fuel pump voltage at idle
04-06-15, 06:29 PM
#1
fuel pump voltage at idle
What should the voltage at the fuel pump read while at idle? The car seems to be running rich at idle. Slight arrhythmic bog and a light fuel vapor haze from the exhaust. It has gotten better the more tuning and parts I replace, but it seems to just be masking a fuel system problem.
I read about 2 step relays that are supposed to cut voltage to the fuel pump at idle to around 9v. Could this be it? I havent checked voltage at the pump yet...
I have the stock fuel pump + coming from the 1980 emissions computer feeding 12v to the circuit opening relay (BW wire) triggered by the Br AFM wire and thick BR connected to the ignition START wire feeding 12v through the L wire going to where the stock fuel pump wire was cut and re routed (to the circuit opening relay). Should the circuit opening relay not perform the function of cutting voltage? Or is there a second relay somewhere I dont have?
The car has no neutral switch. Could this cause a rich mixture? I know on a s5 if it is unplugged the engine will idle a bit rough because it doesnt know if it is in gear or not.
Surely the Airtex E8000 pump is not too much for this car right? Ive heard of several people using it. Stock FPR regulates to about 40-50 PSI correct? Stock pump puts out about 40 PSI. So will a 70-95 PSI pump over work the stock FPR?
Specs are ...
30 GPH
70-95 PSI
Ill be buying some new injectors soon so maybe thats the issue. Just a drippy injector.
I read about 2 step relays that are supposed to cut voltage to the fuel pump at idle to around 9v. Could this be it? I havent checked voltage at the pump yet...
I have the stock fuel pump + coming from the 1980 emissions computer feeding 12v to the circuit opening relay (BW wire) triggered by the Br AFM wire and thick BR connected to the ignition START wire feeding 12v through the L wire going to where the stock fuel pump wire was cut and re routed (to the circuit opening relay). Should the circuit opening relay not perform the function of cutting voltage? Or is there a second relay somewhere I dont have?
The car has no neutral switch. Could this cause a rich mixture? I know on a s5 if it is unplugged the engine will idle a bit rough because it doesnt know if it is in gear or not.
Surely the Airtex E8000 pump is not too much for this car right? Ive heard of several people using it. Stock FPR regulates to about 40-50 PSI correct? Stock pump puts out about 40 PSI. So will a 70-95 PSI pump over work the stock FPR?
Specs are ...
30 GPH
70-95 PSI
Ill be buying some new injectors soon so maybe thats the issue. Just a drippy injector.
Last edited by NCross; 04-06-15 at 06:35 PM.
04-07-15, 03:21 PM
#2
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the GSL-SE just runs 12v at the pump all the time, the FC first adopted the two speed fuel pump.
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