Guys,

I've got a really frustrating problem with my 1996 F150 5.0. It only sparks on crank about every 20th attempt - then dies abrubtly shortly thereafter. It has a new coil and ICM, so these are not the problem. The PIP signal from the distrubutor looks OK, though the AC cycles above that spec listed in the Haynes??? There is not a SPOUT signal during crank. I have a P0320 code - Ignition/Distributor Engine Speed Input Circuit. I've tested the harness and can't find any opens or shorts yet, though I don't know the SPOUT pin on the ECM connector. The Haynes sucks for 1996 ECM because of the OBD II - I've ordered a second hand set of factory service manuals. I could use a bit of advice from experience at this point.

- Should I replace the PIP sensor preemptively even though this is starting to seem like a bad ECM?
- Where's the ECM in the cab?
- What's the SPOUT pin on the ECM connector?
- Is there a procedure for replacing the ECM?
- Any other troubleshooting advice? Known problem connections to test?

Thanks,

Andy

 

I would be curious to how you check the PIP signal, did you use a scope?
Unplug the SPOUT shorting bar and then check to see if you have spark and if it will start.
Unplug the SPOUT first.
Should be in the drivers kick panel but you get to it from under the hood.
Pin #50
Move the inter fender out of the way, un-hook the battery, loosen the bolt on the PCM plug (10mm). Then take it out.

Take a test light and see if you have power on both sides of the coil.
If none on the TACH side check and replace the coil connector plug.
If power on both sides see if the TACH side flashes while you crank the engine.
Let us know what you find but I bet it is the coil plug.

 

subford, thanks for advice.

No, just looked at AC voltage on a multimeter.

Same behavior. Mostly just cranks but won't start. Occasionally it will start and run for 5 sec and then die.

I'll try this again tommorrow, but I have datapoints on the TACH signal that say when it starts I can see the test light flashing on crank, but when it won't start the light just stays on.

 

Do the mass air flow trucks still have an ignition control module? That or maybe even just a faulty Crankshaft Postioning Sensor if it has one. Not quite sure just tossing some ideas out there.

 

I replaced the ICM to no avail and there is only the PIP sensor on the distributor - no CPS. Thx.

 

I've attached some pics of the ECM location to help you out in case you didn't know where it was.

ECM is the one on the right:



Here's a Closer Image:



Hope this helps....

JR

 

its the ignition module.....around 80bucks in canada .....

 

Thanks guys. Is there an ECM cross-reference somewhere? Are A/T and manual ECMs incompatible? I'm not ready to swap it yet but I'm gonna keep my eye out for one if its a rare bird (302/5speed).

 

OK here's an update on this mess:

I got the factory manuals which clarify the wiring. I confirmed good ground for distributor, ICM and PCM, including PCM to distributor. All voltage sources to ICM, PCM, distributor and coil are good. PIP signal lines from distributor to PCM and ICM < 1 ohm. SPOUT signal line from PCM to ICM < 1 ohm. PIP sensor is producing an AC signal, but I can't tell if its any good with my crappy multimeter. There is no signal to the coil primary - just solid 12v when starting. The test light doesn't flash. This is with NEW ICM and coil.

At this point I took a guess and sourced a second PCM for $115. Didn't fix the problem.

Unless (a) I'm missing something (b) have some bad data, or (c) one of my replacement parts is bad the only thing that remains is the PIP sender.

I disassembled the distributor tonight and I'm going to try and source the PIP unit from Ford tommorrow. Is there a separate part for this from the factory?

This is getting really frustrating. I'm about to trade it for an old flathead. Any advice appreciated.

Andy

 

chances of a new part being bad...slim....

 

If you are asking if you can just buy the PIP sensor then the answer is yes.

Sounds to me that you have a bad plug that plugs onto the Ignition Coil.

 

Having a new part be bad is very slim but not unheard of.....Listen to Bill....he knows what he's talking about......

www.directfordparts.com

JR

 

Victory at last.

It was the pickup coil (PIP unit), which is, of course, the most painful part to replace in the ignition system. Truck is running fine now. I feel like a dumb a&$ having a spare PCM, coil, ICM and a full set of factory service manuals but I'm sure they'll come in handy someday. Time for a victory beer...

One thing I'm thinking about acquiring as a result of this episode is a graphing multimeter of some sort. If I could have viewed the PIP signal trace I'm pretty sure I would have figured this one out a lot more quickly and avoided the part shotgunning.

Thanks all for the advice! Andy

 

digital graphing meter will never be a bad purchase.....

 

Glad you think so...cause I have no idea what it is lol.

JR