The Ignition system is one of the most overlooked & under-appreciated systems on a Fox Mustang. From the factory the stock system was quite capable & reliable. There are still many a fast Mustang out there running stock style distributors, wires, plugs, and coils; however, as with most systems, there is room for improvement. Especially when you are faced with component replacement because of failure.
Yes, we just mentioned failure on a system we just referred to as reliable. Everything fails. Time and use take their toll on everything. The 1986-1993 Mustang Ignition System failure that you are likely most familiar with is TFI Module (Thick Film Ignition) failure. This typically presents itself at the most inopportune time, when your Fox Body Stang is at operating temperature, the engine will just die. After a short cool down period, the engine will most of the time restart, go down the road a little way, & then die again once the heat builds up. When these symptoms first presented years ago, it was easy to "trend fix" by simply replacing the TFI Module. Now that the 86-93 Ponies have quite a bit more age under her thier belt, "trend fixing" these symptoms is not as easy. The reason is that the PIP Sensor (Profile Ignition Pickup), also called a hall effect sensor, presents the exact same symptoms when it fails. The problem is that the PIP sensor requires the distributor to be completely disassembled to be replaced. Not nearly as easy as the TFI module!
The next consideration is the amount of wear your distributor is presenting. If you don't know the mileage on the current one, or if you know yours has high miles, then the shaft & shaft bushing are probably worn to the point of having noticeable slack between them. This causes erratic spark timing and in severe cases can even cause "spark scatter". This is starting to sound like quite a bit of work to fix the problem, right? Not Really.
Companies like Performance Distributors Inc. (PDI) make it quite a bit easier by offering a complete replacement drop-in distributor for your 1986-1993 Stang. Take the Hot Forged Distributor for instance. PDI starts with a CNC Machined forged aluminum housing. Then they press in an oil-impregnated bronze bushing, add a high quality PIP sensor, slide in the steel shaft, and press on a steel drive gear that is fully compatible with roller camshafts. They top it off with a cap & rotor that feature brass terminals for the best conductivity possible. The real brains of the Hot Forged Distributor is the Dyna-Mod TFI Ignition Module
. It allows for a longer coil saturation time which provides a longer duration spark. This smooths out idle and revs, offers more complete combustion, as well as improving fuel economy.
Now that you know why you need to replace your distributor, lets cover the how. Start by disconnecting your battery. It is a good "best practice" to clean around the distributor where it enters the block so no dirt or debris fall in the engine once the old one is removed. Remove the distributor cap by releasing the two spring clips. Make note of the direction the rotor is pointing as well as the orientation of the TFI module. Unplug the TFI module connector. Grab you a specialty distributor wrench or a 1/4" ratchet, long extension, swivel joint, and a 1/2" socket to remove the distributor hold down bolt and clamp. Lift the distributor out of the engine.
To install your new distributor, start by lubricating the camshaft gear along with the gear. Engine oil will work, but PDI includes a specialty camshaft lubricant for this purpose. Slide the distributor in to the engine, aligning the rotor & TFI module at the previously noted positions, and fully seat the distributor in the block. Re-install and tighten down the hold down and bolt. Plug in the TFI module connector. Transfer the spark plug wires to the new distributor cap. The 1986-93 Mustang 5.0L Firing Order is 1-3-7-2-6-5-4-8. Cylinder #1 is typically marked on the distributor cap. If not, it is the terminal closest to the intake manifold. If you are also installing new wires, cylinders 1 thru 4 are on the RH passenger side of the engine. Cylinders 5 thru 8 are on the LH driver side of the engine.
Start the car & verify timing! I can't stress this point enough - Any time you touch the distributor you need to verify ignition timing!
Check out How to Set 5.0L Mustang Ignition Timing
for instructions on how to check & adjust your timing.
When installing a new distributor, it is a great opportunity to go ahead & freshen up the rest of your ignition system as well. New Spark Plugs, Spark Plug Wires, and ignition Coil will complete your system transformation. We offer the parts individually, as well as the 1986-1993 Mustang 5.0L High Performance Ignition Kit. Don't ignore your ignition any longer - Upgrade & improve today!