Fuel drainback problem
Thread Starter
Instructor
Joined: Jun 2005
Posts: 109
Likes: 0
From: New Milford Ct
Fuel drainback problem
I recently dumped the cross-fire in my '84 in favor of the more performance friendly TPI. I changed the pump over to the '85 spec, using GM parts. Now, the fuel drains back causing very long start times. I was told by a GM technician that the fuel pump has a check valve in it, which most likely went bad. It was a new part, so I returned it for another one, same problem. Any ideas as to what it could be, or if the check valve is actually in the pump?
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
People have been putting '85 fuel pumps into '84's for years with no problems. Exactly what did you do? Swap intake systems? I think you are about to be seriously disappointed. There are three causes for the fuel system to bleed off pressure. One is the fuel pump, which you have checked out thoroughly and the other two are the fuel pressure regulator and the fuel injectors.
RACE ON!!!
RACE ON!!!
Thread Starter
Instructor
Joined: Jun 2005
Posts: 109
Likes: 0
From: New Milford Ct
I put a whole new engine in this. I managed to get my hands on a wrecked, and I mean wrecked, '85. This car was totaled from seats back! Practically nothing there! I took the intake set-up, computer, and every wiring harness out of the wrecked '85 and put it on the new engine. I replaced the regulator, injectors, and throttle body with brand new pieces. The throttle body and injectors were GM parts, while the regulator was an adjustable unit from Speed and Performance. From what I've read about these adjustable units, I'd imagine that's where my problem is most likely to be. Guess I'll put the original one out of the '85 in and see what happens.
Thanks a million guys!
Thanks a million guys!
