Flabbergasted ll

[drddan]

Went out to see if i'm getting fire today and here's what I found:
Plenty of spark out of the coil as it shocked the crap out of me holding the coil wire close to the distributor. Lots of spark there!!!
(51,000 volt hi perf Mallory coil)
Pull the plug wires, nothing! No spark coming from wires. NEW Taylor wires, maybe 6 months old. New cap and rotor at the same time. All looks ok in cap/rotor. Here is the orig thread:
http://www.fordfestiva.com/forums/sh...ad.php?t=30389

Is there something that would cause this? Ignition module should be good as its getting spark from coil to distributor. I am going to buy new cap and rotor, just because.

[mechanicaldj]

rotor in distributor cap is on backwards

[eurotiva]

rotor in distributor cap is on backwards

x2

[FB71]

just because it shocks you, doesn't mean the coil is good. Only takes a few hundred volts at a few milliamps to really feel like you've been nailed hard. If the rotor is on right, I suspect the coil.

[drddan]

rotor in distributor cap is on backwards

^Yeah, thats why its been running great for the past 7 months. Guess it just flipped itself around! WTF! How about a good answer. :p
This is an extension of a previous thread. Car just went bonkers about 2 weeks ago. Next up: Checking the timing belt?
Fb71: The spark from coil is strong, arcing well over an inch to the disty cap, and quite a bit of visible spark, but nothing coming out the good, new wires, to the plugs.

[qlopp]

You didn't give kv measurements or specific test procedures/results, you only mentioned a zap feeling, so accept the generic answers that will come from your question.

If your distributor has been turned (reindexed), you may have induced too much rotor gap, IOW the space between the rotor tip and the cylinder contacts is too great to jump and make it to the plug wires.

You also only "checked spark" apparently by holding the coil wire. The wire may be open and you may have been shocked by an arc from the coil tower itself or from a breach in insulation. Get a gap tester or fashion one up at the very least, and check at the end of the coil wire, then check at each plug wire until you find where the problem lies. If spark jumps a controlled gap at the end of the coil wire but not at any plug wires, suspect rotor gap, be it from turning the dist housing, having the rotor on backwards, or even a broken timing belt or other cause of the distributor not turning.

Finally, the rotor could be conducting spark to ground (distributor shaft) through carbon buildup or a crack. Check for that if all else is OK.

[drddan]

You didn't give kv measurements or specific test procedures/results, you only mentioned a zap feeling, so accept the generic answers that will come from your question.

If your distributor has been turned (reindexed), you may have induced too much rotor gap, IOW the space between the rotor tip and the cylinder contacts is too great to jump and make it to the plug wires.

You also only "checked spark" apparently by holding the coil wire. The wire may be open and you may have been shocked by an arc from the coil tower itself or from a breach in insulation. Get a gap tester or fashion one up at the very least, and check at the end of the coil wire, then check at each plug wire until you find where the problem lies. If spark jumps a controlled gap at the end of the coil wire but not at any plug wires, suspect rotor gap, be it from turning the dist housing, having the rotor on backwards, or even a broken timing belt or other cause of the distributor not turning.

Finally, the rotor could be conducting spark to ground (distributor shaft) through carbon buildup or a crack. Check for that if all else is OK.

All good answers. Again, the coil, wires(Taylor brand), rotor, disty, disty cap, fusible links(now fuses) all have been replaced 6-7 months ago. This car has been running great. Better than when I bought it a year ago. Strong running (I beat other Festy's!) 2 weeks ago it just went bonkers.
(See Flabbergasted thread for description)
Beginning to think the timing belt jumped/broke. Didnt think to check the rotor for movement when cranking, when I had the cap off! Duh! I will do this tonight. I did have the timing advanced, so it had extra stress on it.

[qlopp]

Beginning to think the timing belt jumped/broke. Didnt think to check the rotor for movement when cranking, when I had the cap off! Duh! I will do this tonight. I did have the timing advanced, so it had extra stress on it.

(More) advance timing causes the spark to occur under less compression, so it is actually going to stress the secondary system LESS. It IS more stressful to the internal engine if the flame kernal partially ignites the fuel mix before the proper time e.g. crank angle. The sound of detonation or "pinging" is proof that excessive timing advance is bad for the engine. Spark kv demand actually goes down, however.

You should have heard un unusual cranking pace from the engine while trying to start it IF the timing belt did break. Normally during cranking there are evenly spaced fluctuations as every cylinder hits TDC compression. When the valves aren't turning, then some cylinders will have open valves while at least one will have both valves closed, causing an uneven lope to the crank speed and sound. If the valvetrain is simply out of time (slipped belt) then the engine will not be able to produce as much compression and it will crank faster than normal. These are two simple things to listen for that will speed up valvetrain diagnosis considerably.

[FB71]

If you have spark, the dizzy is turning. The dizzy sends the PCM the signal to fire the coil. However, you may be on the correct path with suspecting the timing belt having possibly skipped.

[qlopp]

I did have the timing advanced, so it had extra stress on it.

To address another possible meaning you may have been conveying with this statement...


I did reference that excessive rotor gap will cause no spark. Advancing the distributor (on any vehicle design I'm aware of) just a bit for an improvement in performance will not come near the point where rotor gap is an issue. Rotor gap is an issue generally on late 90's trucks that use a cam sensor in the dist housing and don't rely on distributor positioning to create spark at the correct time. In these systems, the distributor could be turned 20 degrees from ideal and the engine computer will still request spark at the right time via the crank sensor. The side effect will be while cruising with a lot of advance (40 degrees or so) the rotor will be so far from the cylinder contact(s) that spark can't even jump it anymore, and/or it jumps it but there isn't sufficient energy left to fire the cylinder at the plug gap.

I simply mentioned rotor gap because, without any testing details, it was possible that you may have turned the dist at one point so far that the rotor gap couldn't be jumped. In most cases, and given that you are testing spark at atmospheric pressure which is the least difficult condition for it to jump, if the rotor gap was anywhere near correct then the spark should have made it through.

A broken timing belt could strand the rotor at 45 degrees between contacts, or it could have lined up with a cylinder whose plug wire you did not check, because you were assuming the dist was turning and would eventually reach the wire you tested.

[eurotiva]

Sorry my answers suck. First I would remove that crappy coil and stick with what works STOCK!!!!

Others have had issues when using other coils. Why even waste the time and money, some of the baddest/fastest cars here are running stock 20 yr old coils.

Just my $.02

[qlopp]

If you have spark, the dizzy is turning. The dizzy sends the PCM the signal to fire the coil. However, you may be on the correct path with suspecting the timing belt having possibly skipped.

Good points. The other unlikely possiblity with a stripped belt is that the crank gear is catching a piece of belt tooth and making the dist dither back and forth, which is triggering a spark repeatedly, though the cam and dist aren't really turning. I have seen this before with just the right conditions. Usually it happens on a cold start when the crank gear shears off the "bottom" teeth of the timing belt, then it keeps trying to grab the belt by the remaining side teeth but they keep letting go, then the valvetrain spring resistance keeps returning the belt back to square one and the cycle repeats.

[TominMO]

OMG, Greg's answers suck!?!?!?! And I let him work on my car.........:banghead:

[Pu241]

OMG, Greg's answers suck!?!?!?! And I let him work on my car.........:banghead:

Work on your car my butt!
He replaced your cars entire drive train and added a rear turbo too!
He did a little more than work on it!
Hell, I've worked on your car.
Greg performed magic!:notworthy:

[drddan]

Sorry my answers suck. First I would remove that crappy coil and stick with what works STOCK!!!!

Others have had issues when using other coils. Why even waste the time and money, some of the baddest/fastest cars here are running stock 20 yr old coils.

Just my $.02

Did that. Old coil made no difference. Thanks though. Curious, how is a Made In USA, Mallory coil, crappy? I dont get that part.

Greg, I'm in my 50's, been working on cars my whole life. I am NOT an expert, but I do know how to put on a rotor and cap. I even checked the rotor just to be sure. Cant put the rotor on backwards on mine without using a big hammer! I do have questions when it comes to the electronic ignition systems, as I am not fully aware of how, all the componets work together.
I can replace them, but have issues with trouble shooting the ignition componets to find out which is causing the problems.