1989 F-150 4.9L No Spark!

Hi,
No, I had a signal on the PIP and then I didn't.

Thats when I said to hec with it and rebuilt the old dizzy with new MOTORCRAFT parts!

I will have to start over with the testing but want to pursue this RF noise capacitor theory for a bit?

I believe everything is good but something in the wiring, somewhere, is keeping the coil from sparking??????

Thanks everyone!!!

I believe everything is good but something in the wiring, somewhere, is keeping the coil from sparking??????

I went over the thread, so forgive me if someone suggest this already. :blush: Will a test light connected to B+ pulse when touching the dark green/yellow wire at the coil? This indicates if the ICM is controlling the coil or not.

I will have to start over with the testing but want to pursue this RF noise capacitor theory for a bit?

Please do! Pursue it until you're confident. But, I can tell you from experience that the capacitor is not required for spark to occur.

yep tyler i suggested that seeing what was missing at the coil power or control.... wanted to try a bypass test using a testlight connected to battery negative touching the control wire on and off see if the coil sparks.... you know as much as i do new means nothing.... new is as good as the new snap on scanner not very good!... qc these days

cheryl hartkorn wrote: yep tyler i suggested that seeing what was missing at the coil power or control....

My bad! :blush: I figured someone went down the same path before me. Musta skipped over it...

you know as much as i do new means nothing.... new is as good as the new snap on scanner not very good!... qc these days

Truth.com right here. What's the acronym? Never Ever Worked? :lol:

Hi,
Ok, I think I made some progress today!

I did not get it to start but....

Checked out the capacator and there was some insulation missing on it, taped it up.

It has a connector and it looked good.

Ok the coil connector was holding the spades lose or not at all so I put in a new one.

Had the battery charging all day so it was fresh, tried to start but no go.

set up the hand switch and the test light connected to negative and pulled an air gap on the coil tower.

Cranked it up and got a nice strong white spark with a 3/8" gap?

Ok, I'm feeling good, put the coil wire for the dizzy on and tested that, same thing nice spark!

Put everything back went into the cab expecting a start and nothing?

Went back to the coil tower and hand switch and NOW the coil is stone dead nothing???

Sooooooo........I'm thinking now EEC?

Oh yea, I tested pwer on run and everything comes up. headlights, guages idiot lights, radio.

So that is where I am at, thanks for any thoughts on this!!!

Hi,
Well...I was told on another forum that the computer has nothing to do with the ignition system creating spark per se???

I noticed when I put in the new ignition coil connecter, that the installer for my aftermarket cruise control (10 years ago!) spliced in a power wire (soldered) to my 12V ignition coil wire???

I left it alone but wondering now if it could be the cause of the trouble?

Think I will cut it and get it out of the equation, just trying to simplify a perplexing problem?

So...I guess I'm going to cut that wire and pull and clean all the grounds I can find and probably do the same testing over again?

I don't know what else to do?

Any ideas on this are appreciated!

Does ScannerDanner ever come on his own forum???

seagiant wrote: Hi,
Ok, I think I made some progress today!

I did not get it to start but....

Checked out the capacator and there was some insulation missing on it, taped it up.

It has a connector and it looked good.

Ok the coil connector was holding the spades lose or not at all so I put in a new one.

Had the battery charging all day so it was fresh, tried to start but no go.

set up the hand switch and the test light connected to negative and pulled an air gap on the coil tower.

Cranked it up and got a nice strong white spark with a 3/8" gap?

Ok, I'm feeling good, put the coil wire for the dizzy on and tested that, same thing nice spark!

Put everything back went into the cab expecting a start and nothing?

Went back to the coil tower and hand switch and NOW the coil is stone dead nothing???

Sooooooo........I'm thinking now EEC?

Oh yea, I tested pwer on run and everything comes up. headlights, guages idiot lights, radio.

So that is where I am at, thanks for any thoughts on this!!!

Well, that's progress! Mostly, I'd be interested to know if the PIP signal is present at the ICM when you're getting spark, and when you're not getting spark.

A DMM will work. Per one of SD's videos, we're looking for four to five volts on the PIP wire at the ICM during cranking. Referring to this video:



The PIP wire is the dark blue wire at the ICM.

For me, it's important to know what that PIP signal is doing both when spark IS occurring, and when spark is NOT occurring. If signal is present during spark, but not when you lose spark, then we're going towards the Hall effect sensor and its wiring. If signal is present there in both cases, then we're going towards the ICM and its wiring.

Let me know if you have questions about this test or how to set it up, and I can help you further.

Hi,
Thanks Tyler!!!
I've already watched all the SD Vids that pertain to my system.

I have to work this weekend so it will be Monday before I can get back to this.

I know how to test the ICM by back probing with "T" pins and I made a small LED light to test with but it stopped working also?

I have a good FLUKE meter and the last time I tested the PIP wire got about 5.0V

I guess I would have to get a spark tester hooked up and the VOM Meter at the same time to see if the coil is sparking during a test plus start the engine?

I'm by myself in a parking lot trying to do this so may not have enough hands?

Thanks for the help, I do appreciate it!

Have you seen the EEC IV series I have on my premium channel?
Hopefully these links will take you to them once you subscribe.

Ford EEC IV no spark troubleshooting part 1
www.scannerdanner.com/scannerdanner-prem...shooting-part-1.html

Ford EEC IV no spark troubleshooting part 2
www.scannerdanner.com/scannerdanner-prem...shooting-part-2.html

Ford EEC IV no spark troubleshooting part 3
www.scannerdanner.com/scannerdanner-prem...shooting-part-3.html

seagiant wrote: I've already watched all the SD Vids that pertain to my system.

I have to work this weekend so it will be Monday before I can get back to this.

I figured you'd seen these, just threw that in there for anyone else following along. I'll check back in Monday.

I know how to test the ICM by back probing with "T" pins and I made a small LED light to test with but it stopped working also?

I have a good FLUKE meter and the last time I tested the PIP wire got about 5.0V

Sorry about your LED light. That 5V number sounds good working signal to me. As an alternative to the voltage test, if your Fluke will measure frequency, you can look for 12 to 16 Hz during cranking. I also recall that you can measure this signal for duty cycle. Should be between 47 and 53%.

I guess I would have to get a spark tester hooked up and the VOM Meter at the same time to see if the coil is sparking during a test plus start the engine?

I'm by myself in a parking lot trying to do this so may not have enough hands?

Yeah, sorry about that, not trying to run you ragged. :lol: One of these Thexton testers is my weapon of choice, if you don't have one already.

Hi,
Thanks Tyler!!!

I just ordered that spark tester you linked!

I have another type at home but doing me no good here.

I have a remote switch to turn over the engine so might be able to run that test.

I'm going to go back Monday and run more continuity test on the wiring that goes from the ignition coil to the ICM.

SOMETHING has to be stopping the signal from getting to the coil????

I hate to split the harness to trace back to the ICM but might have to?

I'll do all the test again but as I said almost EVERYTHING is NEW MOTORCRAFT
now!

Nice! I think you'll be happy with that spark tester. You can also combine it with jumper wires as needed to get the tester where it's visible.

Because spark is coming and going, I'm wondering if there's a weak power or ground to the I'm, causing intermittent operation. We can dig into that more once we know what's happening with the PIP wire during cranking.

Hi,
Thanks, can I get the info I need from just the VOM or do I need the little LED light again?

Was actually thinking of getting a Snap On MT 2400 but they are so old now worrying about having to fix THAT!!!

I guess I'll try the Spark Tester/VOM set up, I do have a Hz function!

Hi,
Well.....I just bought a Power Probe 3.....

My test light sucks, so I thought why not crank it up a few notches!

I'm going to find out what is going on with these wires one way or the other!

Man you are DETERMINED. :lol: I love it.

I think you'll like that PP3 - I've had mine for about five years now, handy for all kinds of stuff. Just be careful with that rocker switch. The temptation to switch power or ground to circuits is very strong.

If you're looking for a scope, the uScope is out there, and reasonably priced. This is the newest kit from AESwave:

www.aeswave.com/uScope-with-Test-Lead-p9493.html

I dunno how deep you want to go down this equipment rabbit hole. But a used first-gen Modis would get you a scope PLUS access to the Ford KOEO and KOER codes, if you can find one with the OBD-1 adapters.

Hi,
Thanks Tyler!

With the OBD-1 on the old truck, I don't know how good these sophisticated scopes would be?

Admittedly I bought the PP3 because I think I will have wiring problems in other places besides the ignition system.

I'm sure I'll be glad I bought it as it will help with small motor and fan work also.

I'll probably just go with this for now but will keep an eye out for the MODIS!

seagiant wrote: With the OBD-1 on the old truck, I don't know how good these sophisticated scopes would be?

Very useful! In my experience, anyway.

This is an example of a PIP signal I took off an early 90's F-150 last week. The glitch is obvious when looking at it this way, but I'm pretty sure a DVOM would have struggled to catch it:



The scope also opens up secondary ignition and current probe testing. Again, off that same F-150, the current ramp for one of the injector drivers. This waveform made the cause of the running issue clear as day for me:



I'm NOT saying you need one to fix your truck. I just find that it helps me understand what's happening in a circuit.

Hi,
Thanks for that!

I'm going to run the tests from my Haynes Manual and write everything down with results!

I actually suspect the signal wire in the harness from the ICM harness to the ignition coil harness?

But, I will start over and see what I come up with, I'm hoping that the PP3 will let me know how solid the continuity is, on the wires I test, BETTER, than the VOM meter???

Supposedly the red green lights for power and ground will flicker or sound broken if the wire is "iffy"!

I believe the parts are good but there is a problem or short somewhere?

This would of been done a week or more ago, if it was just a bad part!

Thanks again!

if your still worried about the continuity of the wire i say use a headlamp bulb to load those 2 wires. much more of a load than a simple continuity test in my opinion

cheryl hartkorn wrote: if your still worried about the continuity of the wire i say use a headlamp bulb to load those 2 wires. much more of a load than a simple continuity test in my opinion

Hi,
Anymore info on that???

A link maybe?

Everytime I "Goggle" head lamp, it gets changed to head light!!!