3rd failed ignition module?

[FB71]

My tach is factory. It didn't have the wiring, so I wired it myself. I will try disconnecting the tach and see if that helps. Also, the wires are all in the correct positions. I do have access to a voltage and ohm meter. If you can tell me what wires / contacts I need to test, I can test them tomorrow. I really appreciate the help. I have been stumped with this and it's getting aggrivating.

I see the dizzy wires are connected to the correct vehicle wires (other wise it wouldn't have started at all), I'm just curious if you have the coil polarity correct. If you have all the positive wires on the coil negative, and all the negative wires on the coil positive, the resulting reverse polarity flyback will damage the module, because the diode inside that is supposed to protect it can't.

As for testing, check your voltage at the coil positive during cranking. It should be battery voltage (arond 10 volts during cranking). Can't think straight at the moment, I'll post more tests tommorow.

[FB71]

FWIW:
My ignition module and pick-up coil are like Jmye1524's.

hmm... well then, we should be able to wire in an HEI module. We just just need to determine pickup coil polarity...

[jmye1524]

I'll post more tests tommorow.

I would be interested in a way to test the pickup coil (should it have continuity)

And what to look for on the ignitor ( or does it have to be under load )


.

[Festy46]

Check the 2 wires going to the distributor for continuity. Remove them from the coil and the ignition module and use an ohm meter or test light to be sure that the 2 wires are not broken inside the insulation.

Like Jim said, make sure you have located the little "+" and "-" marks on the coil and have it hooked up correctly. If you did make a mistake and hook it up wrong, please let us know so we don't continue to try to troubleshoot it.

[JohnGunn]

Just finished reading the thread to this point and will give my reaction to what I have read.

I bought a new rebuilt dist. for a 88 Festy a few years back and the module was bad, it was a Beck Arney unit, took it back to the parts store and they honored the warranty, put next one on and it worked fine.

My guess is that you are currently trying to troubleshoot a defective "refurbished" distributor. I don't know much about carbureted Festivas so I'll not venture a comment other than to suggest finding another in a junk yard to use in proving that the "refurbished" one is defective so that you can get your money back.

The voltage input to the primary side of the coil is likely designed to handle some variation in the input voltage say between 10 and 16 volts, maybe more.
Corresponding to a dead cell in the battery or fully charged battery and maybe not so well regulated alternator output.
So where is the excessive voltage coming from unless his regulator on the alternator has failed such that the continuous DC voltage is in-excess of 16 volts?

Now wondering about your alternator, but if its regulator failed such that you were getting higher than designed voltage into the ignition system I would suspect it would have "boiled" the electrolyte out of your battery and you'd have had battery failures too, as well as premature lighting failure.
Guess we will see were this thread takes us!

When you finish troubleshooting your current "no start" problem you will still have to answer the question of what is killing your ignition modules. I think Pu241 is on the right track when he suggests that a defective voltage regulator in the alternator could be the cause. I would also think that would cause the battery to boil, but if this is an old battery with low acid levels in the cells it might be able to boil without overflowing onto the top of the battery. I would check the water/acid level. My impression from something said is that the battery is not new.

The ignition module is clearly a heat sensitive part. There was mention made of using thermal paste when installing it into the distributor. Also in reading this list over several months I believe I have detected an unusually high number of early, carbureted Festivas which had ignition problems, often non-starting, which were cured by replacing the distributor. Also of interest is the fact that for the fuel injected version of the engine the ignition module was moved out of the distributor away from the heat of the engine and attached to the driver's side strut tower. It also has a substantial heat sink, though no thermal paste. This suggests to me that the company recognized this as a design problem.

As I recall, the various modules did not fail immediately. It took some time for that to happen. That also suggests to me that the problem might not be the result of a single spike of voltage from the alternator or even a consistently, grossly excessive voltage level, but possibly a slightly above spec level that damaged the module slowly over time through constant heat stress. You said you had not seen any indication of problems with the alternator, but this hypothesis is based on a failure that might only show itself on the weakest element of the ignition system, the ignition module.

In your position, once the engine is running, I would what to test the charging voltage that the alternator produces at all rpms up to 4,000. The charging voltage given by Haynes is 14.1 to 14.7 volts. Then I would want to remove the belt from the alternator pulley and turn it by hand to see if I could still feel any braking action of grease in the bearings. If it spins freely, it is not new and I would replace it. Then cross my fingers and go about my business.

John Gunn
Coronado, CA

[Banana Bonanza]

hmm... well then, we should be able to wire in an HEI module. We just just need to determine pickup coil polarity...

I dont think pickup coils have polarity. I was worried about such long time ago when I first did an HEI module in a Volvo. It didnt matter, but if for whatever reason it doesnt work one way switch leads around, you cant really damage pickup coil unless you try to apply current to it. Main thing is to check if the pickup coil is good. The manuals usually give a resistance value range to look for but usually if there is continuity they work.

My Festiva module/pickup is two piece also, no idea that they made one piece combo units, did think it odd they had them fit so tight. But if they were one piece, just find a pickup coil off some other application and adapt it. After all its just a little continuous coil of very fine wire.

[Banana Bonanza]

Also of interest is the fact that for the fuel injected version of the engine the ignition module was moved out of the distributor away from the heat of the engine and attached to the driver's side strut tower. It also has a substantial heat sink, though no thermal paste. This suggests to me that the company recognized this as a design problem.

I know nothing of fuelie Festivas and have only had the one carb Festiva. But BINGO I think we have an answer with the design change. Really sounds like they knew there were heat problems. I do know enough of ignition modules to know its nearly always heat that destroys them. It is odd if what you say is true that fuelie modules are mounted external to heat sink on strut tower, that they didnt use some sort of thermal paste. You mount an HEI module without thermal paste and it dies very quickly. The Ford and Chrysler ignition modules from 70s were larger bulky things with their own heat sink as part of the unit. The Ford unit actually pretty good, just bulky. The Chrysler unit not so good IMHO. I had a '76 Dodge pickup at one time and quickly learned to ALWAYS carry a spare module and a spare dual ballast resistor. It would go through these at most inconvenient moment. Far as I cold tell, the heat sink just wasnt big enough in them. Back then without a spare, it meant a long walk (no cell phones back then) This was way back before I learned that I could use a GM module on nearly any pre-computerized electronic ignition. If I had known, I would have put a GM module on that truck.

[doylerl]

I removed the tach wire, and still nothing. I am waiting for the GF to get home so I can see how much juice the coil is getting while cranking.

[doylerl]

I did a continuity(sp?) test on the wire harness from the coil to the module, and everything appears to be fine.

On my harness, there is barely enough wire to plug the wires in, and deffinately not enough to switch any of them around. Two of the wires have rubber on the connectors:
rubber connector on top, then metal connector with no rubber, then another connector with the rubber again on the bottom. I tried again today to have them tested, and autozone and advance neither one have the right wiring pigtail for their machine. I am awaiting Jim's (FB71) instructions on how to test further.

[FB71]

I dont think pickup coils have polarity. I was worried about such long time ago when I first did an HEI module in a Volvo.

ah, but there is a polarity! Every coil has a direction in which it is wound, either clockwise or counterclockwise. As the tone vane passes the coil, it induces electron flow within the coil of wire. The direction of winding determines if the AC pulse generated has a falling slope first, followed by a rising slope (falling trigger), or a rising slope first, followed by a falling slope (rising trigger). Most HEI module trigger on a rising slope, with the exception of the few goofy ones with the reversed coil output (don't remember the vehicles). If the pickup coil is wired in backwards, the best case scenario is that your spark advance will be off by two or three degrees. The worst case is that the reverse flow in the pickup creates so much distortion of the signal, due to inductive reactance, that you can't get a consistent advance or saturation time (dwell). Wiring the pickup backwards won't actually hurt the module, though. HEIs have the best coil current control I've measured, better than Ford's Duraspark (which was nearly indestructable!) and Chrysler's Transistor Ignition.

[jmye1524]

After we figure out the problem at hand, it would be neat to have a "how to" on wiring in a remote mounted HEI. ( with detailed pics)


I think you have a great idea Banana Bonanza, thanks for bringing it to the table.

[FB71]

I did a continuity(sp?) test on the wire harness from the coil to the module, and everything appears to be fine.

On my harness, there is barely enough wire to plug the wires in, and deffinately not enough to switch any of them around. Two of the wires have rubber on the connectors:
rubber connector on top, then metal connector with no rubber, then another connector with the rubber again on the bottom. I tried again today to have them tested, and autozone and advance neither one have the right wiring pigtail for their machine. I am awaiting Jim's (FB71) instructions on how to test further.

First, continuity checks are nearly useless. We need to measure voltage drop. This gives us the working resistance (resistance under load) of the conductors. That's why I want you to measure the voltage at the coil while cranking. Compare that voltage to the voltage of the battery while cranking. If there is a significant difference (more than 0.2v), we have a resistance issue.

The wire you checked either carries voltage to the module for it to operate (milliamp load), or ground side current to the coil's primary winding. Resistance checks for those are also limited in what they tell us. Voltage drop is the only way to go.

We also need to check voltage drop from the distributor to the battery negative terminal. Again, measure during cranking. If the voltage is greater than 0.2v, we have a high resistance issue in the ground path.

Have you checked the coil's internal resistance? Disconnect all the wires from the coil, but don't remove it from the bracket. Check across the two terminals. The resistance should be 1.0 to 1.3 ohms. If that reads ok, check from the primary positive terminal to the secondary tower. That should read 7.1k (7100 ohms) to 9.7k (9700 ohms). If that reads ok, check from the positive terminal to the case. It should read infinite resistance (OL on many meters). If any of these checks fail, replace the coil.

[FB71]

After we figure out the problem at hand, it would be neat to have a "how to" on wiring in a remote mounted HEI. ( with detailed pics)


I think you have a great idea Banana Bonanza, thanks for bringing it to the table.

absolutely, thanks! I just need to dig up a carbed dizzy and verify polarity! That should be an easy how-to!

PS - I run an HEI module in a parallel twin motorcycle engine, witha pickup coil from some Toyota dizzy grafted to the bike's original breaker plate. HEI modules are fun!

[FB71]

I did a continuity(sp?) test on the wire harness from the coil to the module, and everything appears to be fine.

On my harness, there is barely enough wire to plug the wires in, and deffinately not enough to switch any of them around. Two of the wires have rubber on the connectors:
rubber connector on top, then metal connector with no rubber, then another connector with the rubber again on the bottom. I tried again today to have them tested, and autozone and advance neither one have the right wiring pigtail for their machine. I am awaiting Jim's (FB71) instructions on how to test further.

PS - new parts don't always mean good parts!

[FB71]

I would be interested in a way to test the pickup coil (should it have continuity).

great question, yes. Not sure how much resistance but probably around 2-3ohms.

And what to look for on the ignitor ( or does it have to be under load ).

Unfortunately, yes, it must be stress-tested (loaded). We then look for appropriate voltage drop.