When I put the modded lbz pump on my lb7 I got it running before being retuned and it was the same way. Has to be retuned for the lbz fpr

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[THEFERMANATOR]

if its commanding full voltage to the regulator, then that means its trying to lower the pressure. more current equals less fuel, lrss voltage means more fuel. hence unplugging a regulator gives you max pressure. you said 3 cp3s with 1 unplugged, that would give you a runaway rail pressure condition.

 

[dirtydmax]

all stock pumps but a miss match batch,1 lbz reg on the top.

 

[dirtydmax]

if its commanding full voltage to the regulator, then that means its trying to lower the pressure. more current equals less fuel, lrss voltage means more fuel. hence unplugging a regulator gives you max pressure. you said 3 cp3s with 1 unplugged, that would give you a runaway rail pressure condition.

All 3 are plugged in,Was unplugging pumps to eliminate starting issues but once it fired plugged them in with same results.I am wondering if I have 1 stuck reg causing the issue.I also have a lbz reg clocked about 40-45 deg for fitment,could that be the bad apple?Thanks for the help Firm!

 

[THEFERMANATOR]

i would think all the regs need to match. lb7 and lbz regs use drastically different amp vs flow charts in the lower flow areas. sounds like you found your problem, get matching regs, and scale the current table to match.

 

[dirtydmax]

Would 1 lbz reg cause max rail or should I be looking for 1 that is stuck?I plugged 1 in and watched the plunger pull all the way down as in towards the plug.is that open or shut?

 

[Fingers]

Lack of voltage causes the max rail pressure.

 

[Fingers]

Not sure about your drive setup, but go to spinning only one pump and see what happens.

You should see about 6 volts across the pins at each FPR.

If no voltage, check the fuse in the controller. Triple controller can take up to a 10 Amp fuse.

 

[dirtydmax]

Not sure what is ment in across the pins.On the fpr pigtail on the motor harness i get 0.0v on one side and 4.5-4.6 volts on the other.not sure what this means.