Fuel 1990 LX 2.3 hot no start

LA racing · Sep 25, 2024

i have a 1990 mustang 2.3 with a hot no start issue and i am pulling my hair out.
it will run perfectly for 15-45 minutes and then shuts off and wont start for 45min to 3 hours.

will start on starting fluid and run perfectly and immediately shuts of when taken away.
fuel pressure is good at 38psi.

fuel injectors have power and are receiving a pulse. i could be testing this wrong but i get the exact same results when the car running to it not running.

PLEASE HELP.

AeroCoupe · Sep 25, 2024

Have you pulled codes? The check engine light (CEL) only illuminates for emissions related codes so there could be other codes present.

LA racing · Sep 25, 2024

AeroCoupe said:
Have you pulled codes? The check engine light (CEL) only illuminates for emissions related codes so there could be other codes present.

There are no codes

AeroCoupe · Sep 26, 2024

What is the battery voltage measuring when it is running?

LA racing · Sep 26, 2024

AeroCoupe said:
What is the battery voltage measuring when it is running?

13.8

89ripper · Sep 28, 2024

So...no codes, what do you mean by, "taken away"? Like only starter fluid keeps it running?

LA racing · Sep 28, 2024

89ripper said:
So...no codes, what do you mean by, "taken away"? Like only starter fluid keeps it running?

Yes only starter fluid will keep it running.
I have double checked my fuel pressure and it is good.
I have double checked if I am getting injector pulse.

89ripper · Sep 28, 2024

When you crank, cranks just fine not like slow cranking or anything like that. You are getting injector pulse you said?

LA racing · Sep 28, 2024

89ripper said:
When you crank, cranks just fine not like slow cranking or anything like that. You are getting injector pulse you said?

Cranks over perfectly.
Injectors are getting a pulse.

89ripper · Sep 28, 2024

Well the next thing to rule out would be spark. If you are telling me fuel pressure is good/and the injectors are pulsing I would be curious about spark. Do you know how to test for that? I do understand you can get the car to start with starting fluid, but maybe you have weak coil when hot.

LA racing · Sep 28, 2024

89ripper said:
Well the next thing to rule out would be spark. If you are telling me fuel pressure is good/and the injectors are pulsing I would be curious about spark. Do you know how to test for that? I do understand you can get the car to start with starting fluid, but maybe you have weak coil when hot.

I have replaced the coil and it didn't change anything. I have swapped over to the other coil when the car is hot and still no different

89ripper · Sep 28, 2024

How do your engine grounds look? Battery connections, grounds, check these make sure nothing is corroded. How does car act on cold starts? Long cranking or start right away?

LA racing · Sep 28, 2024

89ripper said:
How do your engine grounds look? Battery connections, grounds, check these make sure nothing is corroded. How does car act on cold starts? Long cranking or start right away?

Engine grounds look good I added an extra one just incase.
Battery connections look good 0 corrosion.
When cold it starts up quickly and runs perfectly for 15 to 45 minutes.
If I let it sit in the drive way with the hood closed it will heat up and run for 15 minutes before it shuts off.
If I drive it around it will last 45 minutes before shutting off.
When driving it has full power no hesitation and seemingly no problems

89ripper · Sep 28, 2024

You could be dealing with a couple different problems here. I didnt know it was shutting off on its own like that. I have a high mileage 5.0. Hot starts can be a bit tricky, ive learned something about timing. Too much timing can make it hard to start so ive had to back the timing off.
Not at all suggesting this is one of your problems but curious have you ever cranked while holding gas pedal part way?
Ever tested your icm? I assume ford used one on these...lmk if this isnt the case.

LA racing · Sep 28, 2024

89ripper said:
You could be dealing with a couple different problems here. I didnt know it was shutting off on its own like that. I have a high mileage 5.0. Hot starts can be a bit tricky, ive learned something about timing. Too much timing can make it hard to start so ive had to back the timing off.
Not at all suggesting this is one of your problems but curious have you ever cranked while holding gas pedal part way?
Ever tested your icm? I assume ford used one on these...lmk if this isnt the case.

I have tried retarding the timing.
I have tryed giving it gas to start it.
Also when it decides to shut off it will do it under wide open throttle as well

89ripper · Sep 28, 2024

For clarification, when you hold down pedal, you arent giving it gas you are holding throttle open to allow air in. Putting it to floor will shut off injectors, i only wanted to see how your car was reacting. You didnt answer about your icm. Its a cause of a lot of stalling when hot.

LA racing · Sep 28, 2024

89ripper said:
For clarification, when you hold down pedal, you arent giving it gas you are holding throttle open to allow air in. Putting it to floor will shut off injectors, i only wanted to see how your car was reacting. You didnt answer about your icm. Its a cause of a lot of stalling when hot.

It doesn't start at any throttle position.
I have replaced the ignition control module. And the pip. I have replaced the ICM when it's warm and it stil won't start.

89ripper · Sep 28, 2024

LA racing said:
It doesn't start at any throttle position.
I have replaced the ignition control module. And the pip. I have replaced the ICM when it's warm and it stil won't start.

Its a point of contention with us mustang guys. Long ago we would search for only motorcraft icms as different ones have been found to be bad right out of the box. They are hard to come by these days.

Pardon Our Interruption...

Having one of those helps so you arent barking up the wrong tree. You are using the right kind of paste to install the module right? Just trying to cover all bases.

We have a no start list for our 5.0s. and im not sure how much that will help you but ill look into seeing what the process is for your engine.

It took me many years to get my car running right. I would stall out at lights, slow crank hot starts, all that jazz.
Also i want to ask you what you mean the injectors are getting a pulse but that you may be doing this wrong...

LA racing · Sep 28, 2024

89ripper said:
Its a point of contention with us mustang guys. Long ago we would search for only motorcraft icms as different ones have been found to be bad right out of the box. They are hard to come by these days.

Pardon Our Interruption...

Having one of those helps so you arent barking up the wrong tree. You are using the right kind of paste to install the module right? Just trying to cover all bases.

We have a no start list for our 5.0s. and im not sure how much that will help you but ill look into seeing what the process is for your engine.

It took me many years to get my car running right. I would stall out at lights, slow crank hot starts, all that jazz.
Also i want to ask you what you mean the injectors are getting a pulse but that you may be doing this wrong...

Both of the ICM's I have are Motorcraft.
the car runs good when cold with Both of them. I have put in the other ICM when the car is hot to see if I had 2 failed ICM's and it still wasn't firing.

I first checked the injector pulse and it seemed a little odd to me.
Second check I took the plug apart and got my test light on both leads very securely and it was flashing very nicely

89ripper · Sep 28, 2024

This is why i was thinking you had multiple problems and not just one. Since you have 2 "motorcraft" icms, we will put that aside for now. I put it in quotes because 9 out of 10 times they arent actually motorcraft.
I was thinking the icm was getting hot and causing it to stall- that would be one problem. How many miles on this engine?

Fuel 1990 LX 2.3 hot no start

LA racing

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lube between the nut and the face. I know my lubes

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