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-   -   No fuel pressure when cranking. (https://www.mercuryforum.com/forum/general-tech-help-12/no-fuel-pressure-when-cranking-5782/)

MarquisDeSade 09-08-2011 09:07 PM

No fuel pressure when cranking.
 
To begin with: Hi! I'm Jonny and I'm new to the forums. I'm coming here to hear the wisdom of people who might have a clue as to how to help me.

Vehicle: 1996 Grand Marquis LS


After replacing my lower ball joints (one sheared on me while driving), I promptly let my car down and prepared to take her on a test run. When I tried to start it, the engine kept cranking and cranking, no sign of life. Upon further inspection, I noticed that not only is the fuel pump not priming, the relays aren't clicking. There is 0 fuel in the rails, and I've yet to check for spark (need a second person for that).

My brother and I are tackling this head on. The fuel filter was not clogged (checked and changed), the grounds seem clean (cleaned and reattached), and when the EEC relays are bridged/shorted, the fuel pump kicks on (so it's not the fuel pump as far as I can tell). I've replaced the PCM/EEC with two others with the same problem. Oil levels, etc are all good. We did notice that my master cylinder may have a slow leak that was causing cruddy rust to be all over everything beneath it (including two connectors that appear clean on the inside/ wires fine). The only thing I can think of to try is to completely trace the entire EEC line and go over each and every wire to make sure nothing is awry.

We've even checked the ignition switch, all appears well and clean. We've checked the pins at the PCM connector and all grounds are good to go. We did notice that there appears to be not enough voltage coming through from the fuse box to the EEC relay station.

If anyone has any ideas or suggestions (or even a derogatory insult calling me a rookie and pointing out a solution) I would be very, very grateful. It's my only car/primary driver and bumming rides to work is becoming old.

Thanks!
-Jonny-

jakesulivan 09-12-2011 12:27 PM

Did your problem got solved or you are still looking for solutions?

MarquisDeSade 09-12-2011 04:06 PM

I'm still looking for solutions. We've narrowed it down to it definitely being an electrical problem. My coils test good, and power to the EEC is happening, it's just not making it to the PCM (the relays aren't getting the command signals). All fuses at all locations are at 100%.

Basically it seems like everything is good, except there's a wire or a circuit somewhere that isn't operating like it should, and is screwing the whole process up.

--------- Scratch that!-----------

We solved it. My father stepped in (master of the electronics world) and we quickly isolated a few wires that had been damaged during the ball-joint-bottom-out fiasco. In short, three wires just past the C104 connection behind the driver side front wheel well had been hit/pinched/scraped, resulting in two severed wires and one with the insulation ripped partially off. A few touches with an iron and some electrical tape/heat shrink solved the issue. My beast is purring like a lopsided kitten once more.


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