Car Suddenly Dies!

Discussion in 'Fox 5.0 Mustang Tech' started by aprost27, Nov 6, 2012.

  1. Hi everyone, I'm new here and hope someone can help me out? I have a 1990 lx notchback and recently the car has been dying on me randomly. I'll be driving along just cruising under light load, barely pushing the gas pedal and ill come to a stop like a red light and suddenly with no warning it will just die, no rise or fall of RPM's, no check engine lights, NOTHING! Sometimes it will start right back up and sometimes i have to wait a while sometimes even up to about an hour before it starts back up. ive noticed that even after i get home from driving around for a while with no problems, ill shut the car down go in the house for a long while go to start it up and nothing. it will crank over but will not fire up.Things I've done to try and solve the problem are as follows.....(changed the fuel pump because I had to, not part of the problem) changed spark plugs,cap and rotor,did the TFI Relocation kit mod, upgraded to a DYNA ignition module, and replaced the coil. My next thing to replace will be the fuel pressure regulator. Right now I have a Aeromotive fuel pressure regulator but I'm going back to stock. My thought is that there is a hole in the diaphragm in my current fuel pressure reg. after this I don't know what else it could be...anyone have any thoughts???? Thanks in advance....
  2. Thanks "jcgafford", couple of things... is this a two man operation? i dont have any test lights or code readers, i do have jumpers and im a little confused on the part of the test in step #1 where it says to "jumper the screw to the big bolt on the starter solenoid that has the battery connected to it. what screw is it exactly? Is this procedure different than taking the car to a mechanic and him clearing all the codes?? im not with the car at the moment so thats why im confused about the first step. thanks for your help....

  3. i had the same problem with that one. seems like a two man job. your car does run so we know it does get spark, at least most of the time. till jrichker can chime in move past that step. clearing codes does not solve the problem. use the wire method and just run the codes and write them down. post them here so that help can be rendered. without dumping the codes first you are just wasting your time and money. jrichker
  4. Is there a way to just dump/erase the codes without doing all these checks? My car runs, has spark, fuel flow etc. it seems as though this test is for a car that doesn't want to start. Would you have any pictures to show step by step how to jump the connectors?
  5. Jumping the solenoid is to make sure the car cranks over. If your car cranks, don't jump the solenoid.
  6. Oh my bad, jumping the solenoid is only part of that test. I thought you were just trying to make sure the car turned over.

    On the solenoid there's a little push on connector up toward the top of the solenoid. It'll have a black end, and it'll be a red with a blue tracer. All you have to do is take something metal and contact that little stud to the positive stud on the solenoid. That's how you jump it.

    And I would definitely test everything in the Cranks OK, but no start check list, because you did describe some cranking/no starting conditions.
  7. pulling codes may tell you where the problem is with the poor dependability. easy to do, pull them. erasing the codes is as easy as unhooking the battery for 10 minutes, but that does not fix anything.
  8. Thanks guys, I'm gonna change the fuel pressure regulator and change out the computer... I have a spare one from a perfectly good running car and see what happens. I ran it yesterday, started right up the first try, idled it for about 5 mins. Gave it a couple of throttle blips, shut it down for about 10 mins. Went to start it up again and all it would do is crank over no seems as though there is some sort of vapor lock in the fuel sys.(just my thoughts) but don't really know if that's even possible. Thx again for the help....
  9. I don't think an EFI system can vapor lock.
  10. thats a lot more work than just pulling codes. pulling codes will give you a "11" (system checks ok) which when my computer went bad it would not spit that code. to each his own i guess
  11. 88lx5.0h and jcgafford thx for your comments, honestly I didn't think it would vapor lock. So I went ahead and changed out the fuel pressure regulator(your right jcgafford, a lot of work) still have the same problem. Shut the car down for about an hour and wouldn't start back up, had to let it sit a while longer and then it started then after driving for about ten miles stopped and let it idle for about 3-5 mins. And it shut off, started back up after about 10 mins. I haven't changed the computer yet because I don't want to damage a perfectly good computer. This Sh-t is getting old!!! I'm running out of ideas....thx again for your input.
  12. When the car won't start, do the checklist...

    You can dump the codes independently of anything else that you may be doing, and at anytime you can access the test connector while the car isn't in motion.

    When the car dies, does the radio, wipers or turn signals do strange things?, If so the ignition switch is the problem.
  13. I actually had a coworker with the same problem, i told him to repl his computer, and problem solved, would get hot inside and a diode or something would come loose, and boom, cuts off, than no start till it would cool off. Good Luck
  14. change the tfi module,thats what mine did if not it was only 50 bucks. it gets hot and shuts the car down then cools and runs like nothing happened.
  15. Thx everyone for your suggestions. I changed everything fuel press reg. some fuel related relays, did the TFI relocation kit and upgraded the TFI MODULE. Anyway, long story ended up being the distributor! Never changed the cmptr. So word of advice if anyone's car dies suddenly "check the distributor" hope this helps other people.