1989 F-150 4.9L No Spark!

Hi,
I have a FORD 1989 F-150 4.9L pick up.

The truck just died and will not start.

Using test procedures from Haynes and the Internet I first tested the spark from the coil tower with my test light and there is no spark.

I made a 12V led light to test the signal on the ICM after testing for power and ground at the connector, all was good!

Oh yes I tested the computer relay also and put in a new one.

Trying to not leave anything out.

When the ICM showed good I just bought a new MOTORCRAFT Ignition coil and put it in. (the old one had 300,000 miles on it!)

Put in the new ignition coil and sometimes I get spark sometimes not?

Checked the signal wire from ICM to IC and it has continuity?

Everything should be good but I'm now at a loss on what to do next???

Any ideas on where to go next would be appreciated!!!

are you getting 12 volts at one of the coil wires? check it under a load. id start there.

Hi,
Thanks!

I just started completely over in my testing.

Checked the IC for power and it is good.

Then checked it for a pulse signal and there was none.

Went to the ICM....ground and power is good, but...

Now no PIP Signal !

pulled the spout and engine does not crank.

This is confussing as I had the PIP signal before, but???

I'm going to see if I can rebuild a OEM ford dizzy with new MOTORCRAFT PIP sensor and ICM.

The dizzy in it now is a OEM junkyard find and worked for awhile I guess.

I don't know what else to try, need to get this going!

Hi,
Just finished rebuilding a JY FORD OEM dizzy, with new MOTORCRAFT PIP Sensor and ICM!

Try to get it in tomorrow and see if that makes a difference? (see if I can get a spark at coil tower???)

I have tried to test going by established guide lines, including watch ScannerDanner on U-Tube!

In this adventure though, the Cap and Rotor, now Dizzy rebuilt and the Ignition coil is new!

This truck has close to 300,000 miles on it so I'm not overly worried about buying parts, but would like to know something is bad before hand, if possible?

Hi,
Well, not a lot of feed back here???

Thought this would be the place to get some troubleshooting advice???

been busy with work. you said you put a new cap/rotor and distributor in with the module is new and still no spark??

Hi,
No, rebuilt it last night, all good there.

Will get it in today hopefully but worried if still no spark after that....

Where to go next?

This is a weird situation cause it seems that the ICM actually tested good then replaced coil as per troubleshooting guide....

Then ICM retested and now testing bad?

I don't know, wondering about the EEC/computer?

Guess I could pull it and look for bad caps?

Not getting a lot of help on this except other people on other forums giving their guess on what part to change which is not what I'm looking for!

I can do that on my own!

I'll put in the new rebuilt dizzy and see what happens!

Hi,
Put in the new rebuilt dizzy and got nothing?

I retested the coil, I got power on the positive and no flashing on the signal.

I did an ohm's test on the signal wire from the coil to the #5 signal coil ICM terminal and have continuity???

I back probed the #5 on the ICM and got 5 volts on my vom meter while cranking?

This is all GOOD by the test but I have no spark at the brand new coil?

My battery is now dead from the testing and I'm recharging it.

Oh yea, all of this is going on in a parking lot where I work so I'm having a ball!

If ANYONE here has any ideas, I'm all ears!

Probably pull the computer next as this is not going well by the book of testing and finding solutions!

could try tapping the signal wire to the coil to ground see if it sparks.

NEW means nothing

have you seen this article??

easyautodiagnostics.com/ford/4.9L-5.0L-5...ition-module-tests-5

i would definetly check the pip sensor. i havent messed with one of these in 15 years or so

cheryl hartkorn wrote: could try tapping the signal wire to the coil to ground see if it sparks.

Hi,
So, I understand the ICM gives the ground to the ignition coil off and on from the PIP Sensor, to make the coil "spark"?

If grounding that line at the coil, makes the coil spark then there HAS TO BE a short in that wire even if I get continuity???

Thanks for the help!

I do appreciate it, but I'm now a little aggravated with this!
'
I don't think any thing was wrong with the JY Ford dizzy but I have to follow the trail and try to make it better as I go.

This problem COULD of been anything I have already renewed???

I feel I'm missing something and it is something stupid, but I don't know what?

grounding it with a testlight on the control wire should make it spark. it just proves its a good coil

Hi,
I was going to ground the control wire with a jumper and T-pin, then....

take a test light and see if a spark will jump to an air gap at the test light.

When I turn it over.

If it sparks, does that mean it is NOT getting the signal from the ICM?

Right now, EEC Relay, Ignition Coil, AND Dizzy are all new MOTORCRAFT Parts!

I feel there is a short somewhere or a computer problem?

Any ideas on this? Any other ideas at all? Any experience with this???

Not getting a lot of feed back???

I'd still be suspecting the ICM at this point simply because I've seen so many fail. Try looking at some tests here though-
easyautodiagnostics.com/ford/4.9L-5.0L-5.8L/index-of-articles-1

GypsyR wrote: I'd still be suspecting the ICM at this point simply because I've seen so many fail. Try looking at some tests here though-
easyautodiagnostics.com/ford/4.9L-5.0L-5.8L/index-of-articles-1

Hi,
Thanks, those are the test I've been using!

Going to go back to square one and start over again.

Battery is charging back up and will try again with it fully charged.

As a side note, I ran this truck for 25 years and never had a coil problem, ICM problem, or a PIP sensor problem???

Thanks again!

Hey seagiant! Can you bring me up to speed on your testing so far? I just got done with another EEC-IV problem at work, so a lot of this stuff is fresh in my head. :lol:

Tyler wrote: Hey seagiant! Can you bring me up to speed on your testing so far? I just got done with another EEC-IV problem at work, so a lot of this stuff is fresh in my head. :lol:

Hi,
I think I may have stumbled on a clue.

I think maybe I have a short in the RF noise capacitor....

And THAT is keeping the coil from sparking???

I'm going to look under the coil and do some tracing and see if that is it?

Thanks for the help, if this is not it, I will get back!

I think I may have stumbled on a clue.

I think maybe I have a short in the RF noise capacitor....

And THAT is keeping the coil from sparking???

Possible? The only way that could be true is if it was a direct short, causing the fusible link to burn, and interrupting power to the coil and ICM.

Normally, the engine WILL run without the capacitor. So, if you have any doubts, you can disconnect it for now.

you said you dont have a pip signal. that comes from the distributor. sounds to me the "new" distributor might have a bad pip. do you have a scope??