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1990 Grand Marquis won't start. We replaced the fuel pump and fuel filter, spark plugs and wires. We had no issues after each set of maintenance. My son even drove it to school a couple of times. Yesterday I drove it less than 1/4 mile and it died and would not start again. Only cranks and doesn't run. Any ideas?

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  • Is fuel getting to the sparkplugs / combustion chamber? Is there a spark at the plugs?
    – Solar Mike
    May 30, 2019 at 13:15
  • Solar Mike, it dosent feel like it. Additionally, I pushed the pitcock to see if fuel would spray due to psi from the fuel pump. There was nothing, not even a trickle. I'm thinking relays need to be replaced.
    – Charles E Godwin
    May 30, 2019 at 14:32

1 Answer 1

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Put a fuel pressure gauge on the Schrader valve. This will tell you for sure you're not getting any fuel pressure. Once verified, there are basically four things to look at:

  1. Check your fuses/relays in the underhood fuse box to ensure nothing it blown. You can swap out relay(s) with known good ones. These should all be pretty much be standard.
  2. If the fuses/relays check out, more than likely the fuel pump you got died. This is not uncommon. It will, in most cases, have a warranty on it so you should be able to get a free replacement ... if you did the work yourself, you're only out your time.
  3. (EDIT) If you can hear the fuel pump and you're not getting pressure at the rail, this means the relay is good, but the fuel is not getting to the injectors. You replaced the fuel filter, which means it's not plugged. It could be the hose running from the fuel pump to the transfer tube (the pipe attached to the part which seals the tank and carries the pump) has come loose or has sprung a leak. It's only a hose clamp which holds it on both ends (pump and tube side). If it wasn't tightened when the pump was replaced, it could have popped off. If it has sprung a leak because it wasn't replaced when the pump was, it could easily bust. They do deteriorate over time.
  4. (EDIT) Just because you can hear the fuel pump, doesn't mean it hasn't stopped working. The main shaft could have separated from the pump impeller (or however it drives the pump), which can allow the pump motor to continue working, yet won't create fuel pressure. I've seen stranger things.

With either of 2, 3, or 4 above, you're still looking at dropping the tank. PITB, I know.

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  • Paulster, I can hear the fuel pump cycle. is a dead fuel pump still a choice?
    – Charles E Godwin
    May 30, 2019 at 16:41
  • @CharlesEGodwin - Yes it is. Check the #3 & #4 edits.
    – Pᴀᴜʟsᴛᴇʀ2 ♦
    May 30, 2019 at 18:23
  • Ok, when we pulled the mercury out of the yard, we replaced the fuel pump and cleaned out the gas tank, added seafoam and filled it. 2, 3, and 4 are definintly looking like the problem, thanks for your help. And now im off to rockauto.com for a new tank. thanks a bunch
    – Charles E Godwin
    May 30, 2019 at 21:28

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