ALWJ

I'm putting an 89 Mustang 5.0 into a 66 bronco and I'm not getting spark. I've had the motor running once, but apparently there is a difference between the automatic and manual starters. When the Starter blew up it created a short directly from the battery to the frame and burned up some of the bronco harness. The mustang harness was allright... I hope. I've heard the computers are really sensitive to ground and if the frame (ground) was 12V with a lot of current it might have hurt the computer. I've replaced the coil and TFI module and am debating whether to replace the distributor or the computer next. Is there a way to diagnose if the computer is faulty? Or anything else I should be looking at? Please share your expertise with a 5.0 novice

r.barn

I would read thru the info at following site and see if you can find some way to test the EEC
TONS of good info here
http://fordfuelinjection.com/

shaners90lxhatch

Computer does not control spark, just signal to module for spark advance. If you have inj pulse, the pip is still good and getting to the pcm. The PCM is not bad if spark is all you are missing.

ALWJ

PIP?

shaners90lxhatch

Profile Ignition Pickup (signal from the pick up coil or stator in the distributor)

P Zero

Id say try replace the disty mounted ignition module, and slap in a KNOWN GOOD COIL, that should take care of it.
-P.

ALWJ

Coil and ICM are both brand new remans as of yesterday... and I even tried a known good coil out of my buddies truck. So the PIP is what you test with the DC light tester to check for a flickering effect?

shaners90lxhatch

NO. you would want to check for the signal to the ignition coil. You will need a voltmeter and you want to check pin 56 of the PCM and at module. for 6 volts (its actually a switching 12v signal but the voltmeter will read it as 6 volts because it switches so fast. A test light will not pick up the signal from the stator. You likely have a wiring issue as if the ignition module is getting the pip, it should pulse the coil. So with that said, the module is either not getting the pip, or the coil is not getting the signal from the module.

I tried to copy and paste the wiring diagram but it won't work.

The pip wire is the grey and orange wire. You want 6v when cranking at both the module and the PCM. Use the test light (clamped to bettery positive) at the tan wire for the #1 fuel injector. This will be the frontmost injector on the passenger side. If the test light flashes when cranking, the PCM is getting pip and the module is not. Otherwise if you have no spark and no injector pulse - Niether the pcm or the module are getting the signal from the stator.

ALWJ

How many volts should the injectors see, and the voltage should be pulsing right? I bought a new distributor and I got spark... but only with the computer unplugged. As soon as I plug in the computer I loose spark. If I need a new computer does anyone have a good source for replacements? The local store wants about 130 bucks for a CA emissions computer... which isn't too bad, but I thought I would ask.

shaners90lxhatch

You may have a bad pcm if it is shorting the IDM or SPOUT inside of itselt. You want a pulsing ground to the injectors, and a steady load capable 12v power at all times. I will grab a wiring diagram when I get a chance and see what the odds are of you having a wiring issue. Only thing is that the PCM just modifies your spark timing, it does nothing else with the ignition system.....