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blackf3504dr · 08-05-2012, 03:41 AM

I got the no spark problem solved and it was running great. I went to start it yesterday and it turns over fine but won't start, I don't hear the fuel pump come on so I checked the relay. The relay did nothing when energized so I replace it, now the relay "clicks" when the key is turned to the run position but nothing from the pump (new a year ago).
I measured the voltage at the connector for the pump and it's 8.4V (yellow wire), I think it may be a ground issue but would like some thoughts as to what may be going on. It's a '92 HR on a '91 F53 chassis...

subford · 08-05-2012, 05:34 AM

The yellow wire has nothing to do with the fuel pump system.
The yellow wire is part of the fuel tank gauge system for the cluster.

You should have two relays mounted together. Do both click when the key is turned on and one of drops out one second later?

If not you might try resetting the fuel shutoff safety (Inertia) switch.

Note that the fuel pump relay only stays made for one second when the key is turned on unless you ground pin #6 of the self-test connector then it will stay made (on) all the time the key is on. So you will only have power on the fuel pumps wire for one second each time the key is turned on or for one second each time the computer sees a PIP pulse from the distributor.

Your fuel wiring should be like the wiring diagram below but the wire colors may not all be the same.

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blackf3504dr · 08-05-2012, 08:33 AM

The distribution bar on the radiator support has a terminal marked FP, I "assumed" that meant fuel pump and leads to single a relay mounted about two inches to the right of the distribution bar. I wasn't aware there are two relays in tandem, do you know where they are mounted ? The inertia switch seems to be fine and the plunger is not extended. The distribution bar is to the left with the relay to it's right.
This old motor home is giving me fits....

TXiceman · 08-05-2012, 08:33 AM

Start by checking ground connections.

Ken

subford · 08-05-2012, 02:55 PM

They should be in the location in the diagram below.
I do not know what that distribution bar and switch is for as it is non Ford. More than likely has to do with the home that is on the F53.

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blackf3504dr · 08-06-2012, 04:58 AM

Quote:

Originally Posted by TXiceman

Start by checking ground connections.

Ken

Hey Ken, I checked and cleaned the engine grounds when I had the spark problem. Are there grounds further down the line for the fuel pump ?

Thanks for the diagram Bill, I'll check that out .

blackf3504dr · 08-07-2012, 03:38 PM

I replaced both relays this morning and it fired right up. Started it five or six times and it started every time, hopefully it's good to go !
Thanks guys.