Low Fuel Pressure??
Thread Starter
Intermediate
Joined: Sep 2005
Posts: 25
Likes: 0
Low Fuel Pressure??
After washing the car and vacuuming under the hood, the car starts fine, but not able to accelerate, and get some backfire through the intake. I had a friend help me check for spark, injector signal and for vacuum leaks. We next put a pressure gage on the fuel system and the reading was 28 LBS (under the 34-39 range). Best guess at this point in fuel filter, fuel regulator or fuel pump, or some combination as best we can tell. I change the fuel filter today and no change. Looking for any advice. Was thinking fuel pump next, car has 149,000 and it may be time. OPen to any ideas, weather is getting too nice for the car to be idle. - Thanks - Harry G
Race Director
Joined: Feb 2004
Posts: 12,518
Likes: 19
After washing the car and vacuuming under the hood, the car starts fine, but not able to accelerate, and get some backfire through the intake. I had a friend help me check for spark, injector signal and for vacuum leaks. We next put a pressure gage on the fuel system and the reading was 28 LBS (under the 34-39 range). Best guess at this point in fuel filter, fuel regulator or fuel pump, or some combination as best we can tell. I change the fuel filter today and no change. Looking for any advice. Was thinking fuel pump next, car has 149,000 and it may be time. OPen to any ideas, weather is getting too nice for the car to be idle. - Thanks - Harry G
Team Owner
Joined: Jul 2004
Posts: 28,462
Likes: 3,288
From: Hartford WI
First things first. Change the fuel filter. If that doesn't cure it, you are looking at a new fuel pump. Not much work on that one since you don't have to drop the tank.
http://www.racetronix.com/RX-C4469-FPKG-2.html
http://www.racetronix.com/RX-C4469-FPKG-2.html
Team Owner
Joined: Jul 2004
Posts: 28,462
Likes: 3,288
From: Hartford WI
Safety Car
Joined: Sep 2001
Posts: 4,157
Likes: 554
From: Glenbeulah Wi
28 lbs is lower pressure then the regulator should be set at. To see if it is a regulator problem or a pump problem disconnect the vacuum line at the regulator when the car is running and see if the pressure jumps up 4 or 5 pounds. If the pressure spikes up (and stays up with the hose disconnected) the problem is the regulator and not the pump. I would hate to see you replace the pump and still have the problem.
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Thread Starter
Intermediate
Joined: Sep 2005
Posts: 25
Likes: 0
Went to Harbor Freight and got a gage, it leaked so I used teflon tape and got it to work without flutter or a leak, was close to 34 pounds. Removed the vacuum line and it only jump about 2 pounds and did not stay up, so it does not look like the regulator. Was still able to rev and periodically get the loss of power and the backfire through the throttle body. When I reved it, the pressure did drop. when I shut it down the pressure creeped up to 40. Looks like it may be pump replacement time unless someone has another Idea. I am guessing could be the sending unit on the pump or something with the screen?, but I guess I can see that when I pull the pump.
Is there any pump that I should stay away from. Local parts store had delphi, airtex, one place carried Bosch. Will be looking to purchase the pump, strainer, and harness.
Is there any pump that I should stay away from. Local parts store had delphi, airtex, one place carried Bosch. Will be looking to purchase the pump, strainer, and harness.
Last edited by Harry G; Apr 4, 2009 at 03:31 PM.