89 FUEL PUMP RELAY QUESTION - Page 3 - Rennlist - Porsche Discussion Forums

Notices
928 Forum
Sponsored by:
Sponsored by: 928 Specialists

89 FUEL PUMP RELAY QUESTION

 
Old 01-10-2019, 07:26 PM
  #31  
Kevin in Atlanta
Addict
Rennlist Member
 
Join Date: May 2002
Location: Roswell, GA
Posts: 4,828
Default

Originally Posted by jeff spahn View Post


A good question I have is why are you connecting #85 on FP relay (relay 20) to socket 21 on connector W (which connects to #85 on LH relay (relay 25). Is there any reason why you just couldnĺt connect #85 on FP relay (relay 20) to #85 on LH relay (relay 25)?
Me? Not me. That was at the direction of Greg Brown.
Kevin in Atlanta is offline  
Old 01-10-2019, 07:38 PM
  #32  
jeff spahn
Addict
Rennlist Member
 
jeff spahn's Avatar
 
Join Date: Nov 2009
Location: Dubuque, IA
Posts: 7,382
Default

Deleted.
jeff spahn is offline  
Old 01-10-2019, 10:16 PM
  #33  
polecat702
Vegas, Baby!
Rennlist Member
 
polecat702's Avatar
 
Join Date: May 2009
Location: far away
Posts: 10,493
Default

Jeff, spoke with Louis Ott, and after discussing every thing that we've done to diagnose the problem, Louis agreed it's probably in the LH computer. I'm pulling it out tomorrow morning, and sending it back to Louis. Electrical ain't my strong suit, and I just let the car sit for most of the year. It would still be sitting if Jeff hadn't come out to help me out!

Runs like a scalded cat with a jumper wire. It's like that old saying:" If it's got **** or tires it'll give ya problems."
polecat702 is offline  
Old 01-10-2019, 11:00 PM
  #34  
Mrmerlin
Petie3rd
Rennlist Member

This Post Sponsored by:
Dow Corning« & DeoxIT«
 
Mrmerlin's Avatar
 
Join Date: May 2004
Location: Philly PA
Posts: 22,363
Default

Its great that Jeff came out to assist you,
we will figure this out, one way or another,
sorry I have not been able to launch.
The thing thats bothering me is the remark that the car has had a cutting out issue from day one,
This sounds like a crossed wire shorting something. maybe a pinched harness from when she was built,
and so far it has not been found.
I wonder if this same issue could be damaging the LH if infact it is damaged.
Thats why it would be good to swap this LH into a good running machine to test it
Ima keep noodling this
Mrmerlin is online now  
Old 01-11-2019, 06:32 PM
  #35  
jeff spahn
Addict
Rennlist Member
 
jeff spahn's Avatar
 
Join Date: Nov 2009
Location: Dubuque, IA
Posts: 7,382
Default

Joe is prepared to pull the entire harness out of the car and put in a new one. He has another harness and is prepared to test continuity of every wire in that harness prior to install. Extreme but would eliminate the problems as long as it didn't cause others.
jeff spahn is offline  
Old 01-11-2019, 07:01 PM
  #36  
dr bob
Chronic Tool Dropper
Lifetime Rennlist
Member
 
dr bob's Avatar
 
Join Date: Oct 2001
Location: Bend, Oregon
Posts: 17,396
Default

Would be interesting to get the results of the power and ground testing at the FP relay socket. I suspect that relay ground through the LH is based on the connection at the back of the intake, same one that injectors depend on. Make short jumpers so you can dangle the relay a bit away from the CE panel and read voltages in service.

If the FP doesn't run with FP relay jumpered, look hard at the fuel pump power circuit that starts at one of the smaller red wires at the battery positive. More than a few wacko FP symptoms start with a less-than-stellar connection at the battery terminals.
dr bob is offline  
Old 01-13-2019, 05:57 PM
  #37  
jeff spahn
Addict
Rennlist Member
 
jeff spahn's Avatar
 
Join Date: Nov 2009
Location: Dubuque, IA
Posts: 7,382
Default

We are able to run it jumped.
jeff spahn is offline  
 


Thread Tools
Search this Thread

Contact Us About Us Advertising Cookie Policy Privacy Statement Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: