car will run fien then just shuts off

**90TitaniumStang** · 02-25-2009, 12:50 AM

hey guys i went up and got a new tfi module harness from lou today hoping it was the problem but it didn't fix the problem
my 90 lx is running fine then it will all of a sudden just shut off like i turn a switch
it will start back up though but will then shut off after ten to fifteen seconds then let it cool back down and it will run fine for a while then act up again any suggestions
i have replaced the pickup coil inside the msd distributor, the harness for the tfi, tested the msd and coil, new tps, and new idle air, cleaned all grounds
this is the first time i have needed help and any would be greatly appreciated

**Martin0660** · 02-25-2009, 12:44 PM

Originally Posted by 90TitaniumStang

i have replaced the pickup coil inside the msd distributor, the harness for the tfi, tested the msd and coil, new tps, and new idle air, cleaned all grounds

I did not see the TFI module itself on this list??? The only way they will show up as bad in testing is for them to be in a failed condition )and it isnt when it cools down). Sounds like classic TFI that it runs when cooled off.

**White5.0** · 02-25-2009, 12:54 PM

i agree with above post, its most likely the module itself, not the harness

**mustang50lx** · 02-25-2009, 01:28 PM

If its not the TFI module try the EEC relay and the fuel pump relay too.

**90TitaniumStang** · 02-25-2009, 04:54 PM

i did the module im sorry i thought i put it on there where is the eec relay

**mustang50lx** · 02-25-2009, 07:47 PM

Originally Posted by 90TitaniumStang

i did the module im sorry i thought i put it on there where is the eec relay

I can check at work tommorow at work. I think it is above or near the PCM, but I will check.

**DMmustangLX** · 02-25-2009, 07:37 PM

either the module itself is bad or it could be the fuel pump tony71502 on here had that same problem with his car u could try and pm c what he says. i know he changed the fuel pump and fuel filter. hasn't had a problem since

**DMmustangLX** · 02-25-2009, 07:38 PM

never mind on the module lol

**2001GTTT** · 02-25-2009, 07:51 PM

just throw a JAP motor in it.

**90TitaniumStang** · 02-25-2009, 08:49 PM

the fuel pressure is staying constant i just put a computer in it and it has run for 20 minutes no and hasn't shut off the eec relay isn't under the kick panel i took the dash loose even and its no where to be found

**coupeguy_black** · 02-25-2009, 08:59 PM

I have had the same problem...

fuel pump when get hot.

**coupeguy_black** · 02-25-2009, 09:00 PM

Originally Posted by 90TitaniumStang

the fuel pressure is staying constant i just put a computer in it and it has run for 20 minutes no and hasn't shut off the eec relay isn't under the kick panel i took the dash loose even and its no where to be found

relay is under driver seat that year

**silvernotch** · 02-25-2009, 09:13 PM

eec relay is up by the computer behind glove box. when that goes bad you get no spark,no fuel pump.I carry an extra one with me when I have the car out.Ya never know?

**Tony71502** · 02-26-2009, 12:14 PM

As DMmustangLX said, I'm willing to bet it's your fuel pump. The pump will operate normally until it overheats and then it will shut off... In which case you will have to wait a few minutes until it cools down and starts functioning normally again. The problem with fox fuel pumps is they rely on the fuel to cool the pump, so if you consistently run a low fuel level you will overheat the pump.