New Pertronix ignition, still doesn't run right

[redneck@mich.com]

I need some help here. I am about ready to torch this car. I have a 69 Corvette with a 350 and the thing was running smooth at idle, but if you goosed it, it would give you a pop. A friend suggested that the condenser was probably the culprit. Rather than go back to points and condenser, I decided it was a good time to go ahead and upgrade to electronic ignition. I went with the Pertronix Ignitor II and the Flamethrower coil. In addition, I have replaced the plugs, wires, cap, and rotor through all of this. It is now starting hard and seems like is kicking back. When it starts it makes a banging noise (predetonation?) on the right bank of cylinders. The left side seems to run smooth I didn't want to run it while making that noise for fear of doing some damage. I couldn't really time it. Am I getting interference between the wires or am I looking at a real mechanical problem? Any help would be appreciated
Thanks,
Jim

 

[Bob Chadwick]

Not to belabor the obvious, but I would go back and check the wires for correct order and to make sure they are secure, particularly on the bank that seems to be problematic.

 

[mvftw]

Play with your timing...

 

[cruisin-davey-g]

I need some help here. I am about ready to torch this car. I have a 69 Corvette with a 350 and the thing was running smooth at idle, but if you goosed it, it would give you a pop. A friend suggested that the condenser was probably the culprit. Rather than go back to points and condenser, I decided it was a good time to go ahead and upgrade to electronic ignition. I went with the Pertronix Ignitor II and the Flamethrower coil. In addition, I have replaced the plugs, wires, cap, and rotor through all of this. It is now starting hard and seems like is kicking back. When it starts it makes a banging noise (predetonation?) on the right bank of cylinders. The left side seems to run smooth I didn't want to run it while making that noise for fear of doing some damage. I couldn't really time it. Am I getting interference between the wires or am I looking at a real mechanical problem? Any help would be appreciated
Thanks,
Jim

Jim: I had a similiar problem with my "pertronix" unit: I did two things to make it work. 1) I doubled checked the connections between the Pertronix unit & the coil; and the connections to the unit itself; also, I made real sure that the mounting surface inside the distributor that the pertronix unit mounted to was clean.
and 2) Installed a MSD unit (that really woke it up).

BTW: I've been running one of those "pertronix" units since the mid 80's, before they were even known to the performance world; got it from the place that makes 'em in Calif. It still works good & is probably a much simpler unit than the Pertronix II unit.
I was told that mine was one of the first units produced for performance vehicles. Before that, these electronic units were used in industrial machinery & motor applications & still are.

Dave:

 

[JohnZ]

Double-check your wire indexing at the cap (18436572), and throw a timing light on it so you know where you are and re-adjust if necessary. Make sure you don't have the wires for #5 and #7 routed right next to each other - they're adjacent in the firing order, and can crossfire (induced current) if they're touching each other.

 

[Vette/Berlina-coupe]

-all of the above, plus...

-also check to make sure your Harmonic-balancer isn't aged to the point that its timing-mark is slipping (which makes it only possible to time by ear, --that is, fastest smooth-rpm, then back-off until engine starts without kick-back); --or worse, your timing-chain may be loose to the point that it is impossible to obtain a consistant timing-adjustment (to check: you can either pull the distributor-cap and observe the Rotor, or pull the entire Distributor and then insert a large-screwdriver down into the distrib.driver-slot, --then placing a large/socket-wrench on your front Crank-bolt, --turn Crank both directions while observing the Rotor or Screwdriver for degree of slop/play/lag between the direction reversals (ideally, there should be next to none to speak of, and your Rotor will have twice the play that is observed at the Crank-end of things, owing that the Camshaft is geared to turn at exactly half-speed of the Crank!)... ~Bob vH
:dance

 

[redneck@mich.com]

Thanks for the response. I'll have to check when I get home.

 

[Jack]

low voltage-resistor wire?

I dunno if this may be the problem or not ... but since you didn't mention it ... here goes.

I understand the pertronix requires a full 12 volts. I think the factory ignition power wire is a resistor wire that steps voltage down to much lower (around 8-9 volt?) voltage. I've seen other posts where this resistor wire-low voltage was something that must be addressed with pertronix. Maybe you've already taken care of it ... dunno. Hope this helps.
JACK:gap

 

[JohnZ]

Re: -all of the above, plus...

-or pull the entire Distributor and then insert a large-screwdriver down into the distrib.driver-slot, --then placing a large/socket-wrench on your front Crank-bolt, --turn Crank both directions while observing the Rotor or Screwdriver for degree of slop/play/lag between the direction reversals ~Bob vH
:dance

If you pull the distributor, there's nothing to stick the screwdriver into except the upper end of the oil pump drive shaft, which won't move, as it's driven by the distributor.

 

[AKRAY4PLAY]

Jim,
i don't have any experience with the Pertronix unit. but the smooth idle says to me the ignition is probably alright and the source of the agrivation is the carb jetting. i have seen a lot of older cars that with the same problems you are describing. a majority of the time it was an accelerator pump that went bad. a quick check is pull your air cleaner and move the throttle by hand while looking down the throat of the carb, i would suggest doing it with the engine off. if the carb squirts fuel into the venturies in a very noticable quantity and your spark plugs look like creamered coffee, never mind my post. hope you get it figured out soon, Brian

 

[Mpit69]

I have petronix unit and coil and you have to make sure new plugs are gapped at .045 instead of .035. Also make sure popping isn't due to sticking accelerator pump on carb, I had this problem recently. Disconnect coil capacitor also.

 

[redneck@mich.com]

I finally got a chance to get under the hood on Saturday. I found that the #4 and #8 spark plug wires were reversed on the cap. I corrected the problem and expected the car to start up and purr like a kitten. No dice. It is still making the loud clunk when you try to start it. I have the plugs gapped at .045 as recommended by Jegs, but I don't have any idea where the coil capacitor is or how to bypass it. Thanks for the help so far, please keep it coming.

 

[Jack]

Originally posted by redneck@mich.com but I don't have any idea where the coil capacitor is or how to bypass it. Thanks for the help so far, please keep it coming.

I dunno what a "coil capacitor" is ... maybe mpit69 meant "coil resistor"... I cannot say for sure on yours, but many have a resistor wire that powers the coil. In those, there are two power (pos) wires going to pos coil post ... one is 12vdc and comes direct from starter and is energized only when the starter is engaged ... the second power wire is a resistor wire (low-voltage)and is what the coil runs on after starting. Look on your coil positive post and see if there's two wires. If so, disconnect them & attach a voltmeter to each one individually. With switch in run position ... only one should be hot ... and it should read less than 12vdc (?around 8-9vdc?)... the other wire should energize only when starter is engaged (switch in start position) and it should read full 12vdc. If you have such a setup ... you probe the low-voltage wire down to its 12vdc source ... then run a regular (non-resistor) wire from that source back to the pos coil post. BTW, an old resistor wire looks just like any other wire to me.

On the other hand ... instead of a resistor wire ... maybe yours actually has a wound resistor ... those are usually a light, buff-colored ceramic gadget about 2-3 inches long with a coiled winding visible. ... If you have that setup ... just chunk/bypass it.

Either way ... probing w/ a voltmeter as I described will confirm what voltage(s) are at coil & when they're available.

I also suggest contacting pertronix to verify the low-voltage/resistor wire issue on your application. Maybe someone else here knows exactly what color wires yours are and where the resistor wire gets its source 12vdc?
JACK:gap

 

[AV8RSVT #1]

Try going to Pertronix Web site. They have A FAQ section on this unit and they talk about the problem you are having. They do talk about the problem possibly being the Coil Resister or the Resister wire that has been mentioned. Good troubleshooting by all.

 

[pws69]

but I don't have any idea where the coil capacitor is or how to bypass it.

I believe you are referring to the "noise filter" capacitor that is mounted to the side of the original coil. Pretty obvious if it's there and if it is, just unhook it.

I have another thought though.....

Are you sure your valves are adjusted correctly? If you have one a little too tight, that COULD cause that type of popping. It seems like you have eliminated everything else.

By the way, I also have a Pertronix in my 69 350 - using the same original wiring and I have had no problems.

 

[Alwyn678]

I went throught two Pertronix units..........Both were faulty.I had nothing but problems with both units. I sent it back bought a Mallory dual point distributor and I have never been happier.

 

[redneck@mich.com]

Got it running this past weekend. The distributor was one tooth off when I put it back in. Must have turned the oil pump when I took the distributor out. Runs good now. Thanks for all your help.