Fuel Pressure problems
Thread Starter
Pro
Joined: Mar 2005
Posts: 511
Likes: 17
From: Coralville Ia
Fuel Pressure problems
Guys,
Have you had any problems with fuel pressure in your FI Vette? My tuner is working on my kit, and is running into a pressure problem at around 5500 rpm. By 6000 it's down to 30 lbs?
I have a 99 vette. Installed the A&A kit with the LPE pump, 3.8" pulley and 60 lbs injectors. My tuner said so far he's gotten 380 hp.
Do you have any ideas? Andy from A&A suggested that pressure is being bled off to the other tank, and didn't really have any suggestions on how to fix it. Have any of you seen this? Any fixes? I'm having my turner replace the fuel filter as a try at a simple fix. Andy said he would replace the pump, but didn't think that was the problem.
Any ideas?
Thanks,
Jesse
Have you had any problems with fuel pressure in your FI Vette? My tuner is working on my kit, and is running into a pressure problem at around 5500 rpm. By 6000 it's down to 30 lbs?
I have a 99 vette. Installed the A&A kit with the LPE pump, 3.8" pulley and 60 lbs injectors. My tuner said so far he's gotten 380 hp.Do you have any ideas? Andy from A&A suggested that pressure is being bled off to the other tank, and didn't really have any suggestions on how to fix it. Have any of you seen this? Any fixes? I'm having my turner replace the fuel filter as a try at a simple fix. Andy said he would replace the pump, but didn't think that was the problem.
Any ideas?
Thanks,
Jesse
Tech Contributor
Joined: Apr 2007
Posts: 10,924
Likes: 78
From: Forney Texas
Not much is adding up to me on this. The car should make 500rwhp without question. The fuel system should support that much power easily. I would expect you to start having trouble with fuel pressure at 550+rwhp.
I would recommend you reground the pump to the frame with a 10 gauge wire, the frame sanded down to shiny metal, using a well crimped ring terminal. Then tap the power wire at the pump and measure the voltage at WOT. I'll bet it's low. The easy, simple fix is to buy a Racetronix harness. The less expensive way out is to buy a good Tyco 30amp relay, fuse link, 2- ring terminals, 4 .250 spade terminals, and 10 feet of 10 gauge wire. Run a wire from the back of the alternator, through the rocker panel to the rear of the car where the fuel pump is. Crimp a .250 female spade terminal to the wire and push it down on pin 87 of the relay. Cut the power wire feeding the fuel pump and extend the wires. The side that goes to the pump will go to pin 30 of the relay. The side opposite the pump will go to pin 86. Ground pin 85. Best case scenario, you're probably getting 11.5v to the pump. With new, higher quality, close proximity ground and the direct wire to the highest voltage point in the vehicle, your voltage should pick up by 2. Percentage wise looks even better. After you replace the filter and try my little fix, run the car and we'll see what else needs changing.
I would recommend you reground the pump to the frame with a 10 gauge wire, the frame sanded down to shiny metal, using a well crimped ring terminal. Then tap the power wire at the pump and measure the voltage at WOT. I'll bet it's low. The easy, simple fix is to buy a Racetronix harness. The less expensive way out is to buy a good Tyco 30amp relay, fuse link, 2- ring terminals, 4 .250 spade terminals, and 10 feet of 10 gauge wire. Run a wire from the back of the alternator, through the rocker panel to the rear of the car where the fuel pump is. Crimp a .250 female spade terminal to the wire and push it down on pin 87 of the relay. Cut the power wire feeding the fuel pump and extend the wires. The side that goes to the pump will go to pin 30 of the relay. The side opposite the pump will go to pin 86. Ground pin 85. Best case scenario, you're probably getting 11.5v to the pump. With new, higher quality, close proximity ground and the direct wire to the highest voltage point in the vehicle, your voltage should pick up by 2. Percentage wise looks even better. After you replace the filter and try my little fix, run the car and we'll see what else needs changing.
Pro
Joined: Sep 2008
Posts: 660
Likes: 16
From: Tustin California
When Andy installed my supercharger on my 2000 coupe, he wasn't getting enough fuel pressure and/or flow. The Lingenfelter in tank pump that came with his kit was fine. He put in a new stock fuel filter/regulator and the problem was solved. That was 18 months ago and it still is perfect. Good luck! Rod
Thread Starter
Pro
Joined: Mar 2005
Posts: 511
Likes: 17
From: Coralville Ia
Thanks for your info. My tuner still has a VERY conservative tune, so I'm not to concerned with the HP at this point. That number is also uncorrected from a SuperFlow AutoDyn 30, and it was unusually hot today. Stock my car had 290 HP.
Given my EE background I was also concerned with the voltage drop based on others issues with the stock wiring. So, that is on the list for things to test tomorrow. If it's an issue I'll get the Racetronix harness. One thing that makes this some what easier is that I already have an 8 gauge wire run to the rear for my stereo. So, for testing voltage drop it would not be hard to wire in a relay and test this.
Thanks,
Jesse
Given my EE background I was also concerned with the voltage drop based on others issues with the stock wiring. So, that is on the list for things to test tomorrow. If it's an issue I'll get the Racetronix harness. One thing that makes this some what easier is that I already have an 8 gauge wire run to the rear for my stereo. So, for testing voltage drop it would not be hard to wire in a relay and test this.
Thanks,
Jesse
Not much is adding up to me on this. The car should make 500rwhp without question. The fuel system should support that much power easily. I would expect you to start having trouble with fuel pressure at 550+rwhp.
I would recommend you reground the pump to the frame with a 10 gauge wire, the frame sanded down to shiny metal, using a well crimped ring terminal. Then tap the power wire at the pump and measure the voltage at WOT. I'll bet it's low. The easy, simple fix is to buy a Racetronix harness. The less expensive way out is to buy a good Tyco 30amp relay, fuse link, 2- ring terminals, 4 .250 spade terminals, and 10 feet of 10 gauge wire. Run a wire from the back of the alternator, through the rocker panel to the rear of the car where the fuel pump is. Crimp a .250 female spade terminal to the wire and push it down on pin 87 of the relay. Cut the power wire feeding the fuel pump and extend the wires. The side that goes to the pump will go to pin 30 of the relay. The side opposite the pump will go to pin 86. Ground pin 85. Best case scenario, you're probably getting 11.5v to the pump. With new, higher quality, close proximity ground and the direct wire to the highest voltage point in the vehicle, your voltage should pick up by 2. Percentage wise looks even better. After you replace the filter and try my little fix, run the car and we'll see what else needs changing.
I would recommend you reground the pump to the frame with a 10 gauge wire, the frame sanded down to shiny metal, using a well crimped ring terminal. Then tap the power wire at the pump and measure the voltage at WOT. I'll bet it's low. The easy, simple fix is to buy a Racetronix harness. The less expensive way out is to buy a good Tyco 30amp relay, fuse link, 2- ring terminals, 4 .250 spade terminals, and 10 feet of 10 gauge wire. Run a wire from the back of the alternator, through the rocker panel to the rear of the car where the fuel pump is. Crimp a .250 female spade terminal to the wire and push it down on pin 87 of the relay. Cut the power wire feeding the fuel pump and extend the wires. The side that goes to the pump will go to pin 30 of the relay. The side opposite the pump will go to pin 86. Ground pin 85. Best case scenario, you're probably getting 11.5v to the pump. With new, higher quality, close proximity ground and the direct wire to the highest voltage point in the vehicle, your voltage should pick up by 2. Percentage wise looks even better. After you replace the filter and try my little fix, run the car and we'll see what else needs changing.
Thread Starter
Pro
Joined: Mar 2005
Posts: 511
Likes: 17
From: Coralville Ia
Thanks for the help guys. Seems it was the filter/regulator! Don't have new HP numbers yet. 
Thanks for your info. My tuner still has a VERY conservative tune, so I'm not to concerned with the HP at this point. That number is also uncorrected from a SuperFlow AutoDyn 30, and it was unusually hot today. Stock my car had 290 HP.
Given my EE background I was also concerned with the voltage drop based on others issues with the stock wiring. So, that is on the list for things to test tomorrow. If it's an issue I'll get the Racetronix harness. One thing that makes this some what easier is that I already have an 8 gauge wire run to the rear for my stereo. So, for testing voltage drop it would not be hard to wire in a relay and test this.
Thanks,
Jesse
Given my EE background I was also concerned with the voltage drop based on others issues with the stock wiring. So, that is on the list for things to test tomorrow. If it's an issue I'll get the Racetronix harness. One thing that makes this some what easier is that I already have an 8 gauge wire run to the rear for my stereo. So, for testing voltage drop it would not be hard to wire in a relay and test this.
Thanks,
Jesse
Former Vendor
Joined: Jul 2008
Posts: 4,327
Likes: 7
From: Oxnard SoCal www.aacorvette.com www.superchargersuperstore.com
When Andy installed my supercharger on my 2000 coupe, he wasn't getting enough fuel pressure and/or flow. The Lingenfelter in tank pump that came with his kit was fine. He put in a new stock fuel filter/regulator and the problem was solved. That was 18 months ago and it still is perfect. Good luck! Rod
Le Mans Master
Joined: Oct 2005
Posts: 7,088
Likes: 1,829
From: Metro Detroit Michigan
Guys,
Have you had any problems with fuel pressure in your FI Vette? My tuner is working on my kit, and is running into a pressure problem at around 5500 rpm. By 6000 it's down to 30 lbs? I have a 99 vette. Installed the A&A kit with the LPE pump, 3.8" pulley and 60 lbs injectors. My tuner said so far he's gotten 380 hp.
Have you had any problems with fuel pressure in your FI Vette? My tuner is working on my kit, and is running into a pressure problem at around 5500 rpm. By 6000 it's down to 30 lbs?
I have a 99 vette. Installed the A&A kit with the LPE pump, 3.8" pulley and 60 lbs injectors. My tuner said so far he's gotten 380 hp.
Thread Starter
Pro
Joined: Mar 2005
Posts: 511
Likes: 17
From: Coralville Ia
I'm not sure, but the regulator/filter fixed it... the fuel pressure is now much more steady, the pressure was dropping to 30PSI at 6000 rpm. Now it's at 55! So problem solved.
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Thread Starter
Pro
Joined: Mar 2005
Posts: 511
Likes: 17
From: Coralville Ia
I will post a full message with pics, and track numbers in a couple weeks. But since you asked. Baseline was 290HP. With a 3.8" pulley, V3-si, and a conservative tune (Min 11.9 AFR) it produced 455.9 RWHP, 433.8 RWTRQ. I've only done runs up to 60mph, but above 20mph it pulls like no other! VERY FUN!! The police are out in force, so I did not want to press my luck! 
