Car randomly dies, NO power Please help. THX

[mancuso4130]

Hi,

I have been researching this problem for awhile now and no fix. Its been getting worse. I have an 89 LX with some mods. Problem is I crank the car up, takes about 5 times and it starts up. Then start to move and will randomly die. Completely. All power, lights, everything is off. I turn key to off, then back to on, hear the fuel pump working, and lights, radio, a/c, etc come back on. Takes about another 5 times to start up. I've tried to let it warm up. still completely loses power and dies. While i'm driving, turning, backing up. Today, died 5 times on the way to church but drove home fine. I have researched everything here and to no avail. I have replaced with new distributor, with PIP and module. New coil, and fuel relay. but car still dies. Pulled codes and get 44 and 94 which are more related to vacuum/smog than car dieing. Had battery and alternater checked, they're fine. I really think its electrical, the way everything just dies, and have no power. Any suggestions? Please help as this is my daily driver and feel like i'm just a sitting duck when it dies out on the open road. Thanks, you guys are awesome.

 

[HISSIN50]

Are you losing items that are also on while the key is off (headlights for instance)?

If so, go over all your battery cables. The battery terminals themselves are the FIRST place to start. They can seem tight but have a layer of crap between them and the posts. Remove them, clean and reinstall them.

Also check the connections on the battery side of the starter solenoid (generally the firewall-side lug; the one with 10 pounds of wire attached to it). If this connection is bad, the car can lose all power.

Adding an extra motor ground is always a good idea. A 4 AWG cable is cheap and easy to install.

Random thoughts.
Good luck.

 

[jrichker]

If after following HISSIN50's advice you still have problems, try this when the car dies. Check to see if your headlights
work. If not, then you have some wiring problems in either the battery ground or the cable between the battery and
starter solenoid. Remember that the main battery chassis ground is a pigtail wire coming off the battery negative
terminal. It bolts down to the body at the place wher the screwdriver is pointing.

Picture courtesy timewarped1972

If the headlights do work ,then replace the ignition switch. It is a high failure rate part. Most auto parts stores have
them for $13-$15. Remember that you want to replace the electrical part of the switch and not the keylock mechanism.

Some electrical connections around the ighition switch to inspect while you are at it...

Diagram courtesy of Tmoss & Stang&2birds

See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host) for help on 88-95 wiring http://www.veryuseful.com/mustang/tech/engine/

Ignition switch wiring
http://www.veryuseful.com/mustang/tech/engine/images/IgnitionSwitchWiring.gif

Fuel pump, alternator, ignition & A/C wiring
http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif

Computer, actuator & sensor wiring
http://www.veryuseful.com/mustang/tech/engine/images/88-91_5.0_EEC_Wiring_Diagram.gif

Fuse panel layout
http://www.veryuseful.com/mustang/tech/engine/images/MustangFuseBox.gif

Vacuum routing
http://www.veryuseful.com/mustang/tech/engine/images/mustangFoxFordVacuumDiagram.jpg

 

[mancuso4130]

I have replaced the ignition switch about a year ago. I checked the top battery posts and are great. I will follow the connections and check those too. I am going grocery shopping soon, so will check the headlights when it dies. thanks

 

[jammer84_03]

check the module. both hissin and jrichker got the electrical wiring down. ive had the issue of the battery terminals being just a lil worn and it didnt have a good connection. new connectors and wires and i was on the road. random shut off like to say. module as well. runs fine then bam it dies. try hissins first and jrichker and if that fails check the module. how many miles on the car now? any recent mods to the electrical system or the engine being pulled / rebuilt?

 

[ninety15.0]

I would also take the pass side kick panel off and check the ground for the computer while you are searching for electrical issues. It would also be a good idea to take everything off the starter solenoid, clean the posts/connectors and put it back together. This will not only ensure that you have good connections there. But you will be able to closely inspect all the battery/ground connections while you are at it.

You're right it does sound electrical.

 

[jrichker]

I would also take the pass side kick panel off and check the ground for the computer while you are searching for electrical issues. It would also be a good idea to take everything off the starter solenoid, clean the posts/connectors and put it back together. This will not only ensure that you have good connections there. But you will be able to closely inspect all the battery/ground connections while you are at it.

You're right it does sound electrical.

The braided ground strap near the computer is the shield ground for the TFI module wiring.
It prevents the other electrical noise from messing up the TFI signal.

The actual computer power ground is two black/green wires that join to become one wire that exits
the wiring harness near the starter solenoid. It connects to a black cylinder about 2 1/2" long
by 1" diameter with a black/lt green wire.

 

[mancuso4130]

Found it YEAH

went to run errands this morning. The usually crank five times ordeal. with key in on position no power, then for some reason shook steering wheel and brief power then out again. did it several times. So I decided to take steering colum apart because there was no power, and seemed like too much play in steering wheel. Turns out both bolts were loose in steering column and ignition switch had started to come apart, where plastic meets the metal. Put new one in and TADAH, Alls well. Hope this helps someone in the future. Thanks for the Help.