PDA

View Full Version : Fuel system question

New2me87GN
10-04-2006, 03:37 PM
On my 87 GN the prevous owner installed 2 fuel fumps (outside the tank) and did away with the 1 in the tank (not sure on his reasoning). He added another 3/8 line through the sending unit into the tank and the car now has 2 fuel lines going from the tank. Each fuel pump is hooked to a seperate line and after some tracing of the lines I found out that each fuel line is plumbed to each side of the fuel rail (seperate pump for each side). 1 pump is wired to the stock power source and the other pump gets power from a wire that I haven't found the other end of yet , but if they both are running the car dies.
Now this car has been sitting for the last 12 years and it had a full tank of stale gas and I finally got everything cleaned up and new gas and new filters installed. My questions are why 2 pumps ran like they are and where do I check to see why the stock fuel pump power wire dosn't have power (I already checked the fuse)
XSboost
10-31-2006, 04:25 PM
check the fuel pump relay on the passenger side of the fender.
Does the car need this set up? if not put it all back to stock
with a good intank pump and a hot wire kit should and will take most
GN in to the mid 11s with out a problem.
New2me87GN
11-04-2006, 08:11 PM
OK, I have it running on the 1 main pump. I believe the second pump is for when your at WOT. Now my new question is the 2nd pump usto work of a relay, but the relay wires wern't hooked under the dash, so how do I hook the wires up to make the 2nd pump kick on under WOT?
Keller
11-04-2006, 08:14 PM
with a good intank pump and a hot wire kit should and will take most GN in to the mid 11s with out a problem.
With a modern pump. Not with a 12-year old design pump!
Keller
11-04-2006, 08:16 PM
how do I hook the wires up to make the 2nd pump kick on under WOT?
There might have been a Hobbs switch wired to do this off of boost pressure. Maybe TPS voltage. It all depends...
IL KIM
11-04-2006, 08:40 PM
I used to have 2nd pump; a Kenne Bell pump that was installed outside the tank. It was powered off the same wire as the in-tank pump. One of your 2 outside the tank could be a booster pump? I got rid of mine this year and installed a modern Walbro in tank pump and hot wire kit. Did not need the booster pump with this set-up, and booster temps typically increase fuel temperature relative to an in-tank one.