Friday, June 19, 2015

94 Mustang GT: Distributor Swap / Upgrade

On the way home last week car was stumbling.  About a block from home, it finally died.  My wife jumped in our expedition and came to the rescue.  We dragged the 94 home the rest of the way.  I would be cranking it when making turns so that the PS pump would run.

When we got it back to the house, I did some checking.  I have the original stock coil that is known good.  I swapped that and still no start.  I also have a known good foxbody distributor with the TFI on the side of it.  I stuffed that down in the fenderwell and unplugged the TFI, plugged it into the fox distributor - still no start.  Next I unplugged the coil wire from the distributor and put a spark plug in there.  While holding it against the engine (ground) I had someone crank it and it just didn't seem right to me.  There was a 1-2 second pause in between sparks.  The coil should be sparking way more than that.  At this point I suspected the PIP sensor in the distributor.

After doing some research about replacing the PIP in the stock distributor, I realized that it would turn into a complete rebuild of the stock distributor.  After feeling how much play is in the stock distributor shaft I was convinced it would need an overhaul.  At some point I will rebuild it to keep as a spare.  Stay tuned for that!

I wound up going with a summit street / strip distributor.
http://www.summitracing.com/parts/SUM-850410

I've heard good things about the mallory and MSD and this summit distributor was almost half the price.  Also, my 94 is basically stock motor (for now).

The new distributor showed up yesterday.  Here is the removal:

I took the time to chalk the marking on the balancer so I could see them better.  I used the 15/16 socket, short extension and rachet to turn the motor over until the timing pointer was at 0* / TDC.  I made sure that the distributor rotor was at the #1 cylinder, and noted the orientation of the distributor harness.  Then I pulled coil wire off the cap and unlatched the cap.  I removed the distributor hold down, unplugged the harness and removed the harness from the bracket it was mounted to.  Then I held the cap (with all the wires still attached) out of the way and pulled the distributor out.

Installation:

Still holding the cap and wires out of the way, I installed the new distributor so that the orientation of the distributor harness was the same.  I also made sure that the rotor was pointed to the #1 plug wire (rotor turns clockwise as the distributor gear and cam gear align).  I installed the hold down and plugged in the harness.  I then put the old cap on the new distributor, and installed the coil wire.  I jumped in the car and it started right up!  I shut it off.  Next I transferred the wires from the old cap to the new cap, one by one, and latched the new cap and wires to the new distributor.  I pulled the spout connector out of the harness on the passenger side fender.  I set up the timing light and started it up.  It was running really rough!  While setting the timing, I realized it was way off.  The distributor wiring harness was not in the same position as the stock one once I found 10* BTDC.  At this point I realized I was 1 tooth off on the distributor.  It ran just fine, but it had to come out for me to be able to sleep at night.  I shut the car down, set the balancer at 0*, pulled the cap, pulled the distributor hold down, unplugged the harness and slowly lifted the distributor up with one hand on the rotor.  I kept pressure on the rotor (to the left) until it was free of the cam gear, then I moved it one tooth over and pushed it back down again.  It never even came fully out of the engine.  I plugged it back in, installed the cap and hold down and started it up.  Perfect!  I set the timing at 10* and it was all set.

I took it for a ride.  The throttle response is noticeably more sharp!  I still need to take it out a few more times.  The car is alive again and with a little bit of an upgrade!

Notes:

That stock distributor and PIP sensor lasted 21 years and 237k miles!!
Ignition setup:  Moroso Ultra 40 race wires, autolite#24 plugs, Mallory 29214 coil, and a stock foxbody motorcraft TFI modified to fit.

Thoughts:

1.  I may pick up the dyna mod TFI to see if that offers anything else.  If for nothing else I can keep that motorcraft TFI as a spare.

2.  I will rebuild the stock distributor and do a write up on that.  It will be a rainy day project!



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