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'76mintgrün'02

irritating intermittant misfire

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My car goes from running smooooth to sputtering and missing and running like CRAP. Timing set on BB at 1400rpm. Weber 32/36 with C.D.s prescription. New fuel pump and filter. 002 mechanical distributor (not new). Pertronix module installed (new). New plugs and wires, cap and rotor. I did find that the NEW wire on no. 3 was loose at the plug end and shortened it and re-inserted it with a little sil-glide. That seeeemed to fix it, but apparently there is another problem. I have not lubricated the distributor advance mechanism yet, but the engine runs rough at all rpm when the problem arrises.

I am suspecting the Pertronix unit. I installed it with spade connectors, to allow for points should it fail; so returning to points seems to be the next thing to try (as well as lubing the distributor).

Wide band install coming soon and I plan on plotting the advance curve to see what the distributor is doing.

Place your bets... Failing Pertronix?

Tom

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My guess would be a bad plug, wire, rotor, or cap. Sounds like one cylinder is just not firing. If a bad plug wire is grounding somewhere the spark isn't going where it is supposed to.

when a pertronix stops working it usually just quits, haven't seen one cause what you have going on in my experience.

That is just my guess so that is where I would start.

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All right. Thank you for your input.

I was surprised to find that the no. 3 wire was bad right out of the box and maybe it is not just the connection at the end that was bad. I will try hooking my timing light up to each of the wires and see if the spark is consistant while the misfire is happening.

One strange thing I did notice is that the copper terminals in the distributor cap have the usual black deposit, but only on half of the terminal. I have always seen an even coating across the whole terminal (with points). I have been wondering whether this is typical with Pertronix.

Tom

photo 013.jpg

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Do you still have the old dizzy cap? If so, place both of them side by side and make sure that the indexing tab is in the same position in relation to the contacts.

As far as I know, the cap comes in 2 versions that look the same at first glance, but have different contact (electrode) timing. This probably has nothing to do with your intermittent problem.

I'll bet TobyB knows all about this.

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Yes, I'll admit it, I save my old parts. I looked and the tab is in the same location. Same evidence of "off center" arcing on the old cap. I appreciate the insight and will research cap options.

Running well right now. Diagnostics on hold... Timing light on board. Waiting patiently for misfiring-sputtery problems.

Tom

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A timing light is a good way to see if a wire is carrying spark but if the spark is grounding to the head it will still travel through the wire, a good way is to wait until it runs like crap again and pull a wire at a time, it should run worse or die when you pull a wire, if you pull one and there is no real change then that is the cylinder that is causing you a problem.

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I used the "pull a wire" method to isolate the no. three wire when it was bad, but there is not one wire that differs from the rest while running rough now.

A friend once told me, "if you think it is a fuel problem, check the electrical... and then when your are sure it is the fuel system, double check the electrical." That said, it could be fuel related....

I am going to eliminate the pertronix RIGHT NOW and will check back with the results. I am pretty sure I have the right cap for the 002 distributor. It is a Bosch part number 1235 522 056 on a 0231 188 002 JFD4 dist. The only cap difference I read about had to do with early/late models and the indexing key is either an "innie or outie."

The off center arc marks on the terminals are odd, no?

Tom

Update: Back to points. Number one wire was bad also. Still missing, especially in 3k+ rpm. wonky distributor maybe.

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FunkyLaneO was correct. The number 1 wire was bad also. New wires coming from Kingsborne. The Bremi set proved to be CRAP. I will be putting the Pertronix back in and setting the timing according to the post I read yesterday, which should improve performance at higher RPMs.

Toby wrote, "Quote:

2,500 rpm only if you have a tii

DISTRIBUTOR!

If you set a tii distributor at 1500, it'll be too advanced at 2500.

And the whole curve will be too far advanced, too.

The mechanical- only curve has more advance in the weights, since there

is no vacuum advance to add its two cents and 15 degrees.

Now, having said that, you'll probably find that the DCOE's might not like

quite as much advance as the tii did, simply because the tii did such a good

job at fuel distribution. But you might end up pulling 2-4 degrees at most.

The real number I can give you is 36 degrees of total advance at

4500+

Yep, wound way out. That was a totally safe number with any engine

combination I put together under 12:1 compression.

Others have very similar numbers to match.

hth.

Thank you for the insight. Tom

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