Spark jumping

I have a bit of an erratic idle, the car's been missing while cruising and occasionally at very high rpm's(5800 or so). So I installed a new coil tonight and I was also checking the spark plugs in the dark to see if any of them were jumping. I noticed a few were on the pass side, one of them really bad apparently because the boot was white. I fixed that side by removing my heat shields from the plug wires....Now I just hope the boots don't melt or catch on fire!

I'm not sure what to do about the driver side...One wire is touching the dipstick tube and arcing to it occasionally, so I just need to find a way to keep the two separated. Then I noticed two of the plugs had a circular blue glow around them. I didn't have a light to see exactly where it was coming from, but I'm guessing it's around the threads. I tried to tighten one of them, but it was still pretty tight. My next thought was maybe I should remove the washer from the plug?

I just did a quick search on here and somebody mentioned the plug gap could be too large. I have it set to .60 I think, is that too much? I'm using Autolite AR3923(sidegapped) and Taylor 409 10.4mm wires. I also have a MSD dizzy, Crane Hi-6 ignition, and just installed MSD coil.

I bought these wires to try to fix my idle problem. They're only a year old with 1000-1500 miles on them.

I think I fixed most of the problem by removing these...They were touching the plug itself, and it looks like they might be a good conductor.


The only other arcing I noticed from the wires was to the dipstick tube. The glowing plugs are what I'm mainly concerned with. I've got an extra set of spark plugs, should I try replacing those two and see what happens?

I took the car out for a short trip last night and driveability was much much better, but it's still missing at high rpm's. That problem started when I installed new plugs gapped at .045(old one's were .055). I then put the old plugs back in gapped at .060 but it's still doing it. Should I change the gap back to stock? Or should I try some new plug wires?

BTW, I didn't get a chance to work on the spark problem over the weekend. I was too busy installing sfc's and lca's. I need a day or two break from the car, then I'll get back to working on it.

I don't have time so I'll just post a quick question for now...Should the coil light up at night? I see it lighting up blue on both sides of the coil.

More later...

That's good, I guess. Anyways, let me start this thread over since I think I confused you guys earlier....I'm good at that!

Everything I said I've done in this thread was done before I started the thread. I noticed sparks jumping pretty bad so I removed those plug wire heat shields. At the same time, I installed an MSD coil. That's when I started this thread.

I've had an occasional erratic idle almost since I got the new engine running. I didn't worry about it for a while because I thought a tune would fix it. I installed new wires(the ones I currently have), Crane Hi-6 ignition box, new O2's, and new plugs right before having it tuned. It ran great for a while except for the idle thing, so I tried to fix that. Gapped the plugs to .044 per Crane's instruction manual. It ran a little smoother, but that's when my 5800rpm miss started and I lost 15rwhp on the dyno(different dyno, different days...could have been partly weather related). So I put my old plugs back in gapped at .054ish(not .060) and the power was back but it's still missing.


Back to the present situation. After I installed the coil/removed heat shields, I took the car out and it ran perfect except for that miss at 5800. I had it out again a few days later with the same results. Then Saturday I went to a car show and it's back to running like crap. I read in another thread that the TFI is grounded through the frame, and I realized that I just zip tied mine on 2 years ago, so last night I got it mounted solidly on the frame. I still have the same problem! Could my TFI be bad? I tried switching back to the stock tune, and bypassing the Crane box but it still has a horrible miss while cruising plus the miss at 5800.

Could a jumping spark cause these problems? I noticed and OCCASIONAL spark to the dipstick tube and valve cover, but it's not constant like it was before. Also I noticed ALL the spark plugs are "glowing". I don't know if that's a problem, or if it's like the coil thing where it's not really a good thing but it's not a problem...

Also something I just remembered. At one point when I was changing plugs last summer, at least 2 of my plug wires had the metal pull partway out of the plug end. I figure that's part of the problem, but I hate to buy new wires since I paid almost $100 for these and they have less than 1000 miles on them.


Summary: Horrible miss while cruising, it's fine while accelerating until 5800rpm when it's pops/misses. Runs great one day and crap the next. Bad distributor? plug wires? plugs? TFI? Something else? Help!!!

:SNSign:

Sorry for the long post.

Nobody can help me? I've got a good TFI I can "borrow" from my parent's car, I plan on trying that this weekend. I also have an old set of wires I will try in place of the couple one's I'm not sure about if the TFI isn't the problem.

What about the dizzy/pip? First time I started my engine I had a bunch of air in the cooling system and the radiator hose popped off splashing water in the distributor. I don't know if that would have hurt anything or not. Everything but the TFI is new, or was recently new, but I've had a rough idle since I got the engine together and it's been getting worse.
Here's what the idle sounds like, http://www.mustangaddiction.com/movies/miss.wmv. Listen close at the 5-6 second mark. That's what's prompted me to change plugs/wires/coil/etc.

I don't know which way is cooler, but AFR lists the 3922's as the starting range for the 225 heads. I got the 3923's because, well, I forgot what one's I needed to get. I found the AR plugs at Advance auto like two years ago, but when I checked for replacements last year I couldn't find them on their website.

I don't think cracked porcelain is the problem....It IS always at the same rpm, but it's NOT always there...And it's done it with 2 sets of plugs.



Hmm....You know, it started running like crap again right after I washed the car....And my hood scoop is right above the distributor....That might explain the random missing, but it still misses at 5800 when it's completely dry.

Would there be any long term affects to water in the distributor? Because what I posted before happened 2 years ago when I first fired it up. Since that happened first thing, I can't tell if the dizzy is causing my idle problem or if it's something else.

Thanks for the advice, I've really got to get this fixed. We've been having all this perfect weather and I haven't been able to get the stang for more than a few minutes at a time!

HISSIN50 said:

Mike, given that it happens at cruise and at near redline, I doubt it's the TFI. If it was only at near redline, I'd consider a bad dizzy bushing but that shouldn't affect cruise condidtions.

Like Yellow, the plug wire stuff still has me kinda worried. I'd do shadetree sheathing and insulating to see if you can change the symptoms. If so, you can feel good about wasting money on new wires (I hate buying parts unless I know they're the issue). Really watch separation too - you mght have a cross fire going.

Good luck Mike.

Click to expand...

By separation you mean the plugs wires should not be touching each other? I was curious about that, because that's kinda what the idle thing sounds like to me....