LBZ Fuel Pressure Problems

[Ne-max]

Finally got to take my LBZ to the track last night. After logging I found out I am having a big fuel issue. In the 1/8 mile my rail pressure drops to 7500 right at about the 60ft mark. Desired is 27500. Stays in that area the whole way.

On to the next part. Since I finished motor it always had a haze at idle and some odd balance rates when my cts is reading 4500. If I bump up rail to 8000 in cleans up great and my balance rates are great.

When I got motor done I hooked up my isspro rail pressure gauge and it only reads 2300 when my cts reads 4500. So I unhooked isspro gauge and just ran the cts. Last night I hooked it back up and it did the same thing.

So what I am thinking is my computer is not getting the right reading from my rail pressure sensor but my isspro gauge is actually right. But at that it has me scratching my head cause if my actual rail is 7500 and computer is commanding 27500 shouldn't my fprs be open all the way and not effect performance? I am thinking its a wire issue but just seem odd. Any idears?

 

[ikeG]

What % are your regs running when its 7500rpsi?

 

[henery97]

Subd.FWIW my truck hazes at idle now & has some weird balance rates.

 

[Ne-max]

What % are your regs running when its 7500rpsi?

7.8%

 

[Harbin_22]

What's it show if you unhook the regulators?

 

[Ne-max]

What's it show if you unhook the regulators?

29000

I am running dual stock lbz pumps and 150% over injectors. Forgot to mention that

 

[juddski88]

Which controller are you using for the 2nd pump?

 

[Ne-max]

Which controller are you using for the 2nd pump?

Its a industrial kit

 

[JoshH]

Do you have a race valve or shimmed fprv?

 

[Ne-max]

Race valve. Just put in new rail and fitting cause it was leaking. Also. I though that was my issue

 

[Harbin_22]

Bottle test the race Valve.

 

[Harbin_22]

So when you log it, unplug the regulators, and it will show 29k?

 

[Ne-max]

So when you log it, unplug the regulators, and it will show 29k?

My CTS reads 29k when I unhook them and the motor knocks like crazy. No fuel comes out of the barb where the race plug is even at 29k. I don't have a hose on it. The thing that is weird is it don't gradually fall. It just goes from like 24k to 7500 in a instant

 

[Harbin_22]

Do you for sure have good supply pressure? Not be too nosie, but how much PW are you running?

 

[Ne-max]

Never dropped below 8psi. Running a fuel lab 200. Not sure on pulse. It does it in all the tunes

 

[Ne-max]

If anyone is willing to look I have data logs

 

[CaptPhil]

Can you feel a drastic drop in power when you were at the track? The truck would sputter and be very smokey if rail was dropping that low.

Sent from my SM-G900V using Tapatalk

 

[juddski88]

I would take the 2nd cp3 controller out of the equation and see what happens.

 

[Ne-max]

I would take the 2nd cp3 controller out of the equation and see what happens.

Controller or the whole set up? Just run the valley one?

 

[Ne-max]

Can you feel a drastic drop in power when you were at the track? The truck would sputter and be very smokey if rail was dropping that low.

Sent from my SM-G900V using Tapatalk

Ya. It launched great at 23000ish psi. Then dropped rail and doggish the rest of the track. Ran a 8.21 at 88mph