I have a 1989 GMC C1500 350 TBI. Has new distrubitor. Also has msd a6L. i was driving on highway about 60 mph for about 20 minutes, stopped at driveway and truck died. I seen smoke coming from under hood. I opened the hoood and the distruibutor cap was on fire. It was an accel cap and rotor. I dont see why it would catch fire. Nobody i have taked to ever had this happen. What could of caused this?
The Accel cap and rotor I bought was a total piece of garbage with 'WAY' too big a gap between the rotor and the cap's posts.
This caused mine to smoke out by arcing all the contacts within a month. Mine didn't get to the actual on fire point, but if there had of been fumes around, well....
They shouldn't be allowed to sell them!
Same for the 'performance' yellow Accel wire set. Every wire broke the first time the plugs were checked which was when the 'new' cap also got tossed in the trash. (checked the plugs for fouling because of crap spark path)
I went back to an OEM cap and rotor and wires from the dealer 7 years ago now which are still working fine.
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's - Gone to the rust pile... Canadian Off Road Trips Photos: Non members can still view! Jan/06
Ive seen rotors with carbon tracks, and carbonized distributor caps, but dont remember seeing a fire in one. I respect the comments that Mike Romain has voiced and dont disagree with him.
But it also seems like I remember rare instances where fumes (gasoline in the crankcase, or even oil fumes) in an improperly ventilated crankcase can actually find their way past the distributor bushings and into the distributor head. If this were to happen, you might be able to light it. Anybody ever seen this happen?
on my race car, I had a situation where the ignition was effectively left "on" for 12 hours (car not running, but power to distributor), and the coil actually got hot enough to start melting the cap.
To this day, I'm not sure if we messed something up or ???
HEI dist in a 76 Camaro...
That is doubly odd, because HEI doesn't leave any current at all flowing through the coil when it is not getting trigger pulses from the distributor pickup. Sounds like a bad HEI module to me.
I have seen freshly sprayed with WD40 distributors catch on fire when they aren't wiped out or when the wires were sprayed while it was running.
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's - Gone to the rust pile... Canadian Off Road Trips Photos: Non members can still view! Jan/06I havnt done anything to the plug wires or cap and rotor for about
20,000 miles.
Ray
The word "yuck!" comes to mind.
I don't doubt you, but I'm guessing the real problem was with the HEI module and not the coil, because the HEI should shut off current through the coil under those conditions.
A picture is worth a 1000 words... The failure resulted because the ground strap was not installed. No secondary ground = really high resistance.
Usually they only run for 30 seconds or so.
Yep, happened to my 71 Firebird. The CVS clogged, and since the dist. seals were leaky, the gas naturally pushed through there, one spark, and stranded on I-75 with a LOT of excitement!!!!!!!
Thanks,Knifeblade...I know I may be senile, but not yet totally over the hill.
Good point. I'm now wishing I knew which module that was - stock, MSD, spare, my buddy's...
I usually pull the battery cable anyway for safety - it's a race car, so it has no neutral safety switch...
Ray
WTF?
This happened with the car sitting with the ignition switch ON, but the car not running. (we started the car, shut it off, had lunch, and much later I smelled the cap melting.)
It's a dirt race car - there's two ground wires on it. A big one that runs from the battery to the back of the cylinder head, and a little one that feeds my voltmeter. The car has a starter, alternator, distributor a voltmeter and an ignition switch. that's the entire electrical system.
AFAIK, the module still works. I wish I could remember which one it was so I could test it/toss it.
Ray
That's exactly what everyone says when they don't install the ground strap when they switch out a HEI distributor cap...
If the pole piece is lined up just right and there is voltage to the ignition coil/module, the ignition system will throw sparks even though the engine is not running. It's a rare situation, but it has been known to happen.
I'm talking about the stamped metal ground strap that should have been inside the distributor cap, fits under the coil frame and extends over to the harness plug, it is definitely missing in the pictures. Echlin part number RR-204;
ok, and now I'm going to have to admit that you may be right. Because it was three years and three engines ago, I'll be darned if I can remember if it was in there or not. When I bought the car it had a running 305 in there which I overheated *(a bumper through the rad will do that) so this was engine swap time. I can't remember if this was the distributor cap on engine 1 or 2, the 305 or the 350 that replaced it. This was the first year of racing, so I was having to fix and rebuild stuff daily just to keep the car running.
Digging through the pics I have, it looks like that was the cap & rotor and coil that was originally installed - I think it looked pretty new so we concentrated on other stuff like the fact the cage wasn't up to snuff and it had stock size wheel studs - most of which were loose...
I can say for sure that that ground strap is installed now - there were no leftover parts after the swap. :)
Ray Ray
An MSD is a common swap. Just because there aren't any left over parts, doesn't mean the swap or replacement was correct in the first place...
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's - Gone to the rust pile... Canadian Off Road Trips Photos: Non members can still view! Jan/06
So the circuitry powers the coil until the distributor shaft rotates, sending the pulses to shut it off. Remember, it's when the primary current is interrupted that the coil generates a spark, so when you left the ignition on but not running, the coil was receiving full primary flow. Gets plenty hot. Typical current could be three or four amps or more.
Dan
lol.
did you look at the pics? By swap, I meant cap and coil were tossed in the trash and another one swapped in place. I know THAT one has the little clip, and I could have sworn the other one did too, but I'm not sure because we chucked the whole thing into the trash.
The car currently has my buddy's old distributor, a Bosch cap and rotor, a free Accel supercoil under a stock cover, and an MSD module. I'd like to get one of those Davis DUI setups....
Ray
ok, but why would that never happen in a street car if you had the ignition on to run the radio but the car not running?
Ray
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