86 tuned port - no power to fuel pump
09-09-2015, 09:59 PM
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86 tuned port - no power to fuel pump
Hi this is my first post
I have 86 iroc with tuned port, setting up for a while, cranks but no start. no power to fuel pump, inline 20a near battery is good, replaced fuel pump relay near brake booster, fuel rail reads 0 psi when cranking over but I get about 30 psi on oil pressure gauge, test terminal (B) adld reads 5v, test terminal for fuel pump (G) sends varies readings on multimeter - OL..OL..OL, like meter cant tell what voltage, I know its supposed to be 2-5v, but all I get is sporadic reading. When I short B terminal to ground, fan goes on and I get service code "12", no other codes. Any idea what else to check, not sure how to check fuel pump switch (oil pressure sender) or ECM for voltages. Any help will be greatly appreciated.
I have 86 iroc with tuned port, setting up for a while, cranks but no start. no power to fuel pump, inline 20a near battery is good, replaced fuel pump relay near brake booster, fuel rail reads 0 psi when cranking over but I get about 30 psi on oil pressure gauge, test terminal (B) adld reads 5v, test terminal for fuel pump (G) sends varies readings on multimeter - OL..OL..OL, like meter cant tell what voltage, I know its supposed to be 2-5v, but all I get is sporadic reading. When I short B terminal to ground, fan goes on and I get service code "12", no other codes. Any idea what else to check, not sure how to check fuel pump switch (oil pressure sender) or ECM for voltages. Any help will be greatly appreciated.
09-10-2015, 07:12 AM
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Re: 86 tuned port - no power to fuel pump
Hi this is my first post
I have 86 iroc with tuned port, setting up for a while, cranks but no start. no power to fuel pump, inline 20a near battery is good, replaced fuel pump relay near brake booster, fuel rail reads 0 psi when cranking over but I get about 30 psi on oil pressure gauge, test terminal (B) adld reads 5v, test terminal for fuel pump (G) sends varies readings on multimeter - OL..OL..OL, like meter cant tell what voltage, I know its supposed to be 2-5v, but all I get is sporadic reading. When I short B terminal to ground, fan goes on and I get service code "12", no other codes. Any idea what else to check, not sure how to check fuel pump switch (oil pressure sender) or ECM for voltages. Any help will be greatly appreciated.
I have 86 iroc with tuned port, setting up for a while, cranks but no start. no power to fuel pump, inline 20a near battery is good, replaced fuel pump relay near brake booster, fuel rail reads 0 psi when cranking over but I get about 30 psi on oil pressure gauge, test terminal (B) adld reads 5v, test terminal for fuel pump (G) sends varies readings on multimeter - OL..OL..OL, like meter cant tell what voltage, I know its supposed to be 2-5v, but all I get is sporadic reading. When I short B terminal to ground, fan goes on and I get service code "12", no other codes. Any idea what else to check, not sure how to check fuel pump switch (oil pressure sender) or ECM for voltages. Any help will be greatly appreciated.
Locate the fuel pump connector at the back and test for 12 volts when cranking (light blue wire). If 12 volts present, most likely the fuel pump is toasted. If 12 volts not present then you have to work backward. ECM activates fuel pump relay (dark green/white wire at relay). The fuel pump connector could be under the vehicle against the floor pan in the rear end area or under the carpet behind the back seat. I'm not familiar with 1986 model. The oil pressure switch sender is a back-up and does not control the fuel pump.
Best of luck!
09-14-2015, 04:16 PM
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Pump Slump
Using a voltmeter or test light (the type for testing for voltage, not a continuity tester) to see if you have power on pin A of the pump relay orange wire.
It doesn’t matter what position the key is in.
If you don’t have power there check the inline fuse located near the battery.
If there is power there jump pin A to pin E gray wire for a second or two with a piece of wire.
Does the pump run when you do that?
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The Next Time I’m In The Sand Trap, Let It Be Golf, Not My Car
It doesn’t matter what position the key is in.
If you don’t have power there check the inline fuse located near the battery.
If there is power there jump pin A to pin E gray wire for a second or two with a piece of wire.
Does the pump run when you do that?
◙◙◙◙◙◙◙◙◙◙◙◙◙◙◙
Happy Racing !
◙◙◙◙◙◙◙◙◙◙◙◙◙◙◙
The Next Time I’m In The Sand Trap, Let It Be Golf, Not My Car
09-20-2015, 01:43 PM
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Re: Pump Slump
Using a voltmeter or test light (the type for testing for voltage, not a continuity tester) to see if you have power on pin A of the pump relay orange wire.
It doesn’t matter what position the key is in.
If you don’t have power there check the inline fuse located near the battery.
If there is power there jump pin A to pin E gray wire for a second or two with a piece of wire.
Does the pump run when you do that?
◙◙◙◙◙◙◙◙◙◙◙◙◙◙◙
Happy Racing !
◙◙◙◙◙◙◙◙◙◙◙◙◙◙◙
Happy Racing !
◙◙◙◙◙◙◙◙◙◙◙◙◙◙◙
The Next Time I’m In The Sand Trap, Let It Be Golf, Not My Car
09-20-2015, 01:44 PM
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Re: 86 tuned port - no power to fuel pump
Large gauge orange wire at relay (A) has voltage, when I jump to relay (E) all I hear is clicking from relay, I disconnected the 3 wire connector at the fuel pump, tried jumping the relay (A&E pins) and checking for voltage at the 3 pins and no voltage, doesn't look like power going to the fuel pump connector, maybe ecm issue or maybe an issue with a chewed wire ( I always worry about mice), any more troubleshooting tips would be appreciated
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09-20-2015, 01:48 PM
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Re: Pump Slump
Large gauge orange wire at relay (A) has voltage, when I jump to relay (E) all I hear is clicking from relay, I disconnected the 3 wire connector at the fuel pump, tried jumping the relay (A&E pins) and checking for voltage at the 3 pins and no voltage, doesn't look like power going to the fuel pump connector, maybe ecm issue or maybe an issue with a chewed wire ( I always worry about mice), any more troubleshooting tips would be appreciated
**should note the relay clicking was after I disconnected fuel pump connector at rear near gas tank, when this connector was hooked up the relay just made one click sound but still no fuel pump sound
09-20-2015, 05:09 PM
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Re: Pump Slump
Plug the fuel pump and engage the relay. Check voltage reading on orange wire and on light blue. Make sure when you check that your voltmeter ground is at the battery. Sounds like maybe a drop in voltage when pump engages thus pump toasted or could also be a bad ground.
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