Fuel Low voltage at pump harness plug.

[Titusvillefox89]

1993 2.3 NA. Car has been fine and reliable for the most part. A few months ago the fuel pump died. Changed it out with a quality OEM part. This morning my wife took the car to work. Car ran fine, seemed a little sluggish she said. Then when she went to leave it wouldn't start. Like normal I expected the car to just behave after I got there but it wouldn't start for me either. Pump was not priming. Checked voltage at the pigtail for the inertia switch and it only had something like 7 or 9 volts going in and out. Checked the fuel pump pigtail connector above the tank and again, with key on it didn't have 12 volts. About the same as the inertia switch. Over read the articles on pump diag 101. I'm waiting for the car to get towed home at the moment so I can play with it. My question/comment is ; if any fusible link was bad there would be nothing at all cause they basically function like fuses. Now with that in mind, why would I have low voltage to the back end of the car and does the pump really need 12v to trigger it on? If so, is it even possible that the relay could cause this condition?
Thanks

 

[91TwighlightGT]

Your fuel pump relay is integrated into the problematic IRCM. It is always a suspect. You can try tapping on the box while cranking the car and see if it kicks on. The IRCM is rebuildable, which may be worth it because they are kinda pricey.

 

[Titusvillefox89]

Fuel pump relay is in the box on the passenger side strut tower? I thought it was located almost directly under the MAF sensor on the air box? I haven't looked under the hood of this poor car in a while lol. Where can I get another relay? Whether it's bad or not it may be worth it just to change it out for piece of mind. I know most places have the wrong relay lol

 

[91TwighlightGT]

Yeah, it is a different setup than the 5.0L cars.

You can check this out if you want to try to repair your IRCM.

NATO - Ford IRCM Schematic & Troubleshooting

If you don't attempt your own repair, then you have to buy a new IRCM. They aren't all that cheap, unfortunately. I believe you can buy them from local parts stores or Rockauto.com still, however. Obviously with the part being expensive, you will definitely want to verify that this is your actual problem first.

 

[Titusvillefox89]

Ok, so update. Got the car home. Didn't touch a thing. Fuel pump primed just fine. Fan cycles just fine. Car is running fine. Checked fuel pressure. With vac on it's a solid 32psi. Has not acted up at all so far. Charging system and battery are ok too. Right now I am letting it warm up. Fan has cycled twice. Will update. Also voltage at the pump is a solid 13v will running.

 

[General karthief]

Start wiggling wires. Especially where the fuseable links are

 

[Titusvillefox89]

Update :
The car continues to act normal. Drove to the store and back. Shutdown and restart like normal. No hiccups. Also should note. Ever since I had the car for probably 2 years now. If you hit the key to crank it over and then stop before it fires, let the starter spin down and try to start again, it acts like it either loses spark or fuel cause it wont fire. It acts like it wants to fire but cant. Never really thought much of it until now. Could be related?

 

[General karthief]

yesmaybe
Check the ignition switch under the dash, look for discolored/loose wires at the plug, they are failure prone.

 

[Titusvillefox89]

yesmaybe
Check the ignition switch under the dash, look for discolored/loose wires at the plug, they are failure prone.

Will check to light after work. Only time I have ever been in the column was when we pulled the cluster to upgrade to LED lighting.

 

[General karthief]

The switch is under the dash above the peddles on the column, not up by the key