Pertronix ignitor problem

[sallittjob]

Hey guys,

I just installed a pertronix ignitor in my 75 FI bus and am having a stange problem. The engine starts and idles fine, so I set the timing at 5ATDC and the idle at 800. Next i pushed the throttle to 1,500 rpm then let off. Now the idle hangs around 1,000 rpm? What gives? If i shut the bus off then start it again the idle goes back to normal. Anybody have any ideas?

[WhirledTraveller]

sounds to me like your advance is sticking. Maybe the petronix module is causing some friction where it shouldn't.
_________________
1977 Westy, Automatic. Big Valve heads, CS Cam.

[sjhotz]

Ill never buy another Pertronix again. Bought 2, 1 for my FI 76 bus, and 1 for my dual carb 72 bus. Both died on me in the middle of nowhere, one second I'm humming along next thing I know bam no spark. Turns out both "Flame Thrower" coils crapped out on me, both within a few months of each other. My mechanic mentioned another of his customers had the same issue. Pertronix has a crappy 90 day warranty. They refuse to help me. Then last week my mechanic calls, he has another customer with same Issue. Needless to say, I told him points or compufire or hotspark. Avoid any which require a special after market coil.

NEVER AGAIN!

[Glenn]

[sjhotz]

Welp it looks like Compufire takes a special aftermarket coil setup, no experience with it but i'm wary.

Why was hotspark highlighted in your quote, are they low quality? I was hoping the fact that the stock coil could be used along with no additional coil wiring would be a good thing, am I wrong?

[Desertbusman]

[sallittjob]

Thanks for the advice guys. I agree that maybe the advance was sticking because my wires are too tight but if that is the case then why would it reset after I shut the engine off and restart it?


Also, quick update... Since I put the point back in the bus has been running fine, until I took it out for a quick trip and now it has been randomly misfiring at idle. I tried several time to adjust the points and also pulled all plugs and cleaned them. Seems like one thing after another keeps going wrong lately

[Wildthings]

Have you put a few drops of oil on the felt under the rotor? This is how the centrifugal advance gets its lube. You need to make sure the breaker plate moves freely as well. It is "greased for life" which means it needs to be disassembled cleaned and relubed.

Your vacuum advance may not be fully returning to the idle position. Suck on the retard can and see if it holds vacuum. If you centrifugal advance springs are getting weak then once you rev the engine the mechanical advance may not be returning fully to the no advance position. This is why I advocate not setting the timing at idle, it is just not always possible to set the idle accurately this way. Set it at full mechanical advance at 28° BTDC at 3500+ rpm hoses off or set it statically at 7.5° BTDC.

[sallittjob]

[ned]

[Glenn]

Should of stayed with points.
_________________
Glenn
74 Beetle Specs | 74 Beetle Restoration | 2180cc Engine
"You may not get what you pay for, but you always pay for what you get"

Member #1009

#BlueSquare

[bugninva]

[Desertbusman]

[bugninva]

_________________

[Wildthings]

[busnerd]

I had this same problem and it turned out in my case that the pertronix supplied grommet and strain relief were too big and they rub ever so slightly on the vacuum advance plate which prevents it from consistently returning to "home". The fix is to trim the inside edge of the grommet and the large diameter part of the strain relief cone that fits into the grommet. Just take a pair of sharp scissors and cut a "flat" section into both. Then when installing the grommet and strain relief make sure the flat section faces down toward the advance plate. The flat gives enough clearance so that grommet isn't dragging on the advance plate.
Worked for me.... good luck.
_________________
Clarke B.
samba member # 3245
'78 Westfalia Dakota Beige
'64 Camper

[Glenn]

[sallittjob]

Busnerd, this is a good point you bring up and I will try to trim my grommet as well.

Ok, so I just want to explain some of my "can't sleep, trouble-shooting the bus in bed" (think of the picture of that guy in the muir book) thoughts.

So, I first think that my misfire problem with the points may be due to the fact that I leaned the idle mixture out on the airflow sensor after I installed the pertronix, after I went back to the points I forgot to re-adjust. It seems that this would be a good explanation because the problem only occurs randomly and it typically only misfires at idle (if I'm correct AFM bypass does not affect the mixture when the engine is revved only at idle. Next, (if the grommet is not the problem) the FI system calculates engine speed from the wire connected to the 1 terminal on the coil. Is it possible that the signal from the pertronix is different than the signal from the original point so the computer is not returning the engine to idle? I pulled the plug off of the coil for the pertronix while the engine was revving high, the engine immediately began to die, then I plugged it back on and the engine idled properly.

[bugninva]

[sjhotz]