Hi side fuel pressure problem
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Heel & Toe
Joined: Dec 2016
Posts: 15
Likes: 0
Hi side fuel pressure problem
Okay guys we need some help. I have my 14 Stingray the shop right now. We have put lt4 injectors in along with a brand new lt4 pump. It is making good pressure on the low side but only making around 70 to 80 on the high side at idle. We tried another brand new lt4 pump and getting the same reading. It has plenty of clearance with the lash cap, preload was set correctly. We went back to the LT1 pump and getting in the 1100 range at idle. Why am I not in the 1100 with the new lt4 pump?
8th Gear
Joined: Jun 2020
Posts: 8
Likes: 2
From: St Paul
Just went thru this same issue, Change the fuel inlet line from back to pump with a LT4 line. (https://paceperformance.com/i-201648...pump-pipe.html)
See my posts........ This solved it!
I will try to simplify.
Spent a year researching on what we want to do, bought everything and started the build. (2014 C7 LT1 Wet Sump 7 Speed Manual, 2862 original miles)
1) Procharger P1 kit set up at 9 PSI
2) Procharger Intake
3) Texas Speed EL-C7 Camshaft 32% Lobe, DOD, VVT Lock and Valve Train Upgrades
4) GM LT4 HPFP and LT4 Injectors
5) Stainless Works 2 in long tube headers and 3 X Pipe with NO cats
6) DSX E85 kit
7) GPI Drop in piston and rod kit, stock bore compression 10.5 to 1
8) Alky Control Meth Kit Twin 15 nozzle
9) DSX IAT / BARO Breakout Kit
10) Stock Throttle Body custom ported by Tony Momo Engines
11) Kaizin Trans Cage
12) Monster Triple Disc
13) Stock Lift Pump
So here is what I know. Built the car, made sure it started ran it and bleed the cooling system. CEL came on codes were for O2 sensors. Had car towed to the tuner. 6 Hours later he calls and says come and get pick it up. It will not run there is no fuel pressure. We have it towed back to our shop pull codes and there is no a HP tune in it and we have codes for low fuel pressure and the car is reduced power mode. So we do some research and try a new LT4 pump ( cam is a 32% lobe and preload is correct) Run the car and we get the same issue. But this time with the laptop hooked up it starts right up, pressure drops to 38 -80 lbs. Shut the car off the pressure climbs tp 1800-2100 and stays until it is started again. Stumped. Do some research again and find that the Katech front cover vvt delete kit is a fail. the cam gear is not right and sets the timing 6-8 degrees retarded. Katech admitted this so we took all that off and put a brand new VVT cam gear from GM and used the lock out from TS and put it back together. Started it and Same issue! We also changed the rail sensor just in case because there is a GM recall on them and it was cheap to do. We thought the cam issue would solve it as the pump make the pressure but the solenoid is what releases it and that is controlled by the cam sensor and now that it is back to stock location it did not change. We also installed a NEW GM computer just incase the tuner bricked it. Runs the same. Loaded a stock ZO6 file, the same issues.
Anyone have any ideas? Any Help would be greatly appreciated,
Thank You For Your Time.
See my posts........ This solved it!
I will try to simplify.
Spent a year researching on what we want to do, bought everything and started the build. (2014 C7 LT1 Wet Sump 7 Speed Manual, 2862 original miles)
1) Procharger P1 kit set up at 9 PSI
2) Procharger Intake
3) Texas Speed EL-C7 Camshaft 32% Lobe, DOD, VVT Lock and Valve Train Upgrades
4) GM LT4 HPFP and LT4 Injectors
5) Stainless Works 2 in long tube headers and 3 X Pipe with NO cats
6) DSX E85 kit
7) GPI Drop in piston and rod kit, stock bore compression 10.5 to 1
8) Alky Control Meth Kit Twin 15 nozzle
9) DSX IAT / BARO Breakout Kit
10) Stock Throttle Body custom ported by Tony Momo Engines
11) Kaizin Trans Cage
12) Monster Triple Disc
13) Stock Lift Pump
So here is what I know. Built the car, made sure it started ran it and bleed the cooling system. CEL came on codes were for O2 sensors. Had car towed to the tuner. 6 Hours later he calls and says come and get pick it up. It will not run there is no fuel pressure. We have it towed back to our shop pull codes and there is no a HP tune in it and we have codes for low fuel pressure and the car is reduced power mode. So we do some research and try a new LT4 pump ( cam is a 32% lobe and preload is correct) Run the car and we get the same issue. But this time with the laptop hooked up it starts right up, pressure drops to 38 -80 lbs. Shut the car off the pressure climbs tp 1800-2100 and stays until it is started again. Stumped. Do some research again and find that the Katech front cover vvt delete kit is a fail. the cam gear is not right and sets the timing 6-8 degrees retarded. Katech admitted this so we took all that off and put a brand new VVT cam gear from GM and used the lock out from TS and put it back together. Started it and Same issue! We also changed the rail sensor just in case because there is a GM recall on them and it was cheap to do. We thought the cam issue would solve it as the pump make the pressure but the solenoid is what releases it and that is controlled by the cam sensor and now that it is back to stock location it did not change. We also installed a NEW GM computer just incase the tuner bricked it. Runs the same. Loaded a stock ZO6 file, the same issues.
Anyone have any ideas? Any Help would be greatly appreciated,
Thank You For Your Time.
Last edited by jgouette; Jul 17, 2020 at 11:53 AM. Reason: More info
