 '74 1.8L LJet/fuel pump, Fuel Pump not staying on |
|
|
|
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. |
|
|
| RKramden |
 Jan 20 2020, 02:17 PM
Post
#1
|
|
Newbie  Group: Members Posts: 41 Joined: 26-October 19 From: So. California Member No.: 23,589 Region Association: Southern California  |
This is my first time starting a topic, I don't know if I am even typing in the correct location, but I am having an issue with my '74 LJet and fuel pump. The pump starts with the ignition switch, Pump also runs when Air sensor arm is manually moved. However when starting, it seems that the air sensor is somehow cutting off the fuel pump circuit. The PO had bent the arm so it never opened, but I have bent it back to move as designed. If I disconnect the electrical plug to the Air Sensor, the car starts and runs fine......any thoughts? BTW I have replaced the dual relay, but that did not fix the problem.
|
   |
 
|
  |
Replies
| RKramden |
Jan 21 2020, 03:11 PM
Post
#2
|
|
Newbie Group: Members Posts: 41 Joined: 26-October 19 From: So. California Member No.: 23,589 Region Association: Southern California |
thanks Clay, I will check all those things tonight. Big hose to Throttle body absolutly has holes. I have temporarily taped it up with a new one on order. I think I have the oil cap seal in the box of other stuff I have previously bought. All other vacuum hoses are new silicone but I will double check routing. What is puzzling me is that when I unplug the Air Flow Sensor, the car starts and stays running.
|
|
|
|
| jcd914 |
Jan 21 2020, 03:28 PM
Post
#3
|
|
Advanced Member Group: Members Posts: 2,090 Joined: 7-February 08 From: Sacramento, CA Member No.: 8,684 Region Association: Northern California |
QUOTE(RKramden @ Jan 21 2020, 01:11 PM)  thanks Clay, I will check all those things tonight. Big hose to Throttle body absolutly has holes. I have temporarily taped it up with a new one on order. I think I have the oil cap seal in the box of other stuff I have previously bought. All other vacuum hoses are new silicone but I will double check routing. What is puzzling me is that when I unplug the Air Flow Sensor, the car starts and stays running. There is a switch inside the Air Flow Sensor that until the flap moves the pump won't run. Disconnecting the Air Flow Sensor eliminates this fuel pump switch and the pump runs when the engine cranks over or the ECU sees an ignition pulse. It sound like the flap in the Air Flow Sensor does not move enough while cranking to close and allow the ECU to turn on the fuel pump. Jim |
|
|
|
Posts in this topic
RKramden '74 1.8L LJet/fuel pump Jan 20 2020, 02:17 PM
ndfrigi do you mind also sharing pic of your car and engin... Jan 20 2020, 02:35 PM
RKramden
do you mind also sharing pic of your car and engi... Jan 20 2020, 03:04 PM ClayPerrine Check where the engine harness plugs into the rela... Jan 21 2020, 01:56 PM RKramden I will check this evening, but I am getting fuel w... Jan 21 2020, 02:12 PM ClayPerrine
I will check this evening, but I am getting fuel ... Jan 21 2020, 02:19 PM ClayPerrine
I will check this evening, but I am getting fuel... Jan 21 2020, 02:20 PM dr914@autoatlanta.com with the key on and when you move the arm under th... Jan 21 2020, 03:44 PM porschetub
This is my first time starting a topic, I don... Jan 21 2020, 03:47 PM ClayPerrine
[
My understanding was that the pump only gets p... Jan 22 2020, 08:29 AM ndfrigi @rkramden I have spare AFM for Ljet, if you are a... Jan 21 2020, 05:04 PM RKramden Thanks All!!
So I checked the Vac lines, a... Jan 22 2020, 11:11 AM ClayPerrine Try these tests:
1. Disconnect the Yellow wire o... Jan 22 2020, 12:36 PM RKramden
Try these tests:
1. Disconnect the Yellow wire ... Jan 22 2020, 01:24 PM ClayPerrine
Try these tests:
1. Disconnect the Yellow wire... Jan 22 2020, 02:16 PM RKramden
[quote name='RKramden' post='2779785' date='Jan 2... Jan 23 2020, 10:12 AM ClayPerrine
Clay, I am leaning towards the AFM as the issue ... Jan 23 2020, 03:10 PM RKramden Interesting......just makes it harder for us novic... Jan 23 2020, 05:02 PM ndfrigi
Interesting......just makes it harder for us novi... Jan 23 2020, 07:51 PM RKramden I will check ohms on AFM this weekend. If they do... Jan 24 2020, 11:41 AM ClayPerrine
I will check ohms on AFM this weekend. If they d... Jan 24 2020, 01:55 PM RKramden I continuity tested all the wires from the ECU and... Jan 24 2020, 03:12 PM Rob-O
[quote name='RKramden' post='2780266' date='Jan 2... Jan 24 2020, 09:57 PM porschetub Are the wiper boards still being made by anybody ?... Jan 25 2020, 02:02 PM Rob-O The only ‘wiper boards’ I know of that we’re... Jan 25 2020, 04:02 PM Rob-O Forgot to add, I looked at Fuel Injection Corp’s... Jan 25 2020, 04:12 PM Rob-O BTW, you’re welcome to my old AFM. It had been ... Jan 25 2020, 04:25 PM RKramden SUCCESS---kind of
Ohm tested the AFM and was 290 b... Jan 27 2020, 08:29 AM ClayPerrine Now you know the harness is bad, so I suggest gett... Jan 27 2020, 08:46 AM RKramden
Now you know the harness is bad, so I suggest get... Jan 27 2020, 10:42 AM |
2 User(s) are reading this topic (2 Guests and 0 Anonymous Users)
0 Members:
|
Lo-Fi Version | Time is now: 30th April 2025 - 05:59 PM |
Invision Power Board
v9.1.4 © 2025 IPS, Inc.