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

1012 Views 6 Replies 5 Participants Last post by Shawnryan, 5 mo ago

Moses

Discussion Starter · 5 mo ago

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.

Thanks,
Mo

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OX1

· #3 · 5 mo ago

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.

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OX1

· #5 · 5 mo ago

Moses said:
Thanks for the replies and suggestions. And I'm relieved to hear the gas wouldn't gum up that fast in the system. I've had gas gum-up on me in my tractor after sitting for a few months and had to pull the carb and clean it out, but again, different type of system and different conditions.

As far as the ECU goes, Tbh, I don't know what's in it. I just bought the vehicle this past August and got only limited info on what was done to it by the prior owner but not a full list. I had it Dyno tuned back in September by local mustang shop when the injectors were upgraded and yeah now that you mentioned it, I'm surprised the plugs weren't replaced either. At the time though I was forking over a ton of cash to rebuild the rear-end (it had a spool in it, some suspension parts were worn out), and my only guess is that with the exception of having to replace the ignition coil and upgrading the injectors, it was making good and consistent power on the dyno, so they didn't do any work I didn't ask for unless it absolutely needed to be done. I can't really complain about that. I will do the plugs when the weather breaks up here. But my fuel gauge is stuck at FULL, so I'm guessing the fuel sending relay is shot also; while that's getting replaced, I should do the fuel filter too. The list just keeps growing.

I will try starting it with the carb cleaner as suggested.

Thanks!
Mo

There is also no reason you cannot check spark the way you normally would (IE, spark plug tester, etc...)

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