New fuel sytem but pressure still drops, causes, cures?
07-29-2008, 08:15 PM
#1
Race Director
Thread Starter
New fuel sytem but pressure still drops, causes, cures?
I just went with the racetronix harness and pump kit and only a few thousand miles ago changed out the fuel filter. The car is a 2000 so the filter has the regulator on it 
Even after the fuel filter change the car made about 50 PSI pressure at idle and I could manually activate the boost-a-pump and squeeze 55. Now with the new setup it sits on 60 but WOT at any speed/gear results in an instant drop of about 5 PSI. I manually trigger the BAP now and it seems to have no effect at idle or otherwise. I am thinking the BAP was not wired in although the shop says it is, definately using the stock wiring to trigger the relay as when the BAP is unplugged the car won't start. Considering doing the 97-98 style return system but my car is only making 507 RWHP, my current setup should work fine I would think. The only thing I am concerned with is the car stops making power around 6k, TQ drops pretty hard but the AFR I guess is OK, tuner didn't say anything. Running the ECS blower cam so I thought it would pull hard until the end. When my car was on 4lbs of boost it pulled hard until redline... The instant drop in fuel pressure and the lack of power past 6k rpms has me worried, any input guys?
Even after the fuel filter change the car made about 50 PSI pressure at idle and I could manually activate the boost-a-pump and squeeze 55. Now with the new setup it sits on 60 but WOT at any speed/gear results in an instant drop of about 5 PSI. I manually trigger the BAP now and it seems to have no effect at idle or otherwise. I am thinking the BAP was not wired in although the shop says it is, definately using the stock wiring to trigger the relay as when the BAP is unplugged the car won't start. Considering doing the 97-98 style return system but my car is only making 507 RWHP, my current setup should work fine I would think. The only thing I am concerned with is the car stops making power around 6k, TQ drops pretty hard but the AFR I guess is OK, tuner didn't say anything. Running the ECS blower cam so I thought it would pull hard until the end. When my car was on 4lbs of boost it pulled hard until redline... The instant drop in fuel pressure and the lack of power past 6k rpms has me worried, any input guys?
07-30-2008, 01:23 PM
#2
Tech Contributor
Does the racetronix harness cover the pump ground as well? I would get the voltmeter and measure voltages at the pump and at the BAP. It would be a good thing if you could log the AFR's and all of the important parameters and see what's going on.
07-30-2008, 01:33 PM
#3
Tech Contributor
I just went with the racetronix harness and pump kit and only a few thousand miles ago changed out the fuel filter. The car is a 2000 so the filter has the regulator on it Even after the fuel filter change the car made about 50 PSI pressure at idle and I could manually activate the boost-a-pump and squeeze 55. Now with the new setup it sits on 60 but WOT at any speed/gear results in an instant drop of about 5 PSI. I manually trigger the BAP now and it seems to have no effect at idle or otherwise. I am thinking the BAP was not wired in although the shop says it is, definately using the stock wiring to trigger the relay as when the BAP is unplugged the car won't start. Considering doing the 97-98 style return system but my car is only making 507 RWHP, my current setup should work fine I would think. The only thing I am concerned with is the car stops making power around 6k, TQ drops pretty hard but the AFR I guess is OK, tuner didn't say anything. Running the ECS blower cam so I thought it would pull hard until the end. When my car was on 4lbs of boost it pulled hard until redline... The instant drop in fuel pressure and the lack of power past 6k rpms has me worried, any input guys?
Even after the fuel filter change the car made about 50 PSI pressure at idle and I could manually activate the boost-a-pump and squeeze 55. Now with the new setup it sits on 60 but WOT at any speed/gear results in an instant drop of about 5 PSI. I manually trigger the BAP now and it seems to have no effect at idle or otherwise. I am thinking the BAP was not wired in although the shop says it is, definately using the stock wiring to trigger the relay as when the BAP is unplugged the car won't start. Considering doing the 97-98 style return system but my car is only making 507 RWHP, my current setup should work fine I would think. The only thing I am concerned with is the car stops making power around 6k, TQ drops pretty hard but the AFR I guess is OK, tuner didn't say anything. Running the ECS blower cam so I thought it would pull hard until the end. When my car was on 4lbs of boost it pulled hard until redline... The instant drop in fuel pressure and the lack of power past 6k rpms has me worried, any input guys?
07-30-2008, 04:53 PM
#4
Race Director
Thread Starter
The BAP was previously installed in the car, and spliced into the wires by the battery box. I am thinking that they just added the racetronix harness and assuming the BAP (or forgetting) the BAP was already 'wired in', felt they didn't need to change anything.
07-30-2008, 05:09 PM
#5
Tech Contributor
The BAP was previously installed in the car, and spliced into the wires by the battery box. I am thinking that they just added the racetronix harness and assuming the BAP (or forgetting) the BAP was already 'wired in', felt they didn't need to change anything.
There is a provision in the racetronix harness for the BAP, why didn't they make use of that, and scrap the extra wiring? That way, you have one harness.
07-30-2008, 05:43 PM
#6
Safety Car
The bap, if wired before the harness was installed, powered the pump. After the harness is installed that power going to the pump becomes the trigger for the harness relay.
I would confirm with the shop that this is NOT how they've wired it in because if they did, it would explain why disconnecting the BAP keeps the system from running (no trigger).. that, and unless your wanting the additional voltage of the BAP to power the relay instead of the pump, it's very wrong.
I would confirm with the shop that this is NOT how they've wired it in because if they did, it would explain why disconnecting the BAP keeps the system from running (no trigger).. that, and unless your wanting the additional voltage of the BAP to power the relay instead of the pump, it's very wrong.
07-30-2008, 07:38 PM
#8
Race Director
Thread Starter
I asked them about it (the provision) but they said that where the BAP was would be OK.
07-30-2008, 07:43 PM
#9
Race Director
Thread Starter
The bap, if wired before the harness was installed, powered the pump. After the harness is installed that power going to the pump becomes the trigger for the harness relay.
I would confirm with the shop that this is NOT how they've wired it in because if they did, it would explain why disconnecting the BAP keeps the system from running (no trigger).. that, and unless your wanting the additional voltage of the BAP to power the relay instead of the pump, it's very wrong.
I would confirm with the shop that this is NOT how they've wired it in because if they did, it would explain why disconnecting the BAP keeps the system from running (no trigger).. that, and unless your wanting the additional voltage of the BAP to power the relay instead of the pump, it's very wrong.
