Hey guys,

New to the forum, I'm very excited to have found you guys.

I've been trying to figure out what's been causing my no spark all week and I'm at a loss... I'm handy with mechanics but new to Fords and trucks in general, so I'm hoping you guys might be able to help offer some insight as to what could be wrong. Here goes:

86 f150 XLT Lariat, 5.0 fuel injected v8

I bought this truck last week, and it ran fine. Drove it home 30 miles, the next day it had some weird stalling issues at idle (something in the charging system is bad, and the battery kept dying, so i linked it to that), and I limped it through emissions. The battery totally crapped out on me on the way home, so I had the battery charged at Autozone, and went back later that day, put the battery in and she fired right up and drove home. The next morning I went out to start addressing the charging system, cranked the engine but it wouldn't start. I checked for spark first, and bingo- no spark.

This past week I've been working on it here and there, and here's now how the truck sits:

When i connect the spark wire from the coil to ground via a spark plug, it sparks a single time when i crank the engine, and then won't spark again as long as I continue cranking. If I return the key to RUN, and crank again, there's no spark. However, if I turn the key to OFF, then RUN then START again, I get another single spark, but only a single spark. It's a strong, healthy blue spark.

i tested the connector at the coil (from the ICM to the coil) with a test light and it's the same thing-- a single spark at first and then nothing else.

ICM is brand new

I tested the PIP sensor by the HAYNES manual and it checked out in spec(~7v during cranking), but then I checked it with the LED test found here:

Part 3 -Ford Ignition Module Test. Distributor Mounted Module (ICM).

and it failed- the LED would blink once and stay dimly lit during the rest of cranking.

also worth noting- according to the HAYNES manual, it failed the SPOUT signal test-- at which point the manual says it means the "PCM is most likely bad, but you should bring it to the dealership so that they can switch modules and test and so that you don't have to pay to buy another one."

From what I understand though, the SPOUT signal has nothing to do with a no spark condition though... it only affects the spark while the engine is performing, correct?

Does that single spark indicate anything to you guys? I'm thinking of replacing the entire distributor (replacing just the PIP sensor seems like a HUGE pain, especially as I only have basic hand tools and no bench vise just moved and had to leave shop behind) but I would hate to go through that expense and time if it won't fix the problem.

Do you guys have any thoughts? I'm very close to hitting a wall on this one.

Many thanks,

Kyle

 

If you pull the codes from the computer, it should give you spout and other error codes if it doesn't see those signals. If the computer won't talk to you, you might have a ground problem or a power problem to the computer.

Go over to the battery and look for a smaller wire coming off the negative terminal. It should have a connector in it, and then it goes into the harness. Check this out, it's the main ground for the computer, and it likes to get corroded over there next to the battery.

 

Great thanks Franklin2. I'll check that wire this afternoon.

But the spout signal has nothing to do with it getting spark, correct? It's just a spark advance signal? The truck shouldn't run fine (not perfectly under acceleration) without it, right? This would point to the PIP sensor being the culprit, right?

Lazy question--

If the PCM was bad, would the truck still run okay?

 

The PCM monitors the spout and the PIP. I would see what it had to say.

 

I am having the same issue with my 86 F150 w/ 5.0 302. The wiring on the truck doesn't look right and I want to make sure I before I change my ignition control module. From my wire harness I have 2 yellow w/green stripe (both getting 12v when the ignition key is on) and a green wire. My connector has 2 green wires at the negative and 1 red at the possitive. I saw a picture on American muscle that they switched the green wires to the possitive and the red to the negative. The red is now connected to the green from the harness and the greens are connected to the yellows. So now I'm getting 12v on the possitive.
Does this sound right? I want those wires to be correct.

 

Beware!!


Ford did some stupid wiring on the ignition modules. All of mine have connectors with white and red wires. It seems like red would go to red and white to white, but it doesn't and if you wire it to what "looks" correct it will not run.


As far as the one spark goes, does it spark at the end when you let off of the key or as soon as you to the start position?