Fox T-Bird/Cougar Forums

Technical => Engine Tech => Topic started by: Cougar8775 on June 11, 2010, 04:13:33 PM

Title: engine stays running with key off.....
Post by: Cougar8775 on June 11, 2010, 04:13:33 PM
Now i got the TC back together and took it for its voyage today and after bout 20 min of driving i go to shut the car down it continues to run as if i never turned the key off. And the Ign switch is new. So what could it be? Ign coil wire staying energized with key off? Would that keep it running? Oh and to add to the voyage the boost peaked at 10 psi and the car felt like it was running out of fuel (lean) so im not pushing it any further. I just might turn the boost down a bit. But if anyone knows why the car runs after key off please let me know. This could get bad for a turbo car.
Title: engine stays running with key off.....
Post by: sarjxxx on June 12, 2010, 02:47:35 AM
Don't think its the coil, B/c your fuel pump should shut off with the key and would starve the engine.

How long did it run for? Did all the dash lights and guages and everything shut down like normal?
Title: engine stays running with key off.....
Post by: Cougar8775 on June 12, 2010, 09:29:13 AM
yeah everything shutdown like usual but not the engine. strange i know.
Title: engine stays running with key off.....
Post by: TurboCoupe50 on June 12, 2010, 10:42:34 AM
Anything that keeps power to the R/G wire feeding the ign coil will prevent engine cutoff.. Power is fed from the ign sw to a fuse link by the starter solenoid, then to the coil and the EEC relay(inside the IRCM)... There is also a feed back to the regulator inside the alternator, any chance you have a wiring issue at the Alt???
Title: engine stays running with key off.....
Post by: softtouch on June 12, 2010, 02:54:43 PM
Also try pulling fuse 18. A wiring problem on something fed by fuse 18 could feed back into the ignition/ECU power circuit.
Title: engine stays running with key off.....
Post by: Cougar8775 on June 12, 2010, 08:15:44 PM
Those are good solutions. But what i have found out is when it stays running i let it idle down to cool off the turbo, then i just dump the clutch to stall it but fans do keep running. So i pull neg cable from the bat and once i do that i hear a click from the ircm. So thats telling me one the relay is staying stuck open even with the key off and the wires are messed up somewhere. So i have some digging to do tomorrow to get this all situated. And yes i will keep everyone up to date on it. And will check out what everyone has stated.
Title: engine stays running with key off.....
Post by: Cougar8775 on June 13, 2010, 02:20:39 PM
got it figured out... Its coming back that the ircm is bad. So looks like time to replace it. Now can anyone tell me if the 90 SC ircm is a direct swap?
Title: engine stays running with key off.....
Post by: Cougar8775 on June 14, 2010, 08:15:01 PM
ok so today i put in the ircm from my 90 sc and it did work but i didn't have the fuel pump running with that ircm. So i stuck my old one on it and did some tests. Before i got no power to the r/g wire on the coil. After the swap i had power. So i started it let it idle then went to shut it off and it shut off on its own. So Can someone explane to me what happened? How did it fix itself?
Title: engine stays running with key off.....
Post by: TurboCoupe50 on June 14, 2010, 08:56:50 PM
Could have been a stuck relay, which means it was still closed even there was no power applied... If so it'll likely happen again...
Title: engine stays running with key off.....
Post by: Cougar8775 on June 15, 2010, 09:08:38 AM
yeah im sure it will thats why im hitting sone JY's to find me a new ircm.