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-   -   89 FUEL PUMP RELAY QUESTION (https://rennlist.com/forums/928-forum/1114362-89-fuel-pump-relay-question.html)

Kevin in Atlanta 01-10-2019 06:26 PM


Originally Posted by jeff spahn (Post 15556786)


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 couldn’t 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.

jeff spahn 01-10-2019 06:38 PM

Deleted.

polecat702 01-10-2019 09:16 PM

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 tits or tires it'll give ya problems."

Mrmerlin 01-10-2019 10:00 PM

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

jeff spahn 01-11-2019 05:32 PM

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.

dr bob 01-11-2019 06:01 PM

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.

jeff spahn 01-13-2019 04:57 PM

We are able to run it jumped.


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