Fuel Pump Circuit Problem
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Joined: Oct 2001
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From: Santa Monica, Ca, USA
Car: Red 05 Viper SRT 10 & Yellow 03 Z06
Engine: 87 Camaro - 355 TPI Custom
Transmission: 5 Speed BW World Class
Axle/Gears: 3.73:1
Fuel Pump Circuit Problem
All questions pertain to a 1988 TPI 350 with a Mass Air ECM.
Question 1: What other relays, if any, besides the Fuel Pump relay, are involved in the fuel pump circuit when you turn the key on?
Question 2: What is the under dash, Fuel Pump fuse rating supposed to be - 20A, 25A,or what?
Question 3: Can old wiring in the FP circuit cause the resistance to go up, thereby requiring more amperage to trigger the FP when the ignition is placed in the on position?
Question 4: If the answer to question 3 is yes, then how can that be fixed?
Question 5: This one's for those of you who really know your stuff - what does it mean when you jump terminals A & E (1st and last) on the FP relay harness, while using a 20A fused jumper wire, and the FP doesn't come on until you tap the terminals together (using the jumper wire) several times?
Question 6: Would it be advisable to bypass the FP relay by installing a toggle switch between terminals A and E and placing it on my dash - switching it on when I want to start the car and off when i turn it off?
Here's some info that might help you in answering the questions above:
*Its a brand new FP relay;
*when I put the key in the on position, I hear a click in either the Mass Air Flow relay, or the Mass Air Flow Burn-Off relay;
*the ECM does activate the FP relay for 2 seconds when the ignition is placed in the on position;
*there are no codes set;
*the FP is a high flow Holley in-tank repalcement;
*when I drive the car, after it finally starts, it seems to run fine and has power;
*all of the circuits are connected and seem to be working fine; and
*when the car is running, I disconnected the FP relay and it still continued to run so I know that the oil pressure switch is not involved in this problem.
Whoever can figure this one out is the all time guru of TPIs as far as I'm concerned
Question 1: What other relays, if any, besides the Fuel Pump relay, are involved in the fuel pump circuit when you turn the key on?
Question 2: What is the under dash, Fuel Pump fuse rating supposed to be - 20A, 25A,or what?
Question 3: Can old wiring in the FP circuit cause the resistance to go up, thereby requiring more amperage to trigger the FP when the ignition is placed in the on position?
Question 4: If the answer to question 3 is yes, then how can that be fixed?
Question 5: This one's for those of you who really know your stuff - what does it mean when you jump terminals A & E (1st and last) on the FP relay harness, while using a 20A fused jumper wire, and the FP doesn't come on until you tap the terminals together (using the jumper wire) several times?
Question 6: Would it be advisable to bypass the FP relay by installing a toggle switch between terminals A and E and placing it on my dash - switching it on when I want to start the car and off when i turn it off?
Here's some info that might help you in answering the questions above:
*Its a brand new FP relay;
*when I put the key in the on position, I hear a click in either the Mass Air Flow relay, or the Mass Air Flow Burn-Off relay;
*the ECM does activate the FP relay for 2 seconds when the ignition is placed in the on position;
*there are no codes set;
*the FP is a high flow Holley in-tank repalcement;
*when I drive the car, after it finally starts, it seems to run fine and has power;
*all of the circuits are connected and seem to be working fine; and
*when the car is running, I disconnected the FP relay and it still continued to run so I know that the oil pressure switch is not involved in this problem.
Whoever can figure this one out is the all time guru of TPIs as far as I'm concerned
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92camaroJoe
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Aug 13, 2015 06:07 AM




