82 F150 302.....

New EVERYTHING ignition related except the distributor and Duraspark module. It has an aftermarket MSD rotor and cap, a blaster II coil for durasparks, 9MM Ford racing plug wires.

non igniton related upgrades include Edelbrock perfomer intake and carb.

1. No vacuum leaks, verified with gauge numerous times.
2. Timing is at 10 BTDC
3. Carb is pretty much dialed in to where I want it, plugs look good, crisp throttle response, lots of power for a 302.
4. Plugs are also new.
5. While I stated that the durasaprk box isnt new, I grabbed the one off my 73 and plugged it in, no change

symptoms:

1. irregular idle issues, does it sometimes, sometimes it doesnt. It idles a little rough when it does it, when it doesnt, it runs so smooth I cant even tell the trucks running except for being able to hear it.
2. When I was doing the timing the light would lose a spark pulse occasionally, no pattern to it at all, it would flash consistently for 30 seconds, then lose one pulse, then flash with each fire again correctly for 10 seconds, then miss every other spark fire for 3 or 4 cycles in a row, then do fine again Etc. Etc.
3. This only happens at idle, at any other application of throttle it runs like a top
4. I do not like the spark you get when the wire is pulled off the coil and the engine is cranked over....it was yellow and weak before the new coil,wires,plugs,rotor,cap, and new/used duraspark box that I listed above......it is yellow and barely stronger after these upgrades, but it is a little better.
   

It has good grounds, and a brand new (last year) Optima battery


So, do I have 2 dying duraspark modules, or do I have a bad pickup in the distributor or something?

Or do I (not likely) have a bad Craftsman professional timing light? In which case I still have the weird idle issues

Ive fiddled with this for 2 months now, trying everything I know and tapping the minds of quite a few of my knowledgeable friends, mostly NW chapter members. So that said Id like to open it up for everyones ideas.

I dont care how stupid anything sounds at this point, fire away guys

 

Kevin, first things first let's rule out the timing light. I have one at my house (yes, I DO own a timing light ) that you can borrow just to make sure the light isn't the issue. Judging by the fact that you're experiencing some problems with your idle, and not just missing flashes with the light I would say the timing light probably isn't the culprit here but better safe than sorry. This is kind of a silly question but have you tried the light on other plug wires to see if all cylinders are experiencing the same symptoms?

The Duraspark boxes are pretty cheap brand new, so it wouldn't hurt to get a new one and try it. If it doesn't solve it then you'll have a spare incase one of the boxes in either truck craps out on you later.

You mention that the spark looks weak in the 82. Have you grounded a spark plug on the 73 to compare them? Another stupid question but have you put a multi-meter on the electrical system at idle to see if there are any voltage irregularities at idle that might be causing problems?

My last thought, in light of the trouble I had with my truck a few weeks back. The 9mm plug wires you just put on, did they come assembled or did you cut them to length and crimp the ends on? If you did I'm just wondering if maybe the core isn't making proper contact with the terminal and you're losing spark there. You might also check the spark directly from the coil and see if it's any stronger than what you're getting at the plug end of the wire.

Alright, I've drained my brain on this for now, that's all I can think of. Let me know if you want to borrow my timing light. I'm away all day but if you're by the house you can grab it or I might be able to drop it by tomorrow.

 

Maybe Ill swing up your way and see, it would only take about 2 seconds to see if thats the problem, but that light has never done that before, Im 99.9% sure it isnt the timing light. It doesnt do it on any of our other rigs

Actually, yes I did. But to give a silly question to a silly answer it was 4:30 in the morning and I got a wild hair up my butt and now I cant remember what the results of that test were, but I think it was doing it on the other cylinders too

I agree, and planned on it anyway, I just wanted to hear some other peoples points of view before I started throwing $ at it

Spark on the 73 is a nice hot whitish blue, Angelas used to be like that too, no on the multi-meter, thats one I havent thought of. Ill try that today maybe

they were cut and crimp because Im a moron and ordered the wrong part number, but the spark is weak at the coil, not the plug end, which I suppose rules out the dizzy. This whole problem is starting to make my brain hurt I suppose. I havent actually checked spark at the plug end, one more thing to add to my list for today.

Its not the timing light, unless those big beefy wires are too much for the light to pick up through (not)

So Ill stick my multi meter on some stuff and watch for fluctuations, check the light again on the other wires, and Ill check an actual Plug today and compare spark at coil versus spark at plug. Like I said however, spark at the coil is weak, Its BETTER though now than it was before I put all this stuff on...... In other words, It has a weak spark with the Blaster coil, or with a stock duraspark coil, makes little difference. remember that this is happening before AND after the new coil, wires, plugs, rotor, cap, and using two different boxes.

I went to albertsons this am for some stuff for breakfast, and as I parked the truck, it idled rough, and was so rythmic that it seemed like it was dropping a cylinder, it was worse than it ever has been. After coming out of the store it Idled smoother than a babies butt, the irregularity of the problem makes me keep thinking Duraspark module...

She took her truck to school, I made sure she had her cell phone with her, and I expect a full report on symptoms when she gets home. It never seems to happen to her though, just me, shes opposite of most women

I wonder if an MSD 6AL and a Pro-Billet dizzy would fix anything

Thanks for your thoughts and time...... you at least thought of a few things I havent....

anyone else?

 

If the timing light works on the other rigs fine then that rules the light out. You're welcome to borrow mine if you want but I don't think that's the problem.

Did you use an actual spark plug wire crimper when you put those wires together? If so was it set up for 9mm wires so you can be certain you didn't nick the core when you stripped the insulation off?

I agree, the intermittent pattern here really is looking like the Duraspark, I just don't get why it does it with both boxes when the 73 doesn't have these problems.

 

Good point on the 73. Good point on the wire crimper too, and I didnt use an actual spark plug wire tool, I dont have one, but it had this problem before it got new spark plug wires.

Angelas home from school.... she said it ran flawlessly for her (figures)

Im gonna go out and dink with it

 

I've got a plug wire crimper if you ever need. It's really important that they be done right or you can start losing power and having wire issues. Mine are set up for 8mm, 8.5mm, and 10.5mm. You could crimp a 9mm in it fine, you just would have to be extra careful about using the guide to strip the insulation off. Anyway, I don't think that's the problem but something you might try just to rule out a bad wire connection is take the coil wire from the 73, put it on the 82 and throw a spark plug in the end just to compare spark and make sure the coil wire doesn't have a poor connection. If that don't solve it the box it about all that's left here.

 

New box, so far so good

 

If it still gives you trouble on certain morning start-ups, and then runs fine after it's parked for awhile and then re-started, I bet you are getting a little bit of carb icing if it's cold where you live right now.

If you still have the yellow spark, take a voltmeter and read the voltage from the + terminal of the coil, with the -lead of the meter on the engine block. I would be curious what you get.

 

It always starts fine in the morning, and doesnt do it until the truck is warm, it never does it cold.....

We'll see if the new Duraspark module does the trick....

I fiddled with some other things, including carb jets and rods today too, and during test drives everything was A-OK so far

Fingers crossed that its just the duraspark module

If its still doing it Franklin Ill whip the voltmeter out next and post up

 

If the new module doesn't fix it, its probably power delivery and not ignition.
for the first thing, try running a ground wire directly from the factory ground terminal on the alternator to the neg battery cable. see if that has any effect on the misfire.

I'd like to know the voltage to the ignition module when the misfire starts, and if its different when its running good.

 

Great minds think alike, I bought one today when I bought the Module........


But I decided to call it a day and its still sitting in a box in the garage

 

Kev, I'll agree with Bob and go with the input voltage... a bad/partially grounded connection between the alternator and the module. You may need to unplug everything and check for a high resistance in a path from the alternator to the module or a path to ground that shouldn't exist.

A multimeter may not give you a high enough voltage to detect a leakage to ground... that's where a megohm meter comes in... who has one? got me, see if Mark can get one (if they have one at work). If you have an open that changes with temp, that could be a problem.

I had a problem on the '82 that was related to the electric assisted choke, when the truck was warm and the choke was open, it ran fine. I disconnect the choke and it improved slightly... I removed the wire completely... guess what... I found the leakage to ground. Replaced the wire and the truck ran good.

These durasparks seem to be sensative if they don't get the right voltage. Also see if you can jumper the input to the voltmeter and see if the input jives and clean your connectors out and do the silicone grease on everything.

-Kerry

 

Ill keep everyone posted. As much time as Ive put into Carb tuning, vacuum leak checking, and Ignition system testing, It wouldnt surprise me if thats whats wrong.

We'll see

 

One easy check is the play on the distributor shaft. Warm things up, pop the cap and wiggle the shaft back and forth. Sometimes the bushings get worn and weird things happen. When they get really bad I've seen problems at idle and high rpm. Not that hard to pop the dizzy and rotate it by hand either. Might be starting to egg out.

 

What am I thinking...

I was going to suggest trading out plug wires, but it's been addressed.

Have you considered swapping the strib out of the 73, or maybe the pickup mudule?

Things I can think of on distributors are shaft wobble from bushings, a weak pickup module, or - the leads from the pickup module to the wiring harness being damaged. (On some early breakerless ignitions, the leads to the pickup module were not long enough, and the advance mechanism yanked them until the conductors inside were damaged)

I did see an advance plate in a 351 once that had shattered somehow, but that was a breaker point system.

Only other thought was a seal on the shaft allowing oil up into the works.