fuel pressure lnf
#1
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fuel pressure lnf
I have a 2008 lnf with just bolt ons stock fuel system.
im on full e with a tune but i keep losin fuel pressure even when i was on e47 it would sputter at a high rpm and now at a high rpm it just falls on its face and sends me the code along with reduce engine power. Idk where to start besides with the HPFP but don’t want to throw my money away any ideas?
im on full e with a tune but i keep losin fuel pressure even when i was on e47 it would sputter at a high rpm and now at a high rpm it just falls on its face and sends me the code along with reduce engine power. Idk where to start besides with the HPFP but don’t want to throw my money away any ideas?
#2
I have a 2008 lnf with just bolt ons stock fuel system.
im on full e with a tune but i keep losin fuel pressure even when i was on e47 it would sputter at a high rpm and now at a high rpm it just falls on its face and sends me the code along with reduce engine power. Idk where to start besides with the HPFP but don’t want to throw my money away any ideas?
im on full e with a tune but i keep losin fuel pressure even when i was on e47 it would sputter at a high rpm and now at a high rpm it just falls on its face and sends me the code along with reduce engine power. Idk where to start besides with the HPFP but don’t want to throw my money away any ideas?
As running ethanol requires significantly richer A/F ratio, you're either running out of fuel on the low side (FP to the HPFP) or you've exceeded the capability of the HPFP/injectors. Start by monitoring the low side fuel pressure when the concern occurs; this can be done by installing a fuel pressure gauge at the shrader valve (if equipped), installing the fuel pressure gauge in-line (T-fitting), or monitoring the low side fuel pressure using a scan tool (if equipped with a low side sensor). If the fuel pressure drops when the concern occurs, you're starving the HPFP for fuel. In that case you'd need to upgrade your in-tank pump or install a booster pump.
If the low side fuel pressure isn't dropping, you'll need to monitor the FRP (fuel rail pressure) using a scan tool. If the FRP PID drops down and doesn't match the FRP desired PID when the concern occurs, you'll need to upgrade the HPFP/injectors to handle the extra fuel volume that is required for your setup.
#3
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To run full E you need upgraded injectors or fuel lobe or upgraded hpfp. there's people who will know exactly what you need for what you want to do (injectors & hpfp are easier to install than cams). But there's no way in hell you're running full E on stock fuel system. Highly advise against it.
#4
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Yeah running full e at sea level is not gonna happen without injectors or zzps fuel pump even then depending on what turbo and how its tuned who knows.
Pull the code and report back, but likely you're running out of fuel.
Pull the code and report back, but likely you're running out of fuel.
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#7
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You're running out of fuel pressure, the injectors are staying open to long and th hpfp cannot keep up. You need to either upgrade your fuel system (injectors and fuel pump) or go back to e47 and dial it back a touch. Running out of fuel at WOT is how things go boom really fast.
#8
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What ECaulk said is perfectly right. Whoever tuned you, I hope, would know how to get to full E safely. There's options that exist that haven't in the past (upgraded HPFP) so Opels/cam may be unnecessary. Now if it were me, I'd be doing Opels and HPFP upgrade just to make damn sure there's enough fuel. If you're big turbo you might need to look into upgraded cams but I think (from my limited knowledge & experience) that Opels & ZZP pump should be suitable for K04.
#9
Senior Member
The only way safely you can run full E stock on a k04 is at altitude. Opels actually hurt the FP when not running a lobe or upgraded HPFP. I prefer to run stock injectors on the lobe big turbo around 475hp because it'll have a higher FP. With Opels and a LT1 pump you can run E into the low 500s
#10
Low Side Fuel Pressure
I am hoping someone here can help me out. I posted on facebook groups without much help.
I have a 08 LNF 97k miles, only real "mods" was the 3 bar MAP and catted ZZP downpipe. It does have the Powell separator as well.
ZZP tuned it with HPT a few times now. When I first got this car it had a lot of codes I had been chasing down. I finally got them all resolved except my fuel trim was showing rich and setting off the MAF code. ZZP fixed the fuel trim with a tune and the MAF code went away, but then I started having cold start issues this first winter I had the car. It would stall out a few times before going back to normal (RPM dropping). I contacted ZZP and he turned the cat warm up back on, so it doesn't stall. Except now on a cold start it is misfiring on all cylinders (threw the misfire code for each cylinder plus the random misfire code). It seems to run fine after the cat warm up.
Doing some research I decided to test the low side fuel pressure, and I can't tell what I am looking at. It bounces all over the place. Can anyone help me out and tell me if it is reading normal? I created a youtube channel just so I can upload this.
On a side note, with the engine warm, key on and engine off, the fuel pressure was at 50 and slowly dropped to 30 over 10 minutes or so. I do appreciate any advice no matter how stupid I feel posting this.
I have a 08 LNF 97k miles, only real "mods" was the 3 bar MAP and catted ZZP downpipe. It does have the Powell separator as well.
ZZP tuned it with HPT a few times now. When I first got this car it had a lot of codes I had been chasing down. I finally got them all resolved except my fuel trim was showing rich and setting off the MAF code. ZZP fixed the fuel trim with a tune and the MAF code went away, but then I started having cold start issues this first winter I had the car. It would stall out a few times before going back to normal (RPM dropping). I contacted ZZP and he turned the cat warm up back on, so it doesn't stall. Except now on a cold start it is misfiring on all cylinders (threw the misfire code for each cylinder plus the random misfire code). It seems to run fine after the cat warm up.
Doing some research I decided to test the low side fuel pressure, and I can't tell what I am looking at. It bounces all over the place. Can anyone help me out and tell me if it is reading normal? I created a youtube channel just so I can upload this.
On a side note, with the engine warm, key on and engine off, the fuel pressure was at 50 and slowly dropped to 30 over 10 minutes or so. I do appreciate any advice no matter how stupid I feel posting this.
Last edited by sunnyvale; 04-25-2024 at 12:14 PM. Reason: To add the powell separator to the description of mods
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