Ford Mustang Forum banner

1989 LX 5.0 Cranks but won't start after sitting a few weeks

1020 Views 6 Replies 5 Participants Last post by  Shawnryan
Just trying to figure out what I should be looking for.

Car had alternator upgraded to 150amp recently by local Mustang shop and had the P/S pump pulley replaced with a larger diameter pulley to stop the tensioner pulley from rubbing against the W/P pulley. The oem starter was starting to seize up, so it was also replaced with a hi-torque ministarter from LMR. All cables were upgraded as well as the starter solenoid. It was starting and running fine when I brought it home (1st week of December 2022).
Fuel tank was under a quarter tank, so I filled the tank with 93 oct, added some stabilizer and put it to bed. It has a Vortech V1.

We had some nice weather this past weekend up in southeastern MA, so I tried to start it. It cranked strong but wouldn't start. I could hear the fuel pump kick on when the key was moved into ON position, as expected. Visual inspection under the hood didn't reveal any loose, disconnected or CHEWED wires (i.e. rodent damage).

Injectors are all brand new. If this was my tractor, my first guess would be that it wasn't getting fuel and I'd likely suspect my carburetor had gummed up from letting the gas sit in it for a few weeks even with the stabilizer (damn ethanol). But this ain't my tractor and this engine doesn't have a carburetor, so I'm looking for suggestions on how to troubleshoot this, given I can hear the fuel pump running.

A few other things to note:

  • I have no idea when the fuel filter was replaced last;
  • I don't know when the last time the plugs were changed;
  • I bought the car with 74k this past August. It's been dyno'd and tuned since and fuel pressure checked out fine, and wasn't made aware of any spark issues.
  • I don't own a fuel pressure gauge.

1 - 1 of 7 Posts
A few weeks will not "gum up" ethanol fuel, especially with stabilizers. Easily good for 3 months, and that is gas open to the atmosphere, like a carb bowl with an open vent on top of carb. EFI with closed fuel systems are good for up to a year with stabilizers (my EFI boat sat for a year and half during COVID, no issue at all with marine Stabil) . My 86 Capri also sits for LONG periods of time (again, upwards of a year sometimes), still OK.

I am surprised you had car dynoed/tuned on unknown spark plugs. Most decent tuners want new plugs to even start tuning. Most likely not your problem, but won't hurt
to swap them out. You might stumble on something loose in all the replaced electrical system, while doing plugs.
Take a fuel sample. You may have just gotten ****** bad gas. But ethanol attracts moisture. And destroys stock fuel systems. Check fuel pressure and flow also. Keep us posted.
1 - 1 of 7 Posts