LBZ Fuel Pressure Problems

CaptPhil

CaptPhil

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Sep 10, 2011
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Ne-max said:
Ya. It launched great at 23000ish psi. Then dropped rail and doggish the rest of the track. Ran a 8.21 at 88mph
Click to expand...
Well then your pressure sensor is giving you incorrect readings, because your truck would not run that fast with only 7500psi. I don't doubt it is losing pressure, but it isn't going that low.

When I was getting my tuning sorted out I had a tune that would lose rail to 12k, the truck would barely run, sputter bad, white and black smoke.

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Awenta

Awenta

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Sep 28, 2014
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CT
That comes up as a screenshot. No video, just me?

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CaptPhil

CaptPhil

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I looked at the logs. Hard to say exactly where the issue lies, but the truck is definitely losing rail pressure hard, and staying down. Compounding the issue the pulse going to 3400us due to the low rail, which certainly wont let it come back up and recover. My guess is a regulator tuning issue, but a bad pump or low pressure supply issue is likely as well.

It is surprising the truck is running that well considering how low the rail is going.
 
juddski88

juddski88

Freedom Diesel
Jul 1, 2008
4,656
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63
Chesterfield, Mass.
Ne-max said:
Controller or the whole set up? Just run the valley one?
Click to expand...

Yes.Take the belt off for a little bit too just to see if the same pressure drop happens. It is plausible there is a tuning issue causing it too, as stated, but this is a quick check to rule out the 2nd cp3 itself. It could also be some really messed up injectors if youre seeing more smoke at idle and running rough. If I understand correctly, this is a new issue that has occurred and the truck had been acting great up until now with no other fuel pressure isues?
 
Ne-max

Ne-max

I like turtles
Nov 15, 2011
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Lincoln, Ne
I just built my motor. Have a 1000 miles on it now but that was the first time really getting on it. The injectors are new from exergy. I'll give that a try.
 
Ne-max

Ne-max

I like turtles
Nov 15, 2011
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Lincoln, Ne
CaptPhil said:
I looked at the logs. Hard to say exactly where the issue lies, but the truck is definitely losing rail pressure hard, and staying down. Compounding the issue the pulse going to 3400us due to the low rail, which certainly wont let it come back up and recover. My guess is a regulator tuning issue, but a bad pump or low pressure supply issue is likely as well.

It is surprising the truck is running that well considering how low the rail is going.
Click to expand...

Josh said same thing. Defintly a pump issue. Now to see if its a for, cp3 or controller
 
Ne-max

Ne-max

I like turtles
Nov 15, 2011
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Lincoln, Ne
Big shot out to Husker Diesel. Swung by there after work. After some quick Diagnostics Jess found that my controller is for a lb7. Swapped in a lbz and that fixed it.
 
CaptPhil

CaptPhil

Active member
Sep 10, 2011
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Delaware
Ne-max said:
Big shot out to Husker Diesel. Swung by there after work. After some quick Diagnostics Jess found that my controller is for a lb7. Swapped in a lbz and that fixed it.
Click to expand...
Well then, didn't see that coming. I thought all the controllers were the same.

Fprs are different.

I bet the truck absolutely rolls now.

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