New to mustang world. Have a 91' lx 2.3l with problems.

datboivinni

Member
Jul 25, 2019
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Dayton TX
I had the car running just the other day. Went to start next day and fuel pump wasn't turning on. It's a brand new pump. The ignition switch has also been replaced in the past. Just bought a new fuel pump relay thinking that's all it was. sadly, still nothing. When I jump the wires at the fuel pump relay plug I hear it turn on. Tried jumping it at the ecc test plug and nothing. Dont know much about electrical but know enough. I'm assuming there is something not allowing the relay to switch like it's supposed to. Could I just have really bad grounds? It had been sitting for a while before I received the car. Just can't figure this out and it's a bit frustrating for it to stop working out of no where. Any and all help isappreciated. TIA.
 
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Olivethefet

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May 17, 2018
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I dont believe that this is specific to V8 cars, but this is usually the first path people get pointed down when having the issues you are describing.


Let us know what you find out. It's important to follow in order even if you've checked out a few things already. Give it a good read then start checking out the car.
 

datboivinni

Member
Jul 25, 2019
9
3
13
17
Dayton TX
I dont believe that this is specific to V8 cars, but this is usually the first path people get pointed down when having the issues you are describing.


Let us know what you find out. It's important to follow in order even if you've checked out a few things already. Give it a good read then start checking out the car.
Will have to go through everything later in the day when I get off work to the best of my abilities. My 91' isnt carburated so I cant follow most of the steps. Its equipped with an efi system. Hopefully that doesn't complicate diagnosing it.
 

Olivethefet

Slap me as well as point and laugh
May 17, 2018
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Enterprise AL
You can use the checklist. It's specifically for fuel injected mustangs.

The checklist is called "Cranks OK, but No Start Checklist for Fuel Injected Mustangs"

Its equipped with an efi system

Just to be clear EFI means its fuel injected. Good luck! Let us know what you find or run into.
 

datboivinni

Member
Jul 25, 2019
9
3
13
17
Dayton TX
You can use the checklist. It's specifically for fuel injected mustangs.

The checklist is called "Cranks OK, but No Start Checklist for Fuel Injected Mustangs"




Just to be clear EFI means its fuel injected. Good luck! Let us know what you find or run into.
Electronic. I dont have a distributor but will still follow step by step.
 
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junkyardwarrior

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Jan 10, 2011
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If you can jumper the relay and make the pump work, but it won't work "normally", then something's not grounding the relay. The relay is grounded by the EEC when you first turn the key on at EEC boot, then again in cranking position, and finally once the EEC "sees" pip signal, it grounds the relay again. The relay is grounded to turn it on which makes connection between batt and fuel pump. You should have an IRCM which is where the fuel pump relay is, so I assume you've got the IRCM opened up in order to jumper the relay. I've had the trace burn on the IRCM circuit board in the past and that gave me some issues-so if you look close and see a burnt spot on the board, you found your problem.

The bad part about the 2.3L powered cars is that there is VERY little information online for them; most everything is 5.0 related and they are completely different. The 86-89 2.3's had a distributor and were somewhat similar but the later 2.3's were distributorless and had the relays inside the IRCM which is mounted on the passenger strut tower, has a sticker on it with a big letter (N, J, L, etc). I've known people that couldn't figure out why they wouldn't start or the a/c wouldnt' work and scrapped the car because of it; and that little box was all that was wrong with it. That's exactly now I got my '93 coupe. They couldn't figure it out (no fuel pump prime), offered it to me for $400 and I stopped at the junkyard on the way, grabbed an IRCM from a Taurus (and a spare just in case), bolted it on, started the engine and drove it home-277 miles.