Okay. '59 Cadillac. Original 390 rebuilt a while ago...like 250,000 miles ago. Ran great up until last fall. Intermittent miss from both sides of the mill. Pulled the trans, had it rebuilt cuz it was slipping. Put trans back in and started trouble shooting the engine problem. It's true dual exhaust with functional lake pipes, so I can definitely tell that the miss is coming from both sides when it actually does it. So far, I've replaced the coil, dizzy cap and rotor, and the ignition switch. Me and Scallop53 and Barnyard pulled each plug wire one at a time, and each one made a difference in the way it was running when it was idling. We also sprayed down the plug wires, dizzy cap, and coil while it was running and there was no change, I am running wire looms though, so the water test was a little incunclusive on the plug wires. It's still missing. It comes and goes in surges, and every once in a while, the car just shuts itself off whenever it feels like it. When this happens, I put the lever back in neutral, hit the key and it fires right back up again. It seems to do it more while under a load, but you can still hear little pops every once and again while it sits and idles. Also, I've pulled all eight plugs, and none were fouled...actually they were all kinda white. The car still has some of the same gas in it from last fall. Also, I am running a Pertronix pointless ignition module in the dizzy. The motor was rebuilt bone stock, with the exception of an overbore of .0030 and it has dual quad Carter AFB's on it on a Weiand aluminum intake. So the question is, is this being caused by bad gas? Is my Pertronix taking a shit? Should I replace my plug wires without the looms and see if it makes a difference? Should I yank the Pertronix and put points back in? If it is bad gas, could I dump a can of Heet into the tank and hope for some positive results? Please help if you can guys...this one's beginning to drive me up the wall....Thanks in advance for any ideas...
ive had problems with pertronix before now i use a ford duraspark 2 pick up and an hei moduale works great
Do these symptoms soud like Pertronix issues? I've heard of people having problems with them before, but I've also heard that they either work or they don't...meaning that the car wouldn't run at all...
My experience with electronic ignitions has mostly been it either works right, or doesn't work at all. I've installed dozens of Pertronix ignitions and never seen a problem with them. But...A buddy recently brought me a problem exactly like yours with the HEI in his Chevelle. Out of desperation, I replaced the module, no more problem. With the Pertronix it's easy enough to rip it out, reinstall the points and condenser, and see if the problem goes away.
Cool...thanks for the input...now I just have to remember how to put the points back in...The pretronix has been in there for a while, and unfortunately, the directions have gone MIA...
Hey CadillacKid I have had problems with Pertronix before. The plugs being white might be a lean burn condition which will give you a surge at light throttle as well-check your fuel pressure and richen up your mixture to see if it changes things.
and put wires on it, ou've done the rest of the ignition. Wires will tend to leak more under a load because of increassed resistance in the plug gap as cylinder pressure increases. It's the same effect that requires you to run less plug gap when you are using a supercharger of turbo. Don't skimp on the wires in such a big car.
Does a '59 Caddy have a "dogbone"? The porcelain piece about 3/4" of an inch wide and 3 inches long? The dizzy wires run into it? If so, there's your problem with the Pertronix. There is nothing wrong with the Pertronix...I put Pertronix on my Stude and kept the dogbone in place...it would do the same thing...the Pertronix instructions tell you how to "go around" the dogbone...I did and eliminated all electronic problems... R-
With 250,000 miles on it, it's conceivable the timing chain has stretched so much that it's jumped a tooth or two.
You said 250K since OH, right? Compression test... Is there a shop that has cool svc writer/techs & will let you bring your car in to scope ign (while you're there) & let you see traces on individual wires? I never got enough practice to get real good at using that for diag, but some of the older time techs (worked before OBD & EFI) can tell a lot about what's going on in combustion chamber by 'burn line' on trace - whether it goes up or down as it tapers off, if it has a lot of 'bounce' or 'hash', as well as KV value. If the comp looks good, it may be cheaper to spend $75 on an hour of diag (if you hook up w/ a good tech) than spend $$$ throwing parts. Boy, I wish I had a 4 gas & ign scope here at the house.... bill out
ditto that. when i stabbed the nailhead in my buick, i installed some used accel wires i had laying around to get it going, left them on for two years without thinking about it any more, they "looked" fine, but the engine was getting tough to start in cooler weather and idled rough, this with a MSD 6 box, swapped to some fresh 8.5 msd wires and i swear it must have picked up 20hp or more, fires on the first crank and idles much smoother now.
I agree. Ignition problems deliver dark wet plugs. I'd suspect a fuel delivery problem from what you've said so far.
Thanks guys for all of the input....I was thinking it might be running bit lean...but I thought that usually a lean miss will happen more in high rpms?...I'll fatten the carbs up a little and see what happens....that after all is a fix that doesn't cost anything! Unfortunately, I can't adjust the fuel pressure...stock mechanical pump. My timing is probably retarded just a little bit too much also, which was the reason I was thinking that plugs were burning white....I'm gonna bump the timing up just a hair and check the plugs...after that, I'm gonna change me some plug wires and see what it does...
Okay...put new plugs and wires on it...no change. Still intermittent missing. And I eliminated the balast resistor when I put in the pertronix. I think I have some sort of fuel problem, whether it's bad gas, my fuel pump not putting out enough pressure (it is only about 6 months old though), or one of my carbs is screwed up, I don't know yet...I still might try changing it back to points ignition, but I don't think it'll change...none of the plugs are fouling out... I put a bottle of Heet in it today...I'm gonna run it around and try to get a couple of tanks of gas though the thing...if it keeps doing it, then I guess I can rule out the bad gas thing and move on to the next...I do have a Holley red electric pump sitting on my shelf too...hmmm...
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