Featured Technical New guy with odd electrical problem

IIRC, you said something about the alternator wire was temporarily shorted to ground. Knowing that, I would disconnect the alternator from the battery and see if the no start and flashing gets resolved. Just a possibility.

 

I have tried cranking with the alternator disconnected with no change. Had the alternator tested and passed, charged at 13.9-14.5v when it was last running. Thank you for the suggestion.

 

It's very tough to diagnose electrical issues long distance, but I'll throw out some ideas.

The test light flashing while connected to the coil when cranking is normal. The interior lights, you say they 'flash' when cranking. Do they go out, or simply dim? And how much do they dim if that's what they do? If anything, that may be an inadequacy in the harness design but isn't something I'd worry excessively about if everything works otherwise, i.e. when running.

'Voltage drop'. Are you checking this with a voltmeter, or just a test light? The test light won't give accurate info, you need to physically measure it with a voltmeter. Put one lead at the battery, the other one at the positive end point of the circuit. The meter will read the actual drop. 5% is acceptable, once you get past about 7% or more you can have issues. This is while running, not while cranking. The big issue with one-wire alternators is they lack the upstream voltage sensing that actual automotive alternators have, so don't compensate for losses at the fuse panel. This is why Detroit didn't use them on cars.

This brings me to the ignition system. This is where the main problem is. So...

I also suspect it's a coil issue. First, are you sure the module/coil combo you have is compatible? Pertronix sells several modules, some require specific coils to work right. Some also require a ballast resistor depending on the coil used, something you haven't mentioned. A lack of one if needed could explain the rapid heating of the coil when idling, as well as the module failures. The module should have a spec as to minimum primary coil resistance without a ballast resistor, I would check your coil to make sure you're not below that minimum. If it is, a ballast resistor will be needed along with additional wiring. I'd also check the wire size feeding the ignition (including the wiring to/from the module), anything smaller than #14 may be causing too much voltage drop. Because the coil is an inductive load, low voltage will cause current to go up, further stressing the module.

Coil heating is inversely proportional to engine speed and increases the load on the module. More RPM, less heat build-up from high current unless you have an ignition that features 'dwell control' or has current-limiting circuitry, features generally only found on the higher-end units.

One last thing... You mention you're running a blower. This puts additional load on the ignition system, you may not have 'enough' ignition for that application.

Hope this helps...

 

You seem to be fixing things that won't cause a no start condition.

The first thing I would do is pull the coil wire out of the distributor cap, hold it about 1/4 inch from a good ground, and crank the engine over. If you do not have a spark, your problem is ignition based.

If you do have a spark, replace the coil wire in the cap, pull a plug wire and put a spark plug in it. Lay or attach the body of the plug to a good ground and crank the engine. No spark at the plug means the problem is in the rotor, cap, or plug wires. If you do get a good spark at the plugs, your problem is not ignition based. I'd start looking at the fuel system at this point.

 

The interior lights dim. Less now than before with the new alt and starter. Not 100%certain, but looking at videos when I first got the car running, it does not look like the lights flashed before all this started.
Voltage drop tests done with a volt meter while cranking. Wasn't able to check for the short time the car ran last time.

Coil and module are matched. All 3 modules were the same part number, even waited on hold for an hour to talk to pertronix tech who gave me the same part#. Coil is 1.5ohm for 12v, V8 applications, no resistor, epoxy filled to lay down. Last I checked, coil had full voltage to it, but I will verify again.
The blower is a little weiend 144. It made 5-6psi boost on a 355. Same pullies on a 406ci. with maybe 8.5-1cr. ,I'd be surprised if it made 5psi now. Plus, it only makes boost under wot, otherwise it runs just like stock. Only been into boost a couple times before any of this started.

I was going to relocate the coil under the dash and mount an oil filled unit verticle as I have heard they run cooler. Hopefully be able to try that this week. Still going to do more testing on all this.

 

Didn't read the whole thread, But....
Last year at Bonneville, I fixed an issue like this, Because someone took the fuel injection off, An regulated the hi psi pump down to 5psi, Over heated the pump, Simply put a 4-5 psi pump on, Still haven't touched it a year later...

 

Are you sure the grounds are good ?

 

@Basketcases
The 144 should Not affect what you're experiencing/ issues

 

You have to expect lights to dim when engine is cranking, as starter is using so much battery that lights are getting a good deal less than full voltage.

 

Mount your oil filled coil so the connectors are at the top.

 

Are the Diode good in the alternator,they will play hell on electrical ignition

 

Jaracer and Hollywood-East, fuel system is good to go. No issues there. I have narrowed the issue down to ignition/electrical system.

Swade41, grounds have been taken apart, cleaned and reinstalled several times, as well as added a couple more since this has began. I will be going back over all of them again though as I am a big fan of good and extra grounds.

19Eddy30, I didn't think it was part of the issue. I was responding to someone saying it may cause issues. It's basically a stock sbc 400. Thinking about it, at this point the car actually hasn't even seen full throttle yet.

Pprather, Early videos of the car cranking before it was even on the road do not show the lights dimming. If they do in the video, it's so little it's not noticeable. The l.e.d. lights when this started, would almost go off, then back to full bright with every Rev of the starter. It still dims now, but less with the new battery or starter. I had to relocate and make a new bracket under the dash to mount the coil vertically. That is done and probably picking up a new coil this evening.

Sdluck, the alternator was tested previously and checked fine. Just to be sure, it is out of the car getting tested at the parts store as I am writing this. Guess we will see if that is another part that was fine, and now tests bad after all the other parts have been replaced.

Thank you all for the ideas. I'll let you all know what happens next.

Thanks
Mike

 

Recently had a similar no start . It was the wire from coil to cap . After many years of being a mechanic, this resistor wire went completely open . Looked fine on the exterior and was less than a year old . I switched out a plug wire and it started. Running on 7 cylinders of course but a great relief.

 

carbon wire???

 

Yes . Resistor. Required on most pertronics stuff .

 

Go back to a stock distributor and coil, it'll fix the problem and sell the Pertronics stuff to pay for your new parts. I had a Pertronics on a SBC in a 49 Merc and it failed as soon as the engine compartment was up to operating temp. GO STOCK and be driving. JW

Another thing to check is air leaving the engine compartment, there should be a clear and large path fot the hot air to go out.

 

Well alternator tested fine again. Picked up a new coil and relocated it, so it should get a little more airflow. If something happens to the pertronix again I'll go back to points until I can modify the firewall to accept an hei dist. I have a friend that has had the same pertronix unit installed in 2 cars for 15+yrs and hasn't had any trouble with either one. I will find out either late tomorrow or Saturday.

 

Well new Edelbrock coil got the car to start and run. Voltage at alt was 14.5v, voltage at coil was 13.79v running. Ran the car multiple times testing to full warm when the fan kicked on and was fine. Drove it around the block a couple times and was overheating, fan wasn't turning on, checked and thought it was a bad connector in the inline fuse holder but upon closer inspection, the fuse was melted but not popped and the plastic holder melted around the pin and dropping connection. Replaced it and all was good. Never seen the plastic on a fuse melt but not pop. All was fine, running at normal temp, no issues for 13.9miles. Now here I sit on the side of the road again, no start, no spark. New coil at 200°. I am at a complete loss again. I was coming to a red-light slowing down running fine. When the light changed, gave it some gas, the car stumbled for a second and dies like someone just flipped a switch. Pulled over, car wouldn't restart. Checked and no spark again. Fuel pump still running, 7psi and fuel in the bowls. Got home on a wrecker, didn't want to push it uphill into the garage so tried to start it and if fired right up, literally just bumped the key. Pulled it in and shut it off. Only thing I can think is the coil is getting too hot and dropping spark. Why, I don't know. Went over all the grounds before this last drive. Cleaned them even if there was no corrosion, moved one just for good measure. Might add one or two this week in other locations just to be even more sure that isn't an issue again. I have an email in to pertronix support to see what they think. Went over the install instructions again and it's installed to their specs. Guess we will see.

 

It happens when there is a poor connection between fuse and holder, the voltage drop in combination with the current passing through causes heat.

 

This sounds like a bad module if you had a GM style HEI in the car. What does the Petronix have in common with those? Maybe a bad ignitor?

For shits and giggles, I would try a stock HEI in it.

 

I feel your frustration !
Years ago I spent a lot of time looking for an electrical problem only to find it was a intermittently blocked fuel line.
I have been chasing fuel issues on my daily diesel for almost 12 months, only to find an electrical issue today, (a failing wire to a fuel sensor).

After reading the entire thread, I also wondered if you may have a fuel delivery issue, something like a blocked fuel line.

I hope that you get it resolved soon.
.

 

"Well new Edelbrock coil got the car to start and run. Voltage at alt was 14.5v, voltage at coil was 13.79v running."
You may need a blast resister feeding the coil, unless the coil has one built in. 13.79 seems like too much voltage at the coil, it can make it run hot and fail.

 

Hey Mike after we texted last night I thought to my self, self go check the HAMB and see if there’s a thread that might help Mike and Rob out, boom there you are with a thread. Wish I had an answer, between Crazy Steve and the rest of the members there is a lot of knowledge here.

 

To make sure I understand what has recently transpired, you replaced alternator, starter, and coil and it was running again. Voltage tested on the high side of normal. Then driving the car electric fan wires get hot and melt the plastic on the connector, coil gets hot, and car stops running. Did read if the lights stopped flickering while cranking, but it seems there is something goin on with your charging system. Were you monitoring the voltage while you were driving? If somewhere in the system there is a something shorting out (creating a dead short), it would cause the alternator to over charge and could be causing the other issues. Are there any other signs of potential over charging such as the batter top venting, other wires becoming discolored or hot to the touch? Did you hit any big bumps while driving that could triggered the short? Any other things that require a lot of voltage happen about the time you reached the stop light and the car started running poorly? When did the fan kick in? How is the fan wired? Could it be causing the excessive amp draw and sending the alternator into over-charge mode? Sorry if you have already covered all of this.

 

Petronix 11 I had caused the coil to over heat. GMC Buba told me to get a Bosch blue coil an aballest resistor. Car ran fine for several years. Started very quickly. I left the key on and smoked my Petronix. Had a stock distributor on hand. Car started an ran good. Went back to Petronix 111 and their recommended coil. Car starts great and runs super. Fingers crossed.

 

Bobss396, unfortunately an hei unit will not fit as the firewall is too close. I need about ¼" more clearance. Tried banging on it after this all started but its too stout. If this doesn't get sorted soon, a little cutting and massaging could be in the plans this winter.

Clem, the only fuel issues originally was a bad vented gas cap and fuel pressure wouldn't drop low enough. Fuel pressure is currently 6.5-7psi but I'd like to drop it down another pound but that's a minor issue. New cap and this winter I will drop the tank to adjust the fuel level gauge and will add/modify the vent on top of the tank. Everytime the car has died, I can still see fuel in the sight glasses on the bowls.

BJR, I have an email in to pertronix tech support to find what they recommend to the coil. The instructions say to remove any ballast resistor from the original points system as it's not needed. This is where I am at as well. While 13.8 seems high to me as well, I have not been able to get an answer as to the recommended max voltage for their coil. Hopefully I hear back from them soon.

Snoc653, the lights do still flicker/dim when cranking. Only voltage monitoring while driving was on the dash gauge. Not exactly accurate, but it stayed steady and right at the 14.5 mark while driving. Never saw it drop or spike. I have not seen or been able to find any wires that were showing signs of excessive heat or melting. I have been looking for anything like this since this started. The fan was working fine for the 3-4 days prior to the last drive, as I would start the car at least once while working on it and run it for 10-15min till it reached temp to kick the fan on, then let it run till the fan pulled the temp back down enough to turn off. That's why it was a shock when I drove the car to top off the gas and back to the garage to make a quick linkage adjustment and it started dumping water out the overflow. That was a new issue and I have to assume it happened on that drive. For the 14miles after I replaced the fuse holder, the fan kept the engine temps in check without an issue. Fan was wired with a fan temp relay kit. I haven't been able to find any shorted wires, I have no popped fuses and everything else in the car is working properly, besides the coil/ignition system. Last couple times it was running with the dash apart, I did try and move/lightly wiggle some wires to see if I could make the car die from a loose or bad connection and I could never cause a problem that way.

325w, I just waiting to hear back from pertronix to find out what they recommend for input voltage. If I need to add a resistor, I definitely will. I have friends that have ran these modules and coils wired the same as mine for years without any problems, but who knows.

e1956v!, I haven't spent too much time on here outside of this thread yet but was hoping to find you, haha. I joined up here after the first couple rounds of thinking we had this figured out and them back to square one. After several searches led me here I thought, I have been meaning to join for a long time and there has to be a lot of guys running these same parts, I better just ask the HAMB.

Definitely a lot of knowledge here and good ideas! Everything that has been talked about I have looked at and tested to the best of my ability. I appreciate all the ideas and suggestions! Hopefully we are coming to the end of this madness and can get to the last couple shows before the snow falls with you! I missed all the big events and shows I wanted to make because of this.

I'll let you all know what I hear from pertronix when they get back to me. Till then, keep cruising

Thanks again
Mike

 

I run a small-body HEI in my car, I have little space between that and the firewall. The cap itself is stock appearing. It was the cure to the ailment for sure.

I had considered a Petronix unit, I had trouble getting info at the time regarding which coil it should be matched up with. I should have been able to pick cafeteria-style off their web page. Their tech line at the time wasn't being answered and I was reading bad reviews about the product reliability, this was in 2015.

So what to do? I picked up a HEI eBay special.. truly brand-x with wires, they swapped the cap and coil to something I wanted. So far, so good and plenty of spark. It always starts instantly, if not sooner.

 

Battery cables have not been mentioned, but too small gauge can cause problems, especially if they are very long. Coils and resistors up under the dash do not get good airflow. Electrical components do not like heat. It seems most Pertronix problems are not due to inherent quality of the product. Small items like poorly crimped connections can cause big problems.

 

Proartguy, battery cables are pre-made battery cables from O'Reilly's. None of them have been extended or modified. I have another car that has had the coil under the dash for years without issue and a friend's model a with thencoil under the dash as well, no issues. The coil is now basically floating in the middle of the cavity between the firewall and dash, getting much more airflow than others I have seen. Still haven't had a reply from pertronix about the input voltage to the coil but have re read the instructions saying to remove the resistor with their coil.