1995 Mercury Grand Marquis - Crank/No Start

[friskyfrankie]

if you have power at both sides of the inertia switch, its either a ground, broken at the pump connector on the front of the tank, or most likely the pump itself. If the tank is full, its the pump, just because thats the most inconvenient time for a pump to fail.

Sounds about right! I'm too far away to go do it so that just proves geography CAN really be your best friend. I think he has someone, close by, that may be able to look at it and possibly do it in the next few weeks. I agree with wiring or bad pump. Too bad as I am told it is a Motorcraft pump with little mileage but 5-10 years since replaced. He did mention he was looking at a Delphi replacement as opposed to a "Autozone special". I didn't see a Duralast one available but only Delphi and Trugrade (whatever that is). I'll keep everyone here updated as the saga goes on. Poor guy has a hospital stay coming up in the next day or so - Hopefully, someone can help him out. I'm getting too old to be dropping tanks or trying to get it all done without dropping the tank! I know on the later GM's you can do it without dropping the tank but not sure on a '95!

[sly]

+1 pump.

There's one last thing to check... the ground on the chassis from that wire harness. Sometimes those come loose. I have no clue where it's located as mine never came loose. It should be on the wire loom going to the tank. Just follow it back towards the front of the car and there should be a bolt holding a ring terminal to the car somewhere for a ground.

+1 Delphi. That's what I just did for my Expedition. Didn't want to deal with the crap senders on the other designs.

[friskyfrankie]

+1 pump.

There's one last thing to check... the ground on the chassis from that wire harness. Sometimes those come loose. I have no clue where it's located as mine never came loose. It should be on the wire loom going to the tank. Just follow it back towards the front of the car and there should be a bolt holding a ring terminal to the car somewhere for a ground.

+1 Delphi. That's what I just did for my Expedition. Didn't want to deal with the crap senders on the other designs.

Great point - I'll pass the info along and hopefully whomever does the job is meticulous enough to check!

[friskyfrankie]

Just for curiosity sake, I wonder if you have to drop the gas tank to get to the fuel pump (removal and replacement) or if you can get it from the side passenger rear wheel area like on the later CV's and GM's?

[gadget73]

They changed to the all on one hanger system by 92 I think, so it should be able to come out the front. 80s models had the pump on the rear plate up against the trunk so it wasn't possible. I'm not quite sure what 90-91 models did.

[sly]

90+ did the everything on the hanger. So assembly at once.

[friskyfrankie]

90+ did the everything on the hanger. So assembly at once.

Yes, so I take it that removal (of the entire assembly) IS possible without dropping the tank?

[sly]

Yes, so I take it that removal (of the entire assembly) IS possible without dropping the tank?

Yes. Drain off as much fuel as possible before unbolting the fuel pump I had to use a hand pump on the pressure line from the pump hanger to do it on my wife's car. That took a good hour to do and she only had 3/4 of a tank. Getting the fuel down to 1/3 to 1/4 of a tank will prevent spilling fuel everywhere. The fuel filler has a block in it to prevent using a siphon to steal gas, so that's not an option. The return line may be usable if it doesn't have a one-way valve on it, but if you try to pump that side and nothing works, the one-way valve is present.

[friskyfrankie]

GREAT info - I'll pass it along. Might happen Wednesday (weather permitting) so we'll see and if so, I'll post the results.

[friskyfrankie]

Just as an update - it wound up being the main computer (PCM/ECU/ECM or whatever it is termed)! There was a P0401 code even though everything checked out ok. Wonder if it will come back. A/C is even colder. Let's see how things turn out long term....just got the news today. Friend is still in and out of the hospital but at least we hope the car update provides some comfort!

[sly]

Yeah... PCM is always possible since it controls the relays. Not the first I've heard of doing this, though I can still count them on one hand.

[friskyfrankie]

Yeah everything else checked out ok (from what I was told) so the PCM was the only thing left. No one knows what "took it out" plus I don't know if it needs to learn all the functions of the car but was told it didn't need to be programmed and the car started right up after it's installation.

[sly]

Yeah... these are old enough that the only learning that they really do is fuel trim and idle air control variances between engines. They expect all sensors to be within spec.

[gadget73]

What he said. It will figure itself out after a couple of cold start to fully warmed up drive cycles.


might want to have them check the battery voltage to make sure the alternator isn't doing something dumb. High voltage or a large amount of ripple from a bad diode can smoke electronics.

[friskyfrankie]

What he said. It will figure itself out after a couple of cold start to fully warmed up drive cycles.


might want to have them check the battery voltage to make sure the alternator isn't doing something dumb. High voltage or a large amount of ripple from a bad diode can smoke electronics.

Excellent idea about the alternator - will pass it along!