Fuel Pump Diagnostics |
|
Porsche, and the Porsche crest are registered trademarks of Dr. Ing. h.c. F. Porsche AG.
This site is not affiliated with Porsche in any way. Its only purpose is to provide an online forum for car enthusiasts. All other trademarks are property of their respective owners. |
|
Fuel Pump Diagnostics |
solex |
Mar 21 2010, 12:40 PM
Post
#1
|
Senior Member Group: Members Posts: 789 Joined: 12-January 05 From: Long Island, NY Member No.: 3,439 Region Association: North East States |
Hi All,
Need a little help to diagnose a fuel pump problem in a 75, I do not hear the pump when I turn the key to the run position. The car was running, I had a few occasions where it would not start, let it sit for a few days and it was start right up. The grounds: under the relay board, battery and transmission have all been cleaned. All fuses are good. The relay is working as I can hear it click into position. When the key is in the run position relay terminals 30 and 85 shows 12 volts. Terminal 86 show 0.03 volts and terminal 87 show zero volts. There is no voltage at either of the fuel pump terminals. The readings at the relay is counter to to what Haynes states (86 should read 12 and 85 should be ground). I not sure where to check next, really do not want to pull the tank. Any assistance would be appreciated. Thanks, Dan |
ClayPerrine |
May 16 2010, 09:52 PM
Post
#2
|
Life's been good to me so far..... Group: Admin Posts: 15,520 Joined: 11-September 03 From: Hurst, TX. Member No.: 1,143 Region Association: NineFourteenerVille |
Something is getting hot and causing the voltage to drop.
Work backward from the pump up the circuit. Check at each connection in the circuit. Example, check the wire where it leaves the relay board headed for the pump. If the problem is still there, then move to the input side of the relay. If the problem is still there, move up the circuit to the fuse, etc.... |
solex |
May 17 2010, 08:16 AM
Post
#3
|
Senior Member Group: Members Posts: 789 Joined: 12-January 05 From: Long Island, NY Member No.: 3,439 Region Association: North East States |
Something is getting hot and causing the voltage to drop. Work backward from the pump up the circuit. Check at each connection in the circuit. Example, check the wire where it leaves the relay board headed for the pump. If the problem is still there, then move to the input side of the relay. If the problem is still there, move up the circuit to the fuse, etc.... Steve, Clay am I looking for a constant 12 Volts when the key is in the run position? I'm a little confused as I expect the 12 volts for on 1.5 seconds unless the car is actually running. Dan |
Lo-Fi Version | Time is now: 10th June 2024 - 01:34 AM |
All rights reserved 914World.com © since 2002 |
914World.com is the fastest growing online 914 community! We have it all, classifieds, events, forums, vendors, parts, autocross, racing, technical articles, events calendar, newsletter, restoration, gallery, archives, history and more for your Porsche 914 ... |