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Discussion Starter #1
Hi All,

My Son and I have been racking our brains trying to figure out a new issue that surfaced on his 1965 289 Mustang. The first time this happened, the engine just died (my son was driving down the freeway so luckily he was able to get it over to the side of the road). Sounded a lot like no fuel. Had it towed back and started working on it. Fuel pump (which is fairly new) seemed to be pumping fine, and there is fuel in the carb. bowl (pulled the top of the carb off to check the bowl). Squirting starter fluid in the carb wouldn't get it to run but the engine does hit so it "almost starts." We had new wires, cap, rotor and points installed previously so we didn't think that was the problem. Checked the points gap and it was way too narrow. Fixed that...still no joy. Put an old coil on (from my Mercruiser boat) ... still no luck. Pulled the points and put the old ones back in and it started and ran like a champ. Figured it was the new points and the problem was solved. Drove it about 20 miles and on the return trip, the same problem surfaced.

We have it back in the garage now trying to figure this out (again). Voltage on the + side of the coil seems to be around 7 Volts although when we get the engine running, it seems to be running between 10-12 Volts. We put the old cap and rotor on (still with the old points) and cranked on it a bit and after a bit, it started. We don't feel like the problem is corrected. We've been watching the voltage on the + side of the coil to see if maybe voltage from the dash is cutting out but it won't die now.

This feels like an electrical problem (esp. given the fuel bowl is full and when the problem surfaces, we can't get the engine to run off starter fluid down the top of the carb).

Just wonder if any of you VMF experts have suggestions on next steps. I'm thinking either we have a flakey coil (that fails when the engine heats up) or a flakey ignition switch (or under dash wires). The coil doesn't seem likely as the boat coil wouldn't get the engine started when we hit this problem the first time. The boat coil is off of a 1984 4 Cyl Mercruiser so I'm not sure if that would have made a difference or not. Oh, when the engine hits this situation, I put a jumper between + on the battery and the + side of the coil and it didn't help us get the engine started. We were kind of hoping we could get this to fail with the volt meter on the + side of the coil but no luck so far.

This one has me stumped.

Pete
 

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make sure that the nuts are tight down on the + and - side of the ingnition. 7 volts is strange thought if you have under 12 it wont crank.
 

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Frustrating issue. One thing I would check is the health of your disti. If it is worn, and has play it can drive you crackers.

If it is bad, you have some options. You can by a remanufactured one for $60 or do an upgrade that you won't regret and install electronic ignition. I have heard that the pertronix conversion works ok, even with worn disti's, since it is a magnetic pick-up. That would be around $80. Or just buy a whole new disti with electronics ready for go for $250.
 

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You have an electrical problem.
 

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Discussion Starter #5
Yeah, I forgot about the resistor wire until I looked it up in the manual. With a functioning resistor wire, I'd have thought I'd see about 7 volts consistently on the + side of the coil after the engine is started. When we hit the problem condition, even a jumper of the + side of the coil directly to the + side of the battery doesn't fix the issue so this seems like a huge clue. I'm just not sure what it means though. In theory, it means the coil is not generating adequate spark so, assuming this is an ignition problem, its got to be either the points or the coil. We've swapped in the old points, cap, rotor so I'm leaning towards this being the coil.
 

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Discussion Starter #6
We got a chance to tear into this further yesterday. The engine at this point, started and ran ok in the garage so we went ahead and put in an old coil (from the boat, as mentioned earlier). We went under the dash and found the pink resister wire. It seemed intact. We put an ohm meter across it and it seems to be running about 1.8 Ohms which seems reasonable from what I can tell. I'm still seeing about 11 volts on the + side of the Coil with just the ignition on so it doesn't seem like the resister wire is "resisting" very well.

Anyway, we let it idle in the garage and after about half an hour and the problem surfaced (engine died, hard to start etc.). A jumper from the battery to the + side of the coil again doesn't help (and I'm still getting 11+ volts on the + side of the coil anyway). Since we replaced everything in the ignition system except the condensor, I put the old one back in and that seems to have fixed it. Engine idled for about an hour w/ no problem. Drove it around and it seems fine. I wonder if my insufficent resister wire is causes the new condensor to short to ground when things get hot. An ohm meter on the failing condenser doesn't show a short and seems to ohm out about the same as the one that's in there now. Wow.

We want to go to solid state points anyway but I hate to introduce new variables when I'm not completely sure I've solved the last issue. Where does one get replacement pink resister wire?
 

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You may have replaced everything in the ignition system but you never mentioned the ignition switch ( probably over 40 years old and shot ) I'd look into it, could be very erratic and lead to insanity over time.
Good luck!
 

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Discussion Starter #8
Good point on the ignition switch. In trying to get the problem to reproduce, we've wiggled wires on the switch and everything seems rock solid. Also, when the problem happens, we're getting a full 12 volts on the coil so we've kind of ruled out the ignition switch at this point. We've had this car for less than a year so we're not completely sure the switch is original so its possible its not 40 years old. Not sure.

Good point but we're thinking we've ruled that component out at this point. I'm open to being shown the error of my ways though :)
 

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Another "possibility", although unlikely, would be to check a few grounds. Primarily the contact on the block and alt/gen (depending on what you've got) also, voltage regulator just came to mind...
Honestly though, if you're planning on major ignition changes, I would go ahead and make the changes. I get the urge to find the 'problem' ahead of time but I wouldn't spend the time and money at this point just to take it all out and start over anyway. As you mentioned, some of the parts may be newer than others and you will never know what the PO did. I vote for starting fresh now!! :)
 

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Discussion Starter #10
One thing that Black65 mentioned earlier about investigating the ignition switch, got me thinking. The fact that I can't see less than full voltage anymore on the + side of the coil is puzzling. When this problem first surfaced, I did see ~7 volts at the coil (which is what I should be seeing with just the ignition turned on). As I understand it, when you put the ignition switch into start mode, the resister wire is bypassed providing a full 12VDC at the coil until the engine is started. I'm wondering if the ignition switch is "stuck" where basically this bypass mode is enabled all the time. Hmmmm.

Here's a question...when I have the key switch set to "accessory mode", the ignition lights are lit (oil pressure etc.). Is that normal behaviour? I was expecting accessory mode to only activate the center post on the back of the ign. switch where we have the stereo connected. I do see another lead from that post going off into the instrument cluster. Its possible someone mucked with this wiring. If I had a bad resister wire, I would expected the resistance to get higher (resulting in less voltage at the coil during non start ignition only mode).

We're going to slap a Pertronics ignition on there so this will hopefully become a moot point.
 

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We're going to slap a Pertronics ignition on there so this will hopefully become a moot point.
... and a new ignition switch! LOL!!

I'm just playing around, I hope you figure it out! I'm curious to see what the problem is!

PS. Is there a neutral safety on the car? That could have a faulty contact as well and really make you crazy!
 

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wonder if they ever got this running? , It's a 5 year old thread.
I would like to know more about the tire size on Black65's car however
 
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