91 Mustang LX 2.3 Tachometer died and rear coil dead

[Scottoldboy]

The tach quit working on daughter's `91 2.3l Mustang. (dual ignition) Rear coil pack is not functioning. Swapped coil pack positions and car ran roughly on the now front coil. The good coil moved to the rear position didn't function and the tach still didn't work. Swapped coils back to original position and engine ran smootly on front coil again. Rear coild is leaking something. Rear coil pack will be replaced, but it doesn't appear to be getting a signal as when the good coil was put in the rear position it didn't function.

[flstang]

Originally Posted by Scottoldboy

The tach quit working on daughter's `91 2.3l Mustang. (dual ignition) Rear coil pack is not functioning. Swapped coil pack positions and car ran roughly on the now front coil. The good coil moved to the rear position didn't function and the tach still didn't work. Swapped coils back to original position and engine ran smootly on front coil again. Rear coild is leaking something. Rear coil pack will be replaced, but it doesn't appear to be getting a signal as when the good coil was put in the rear position it didn't function.

I am having the same problem on my 92. I had 2 codes come up 223 & 224. 224 is a DIS module which is cutting signal to your primary coil(which is your back one). When i replaced my dis, car ran fine til the dpi (223) keeps going into limp mode ( tach drops a grand while drive and idles at 500 & check engine light comes on, both codes will cause that only thing you can do with that is shut the car down and restart-reset itself) . Im tryin to run that problem down. (hoping it isnt my computer)
DIS module is located on the intake manifold w/2 connectors going into it. They are not cheap- napa my cost as a mechanic was $185 list around $225 thru ford my cost $336 list price $425. You choose wisely. lol.
I hope you replace the dis and not run into my problem too. Good Luck.

[mastermech]

the tach gets the signal from the ignition module that is on the idm circuit that goes to the pcm.

[Scottoldboy]

Originally Posted by flstang

I am having the same problem on my 92. I had 2 codes come up 223 & 224. 224 is a DIS module which is cutting signal to your primary coil(which is your back one). When i replaced my dis, car ran fine til the dpi (223) keeps going into limp mode ( tach drops a grand while drive and idles at 500 & check engine light comes on, both codes will cause that only thing you can do with that is shut the car down and restart-reset itself) . Im tryin to run that problem down. (hoping it isnt my computer)
DIS module is located on the intake manifold w/2 connectors going into it. They are not cheap- napa my cost as a mechanic was $185 list around $225 thru ford my cost $336 list price $425. You choose wisely. lol.
I hope you replace the dis and not run into my problem too. Good Luck.

Thanks for the reply. Somebody told me the tach signal came from the primary coil but I didn't know which one it is. I suspected the DIS module. The bad coil probably toasted it. The tach was dipping as you said just before it died all together. Wanted to hear what the voices of experience had to say.

[mastermech]

Originally Posted by Scottoldboy

Thanks for the reply. Somebody told me the tach signal came from the primary coil but I didn't know which one it is. I suspected the DIS module. The bad coil probably toasted it. The tach was dipping as you said just before it died all together. Wanted to hear what the voices of experience had to say.

Here's some info that might help. The red/lt grn wire is 12+ when the key is in run. tan\white and tan\org come from the pcm to the primary coil. And tan/lt grn and tan\lt blue run from the pcm to secondary coil. Take the module and have it tested at an autoparts store. As I said earlier the signal for the tach comes from the module.

[Mustang Mike]

I am having a similar problem with my '93 2.3 leter. Accept with mine the tach. is reading half of the correct RPM. So when the engine is running 3 grand the tach. says 1.5. Every onnce in a while, the tach will read correct and the "check engine" light will turn off. Otherwise it stays on all the time. The engine runs great accept occasionaly stalling from a stop. At which time you have to crank the ignition repetedely before it starts. This may be a related problem. Any more advice would be greatly appreciated.

[lxstang]

i'm having issues with the tach on my 91 2.3l mustang it runs fine except when the tach decides it wants to try and work then it idles rough and dies more often than not and can't be started right away. and on occasion when i try to start it it'll make a single poping noise like it's backfiring or something can i get a few tips on what to try to get this issue fixed.