93 SHO 3.0L Will Not Start (New Fuel Pump NOT Priming)

[Plasticmatt477]

I recently posted about my SHO starting/running/idling fine until I restart when hot. Once I tried to restart it I would either start back up and die off or I would have to floor it to keep the engine running.

I thought the new fuel pump would fix this and it seemed to work until the second time I tried to go for a cruise. This time NOTHING... no fuel pump priming or even a hesitant start... Engine cranks and no fuel.

I have measured the voltage at the inertia switch and when the key is first turned on 12v + or -... after a sec or two it drops right off to around 6.5v and stays there. My question is, is the inertia switch the last switch/relay/module before the pump? If so, would this be bad wiring to the pump? or possibly corroded ground wire? It is a brand new pump, but when I installed it I did not check the wiring which I wish I would have because it turned right on.

Thanks,
Matt

 

[Shovert]

It is last thing to pump. Are sure got a good ground for the volt meter? This has messed me up several times. Best places I find it head of screw or bolt. The power for it come from the IRCM in engine bay. Check voltage there when trying on same color wire as the power feeding the inertia switch. On a 94 diagram I am using it is pnk-blk of pin 5 at the ircm. You can try grounding at the test connection and see if it pumps. Unsure which one that is someone else will have to help there. Maurice

 

[Plasticmatt477]

Firstly, Nice SHOStang! (photobucket)

Yes, i'm actually testing the same way you do (head of bolt) haha. From what I understand, 12v on key on for 1 or 2 seconds is normal right? This would be for priming? I'm by far not an expert... just ALOT of google! lol

OOO is the black box under the radiator cover the IRCM? I will go look at the wire colors to see if any match, but i'm thinking its the same as yours or orange and black...

If anyone has more information on the test connection please advise... I will be working on this tonight and tomorrow (or until its fixed haha).

I will get back to you with the voltage at the IRCM (as long as i'm right on which module it is...)

Thanks for the reply!

 

[Shovert]

Ircm looks like this.
http://jrthecar.com/articles/ircm/index.html
Going from memory when I unwired my engine from body years ago. I think it is near radiator but mine was a 3.2 motor and I am from from my memory. You have been warned. Maurice
Ircm info. Maybe of some help.
http://www.shoforum.com/showthread.php?t=75065

 

[Plasticmatt477]

Ok, I know exactly where thats at. Thanks for the pic, ill feel better about my reply tomorrow since I am positive thats it. I will def let you know what i get.
Thanks again,
Matt

 

[General Geoff]

I had this EXACT problem with my 1993 3.0l. Was getting inconsistent voltage at the inertia switch.


I ran a new wire (with inline 15A fuse) from the CCRM to the inertia switch, through the firewall, under the dash, along the rocker panel (under the plastic trim), behind the rear seat and into the trunk. The car has run without a single problem for several thousand miles since then.

 

[Plasticmatt477]

It has been freezing outside and I dont have a garage, but I should have the results for you tomorrow Shovert!
AlsoGeneral, Thanks for the suggestion and honestly at this point it wouldnt be a bad idea to start running new wires to "make sure"!!!