engergizing FP
Thread Starter
Racer
Joined: Sep 2002
Posts: 420
Likes: 1
From: SAN DIEGO CA
engergizing FP
Is there a way to engergize the FP by the ALDL (I think thats what it is located under the Steering wheel). I'm trying to test my new AFPR for leaks before I put the Superram back on.
Thread Starter
Racer
Joined: Sep 2002
Posts: 420
Likes: 1
From: SAN DIEGO CA
more problems.
Ok, i was able to energize the Fuel Pump to check for leaks. I found none. NOW...........when i try start the car with the key I dont hear the fuel pump wind up nor do I see any pressure on the fuel gauge. I get pressure when I energize through the "G" terminal. It goes up to 42 real nice. Then of course leaks down to 20psi in about 2 seconds. I checked the Fuse by the passenger side door and it looked good. Did I blow another fuse somewhere. Maybe a relay? How would I test a relay?
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Team Owner
Joined: Jan 2003
Posts: 20,254
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From: Summerland B.C. Canada
Melting Slicks
Joined: Feb 2002
Posts: 2,699
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From: The Black Hole LA
Very unlikely you blew a relay. But on my '90 there are 2 fuses and 2 relays. One relay is under the driver side dash. The key activates this one. The other is under the passenger side dash, the ecm activates this one. The 2nd fuse is on the auxilary fuse box (4 fuses) under the passenger side dash right behind the main fuse box.
The ecm will not send the signal (I think it grounds it) to the fuel pump relay if the air bag system is not in place (DERM module has to be hooked up). Of course this is only valid on '90 and later models.
The ecm will not send the signal (I think it grounds it) to the fuel pump relay if the air bag system is not in place (DERM module has to be hooked up). Of course this is only valid on '90 and later models.
Thread Starter
Racer
Joined: Sep 2002
Posts: 420
Likes: 1
From: SAN DIEGO CA
Is there more than on Relay or FP fuse on an 86 vette. I looked at he diagram and only saw one Relay and one blade fuse on the passenger side dash that controls the Fuel Pump. Of course, I could be mistaken.
Thread Starter
Racer
Joined: Sep 2002
Posts: 420
Likes: 1
From: SAN DIEGO CA
Tonight i will check the fuses and fuel relay. My question is what my next step should be if I replace the Fuel pump relay and Fuel pump fuse and make sure all the wires for the oil gauge in the back of the block are connected. Im just confused that the FP would pressure up if I connect it to the "g" terminal but not when I put the key in. Could this still be an indication of a bad FP. Thanks Agent the PDF's. Im sure this will come in handy tonight when im poking around.
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 32
From: The Top of Utah
Originally Posted by PMARTINEZ92126
Im just confused that the FP would pressure up if I connect it to the "g" terminal but not when I put the key in. Could this still be an indication of a bad FP. Thanks Agent the PDF's.
RACE ON!!!
Thread Starter
Racer
Joined: Sep 2002
Posts: 420
Likes: 1
From: SAN DIEGO CA
Ok i replaced both the blade fuse on the side of the dash and the fuel relay with a new one. I also checked the connections around the distributor because I changed out a cracked Distributor. All the wires look decent. I grounded the "G" terminal and it pressured up to 42 psi. I used the key and the Fuel gauge stays at zero. Can you think of anything else I might of missed. ECM blown, Another fuse somewhere? its an 86 automatic. 
Thread Starter
Racer
Joined: Sep 2002
Posts: 420
Likes: 1
From: SAN DIEGO CA
I just checked the PDF "Agent" sent me and it says to replace the Fuel Pump. After going through some diagnostics. The pump only runs after I apply 12 volts to it. The PDF says.........If the pump runs check for Plugged in line filter, plugged pump inlet filter, restricted fuel line, disconnected coupling hose or pulsator. Am I wrong to assume all this stuff is ok if the pump engergized with the 12 volts applied to the "g" terminal. This all started because I was not holding pressure in my fuel system. it would pressure up to 42 then it would leak down to 20psi in 2 seconds or so. I replace my AFPR with a new Holly one and I had all my injectors checked before i reinstalled them in my car a year ago. I also pulled them out of the manifold (still attached to the fuel rail) and they didnt leak at all after energizing the system for about 5 minutes using the 12 volt method. So all i can do is replace the pump......right 
Team Owner
Joined: Jan 2003
Posts: 20,254
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From: Summerland B.C. Canada
As stated before, the pump is working, why replace it. Did you pinch off fuel lines to see where the pressure loss is going ?
My fuel systems looses pressure fast too, causes me no grief so i don't worry about it. The check valve in tank may be your culprit also.
Is this causing starting problems ??
My fuel systems looses pressure fast too, causes me no grief so i don't worry about it. The check valve in tank may be your culprit also.
Is this causing starting problems ??
Thread Starter
Racer
Joined: Sep 2002
Posts: 420
Likes: 1
From: SAN DIEGO CA
Yes, the reason I was trying to find the pressure leak was because the car started extremely quick when cold but when it was hot.......forgot it. You would have to play with the accelerator pedal and hold it down for a minute while the car stumbled to a steady idle. It was very embarrassing. This has been a problem for awhile now. I changed out the injectors three times. First I took the boschs out and cleaned them and reinstalled them, then I replaced them with 24 pd Accels, and then after the tune shop wouldn't tune for Accels I bought 30 pd Fords from Jegs. Still same problem. So now I changed out the AFPR and double checked the injectors again. The only difference now is after I pinched the Return line and the Feed line and applied 12 battery volts to the "g" terminal I can't get the pressure to build using the key. Its at a 0 psi. I will need to do the Pinch test again because I had the return line and feed line confused. So thats my problem now. Car wont start even after replace the Fuel pump relay and the FP blade fuse. 
Race Director
Joined: Sep 2000
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From: The Top of Utah
Originally Posted by AGENT 86
As stated before, the pump is working, why replace it. Did you pinch off fuel lines to see where the pressure loss is going ?
My fuel systems looses pressure fast too, causes me no grief so i don't worry about it. The check valve in tank may be your culprit also.
Is this causing starting problems ??
My fuel systems looses pressure fast too, causes me no grief so i don't worry about it. The check valve in tank may be your culprit also.
Is this causing starting problems ??
You like throwing money at it don't you? You have needlessly replaced a fuel pump relay, without testing it, and now you want to replace a fuel pump that HAS been tested, and tests GOOD.
You have a problem in your fuel system wiring. The fuel pressure should jump up when you turn the key, even if only briefly, just like when you energize terminal "G" of the ALDL. You know it isn't the pump and it isn't the fuse. Now you need to trace, check wires and connections and TROUBLE SHOOT until you find the problem. That is, unless you can think of other GOOD parts that you'd like to replace.
There are three places that fuel pressure can dissipate through, without easy detection; the fuel pressure regulator, the injectors, and the fuel line check valve, in the fuel pump. It is relatively easy to isolate which of the three that may be the cause by pinching off fuel lines and observing what happens to the pressure. What have you learned?
RACE ON!!!