Ignition system woes {Still Troubleshooting}

Turbinepower · Last edited by Turbinepower on Sun Dec 11, 2005 6:42 pm; edited 2 times in total

I've fiddled and pondered this for some time myself... and finally decided it was time to talk to those more knowledgeable than I.

I have a 1971 Squareback, aftermarket carbureted, automatic. About a year ago it stopped running, so I regrettably parked it, lacking the time or money to work on her.

I've gotten the time now, so I've been one by one going through and checking various issues. I know I am getting fuel to the cylinders, and I know the starter turns the engine over very nicely.

So I looked more carefully at the ignition system. I get a nice 12.65 volts from the switch to the coil, and just replaced the points and condensor on the distributor. However, testing the assembly by pulling out a spark plug wire and attaching it to a properly gapped plug, then turning over the engine with the plug grounded against the block produced no spark.

This is obviously a problem, no?

So I checked as per Bentley and the Idiot book, by holding the coil wire's contact close to the block and turning over the engine, checking for arc. Still no go.

Am I just doing something wrong in the testing? I know it's a good coil, as I tried it with the one out of the Super Beetle we have that runs.

Any help would be greatly appreciated...

Thanks in advance!

Russ Wolfe · Posted: Thu Nov 24, 2005 7:37 pm Post subject:

You either have the points adjusted wrong, the coil is bad, or the distributor is not turning or is not grounded.
Connect your meter to the distributor side of the coil. The side the points connect to. with the key on, the meter should go from 0 to 12V as the points open and close. If it is 12V all the time, the points are not opening. If it is 0V all the time, the points or the distributor is shorted to ground.
Disconnect the wire from the distributor and connect a jumper wire to ground, from that terminal. Every time you unhook the groundng wire, you should get a spark from the coil wire.
_________________
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Turbinepower · Posted: Thu Nov 24, 2005 8:23 pm Post subject:

Russ Wolfe · Posted: Thu Nov 24, 2005 9:32 pm Post subject:

Yes, usually, it is a green wire.
_________________
Society is like stew. If you don't keep it stirred up, you end up with a lot of scum on the top!--Edward Abbey

Gary: OK. Ima poop.

Turbinepower · Posted: Thu Nov 24, 2005 10:11 pm Post subject:

Thanks, I just figured I'd make sure. Clear up confusions so I don't cause more problems than I solve, eh?

And you're also referring to grounding that same terminal, the one on the coil, in your later test?

Russ Wolfe · Posted: Fri Nov 25, 2005 8:39 am Post subject:

Yes
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Society is like stew. If you don't keep it stirred up, you end up with a lot of scum on the top!--Edward Abbey

Gary: OK. Ima poop.

Air_Cooled_Nut · Posted: Sat Nov 26, 2005 1:01 am Post subject:

I would recommend getting a Bentley shop manual. It's very helpful for this sort of stuff and MUCH more.
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Bobnotch · Posted: Sat Nov 26, 2005 9:47 am Post subject:

Also check the ground strap at the nose of the trans, as it could be broken, loose, or just covered with crap, and not making a good connection. It's worth a try, and only costs a little time. Very Happy

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Turbinepower · Posted: Sun Nov 27, 2005 6:15 pm Post subject:

Turbinepower · Posted: Mon Nov 28, 2005 4:53 pm Post subject:

Well, I tested going from the distributor side of the coil (Green wire) to ground as I hand turned the engine over this evening. I got a solid 12.6v. As I rotated it, this voltage varied, but never dropped below 10v. I rotated the engine over a good four or five times with the same result.

I pulled the distributor cap off and kept rotating, to check and see if the points opened and closed, and they sure enough were visually separating and coming together. I checked their gap just to make sure, it went nicely with a .40 feeler gauge as per Bentley. Just a little bit of tightness, no forcing or loose sliding.

So... I'm a little stumped here. I shouldn't be getting this result, but why am I getting it?

I'll check the nose grounding strap and the other test tomorrow afternoon, when it isn't threatening rainfall.

Russ Wolfe · Posted: Mon Nov 28, 2005 5:46 pm Post subject:

I t should drop to zero volts when the points are closed. There is a little braided ground wire in the distributor. Could it be that that is broken? You are on the right track. It does sound that you have a probelm with grounding in the distributor. Do the points look dirty?
_________________
Society is like stew. If you don't keep it stirred up, you end up with a lot of scum on the top!--Edward Abbey

Gary: OK. Ima poop.

Turbinepower · Posted: Mon Nov 28, 2005 7:47 pm Post subject:

Err, on a hunch, I just went out and looked at the distributor again.

Is it bad if the screw holding the condensor on basically bridges the metal contact terminal plate and the distributor housing? I know there's a bushing to keep it in place where the terminal goes to the inside of the distributor for the points to hook up to, but does that plate need to be kept out of contact with the housing?

Could this be my grounding problem?

Foxx · Posted: Mon Nov 28, 2005 8:13 pm Post subject:

Turbinepower · Posted: Mon Nov 28, 2005 8:17 pm Post subject:

Turbinepower · Posted: Wed Nov 30, 2005 5:49 pm Post subject:

Alright, I just spent two hours playing with it.

Opened up the Distributor, didn't see any obvious grounds. Didn't find a little braided wire either, Russ. So I can't really say if it's broken or not.

Cleaned the old grease off while I was at it, lubed it as per Bentley. Regapped the the points out of the car and in it.

Put it back in. Hooked up my voltmeter setup, from the Distributor side of the coil to ground. Everything else is left alone. Constant 12v throughout the whole rotation of the distributor.

On a hunch, unfastened the condensor from the side and isolated it away from the distributor body with a clean new rag. Got this:

Cylinder/Points/voltage
1/open/12.4
4/open/12.3
3/open/12.4
2/open/12.6

In between each, when the points were fully closed, I dropped down to .07-.1v each time. It varied, even if I didn't move the engine around.

Is this correct?

Russ Wolfe · Posted: Wed Nov 30, 2005 6:09 pm Post subject:

That sounds correct. It sounds like you have a problem with the condensor or its mounting.
BTW, I forgot I have an ignition manual on my web site.
http://classicvw.org/gallery/main.php?g2_view=core.ShowItem&g2_itemId=2240
_________________
Society is like stew. If you don't keep it stirred up, you end up with a lot of scum on the top!--Edward Abbey

Gary: OK. Ima poop.

Turbinepower · Posted: Wed Nov 30, 2005 6:13 pm Post subject:

I'm thinking the same thing; it's a brand new condensor, too. Odd that?

Also, I went back and with the condensor isolated did the other two tests. I get a spark from the coil wire and from an individual spark plug wire, but if I test it with a spark plug in the socket (Properly Gapped) I don't get a spark there.

Weak condensor already?

Russ Wolfe · Posted: Wed Nov 30, 2005 6:28 pm Post subject:

The spark plug needs to be grounded to the engine.
I am thinking that the condensor is bad, or the mounting screw is doing something.
_________________
Society is like stew. If you don't keep it stirred up, you end up with a lot of scum on the top!--Edward Abbey

Gary: OK. Ima poop.

Turbinepower · Posted: Wed Nov 30, 2005 6:43 pm Post subject:

I was grounding it to the same spot I was jumping the others to; my standard "grounding point" where I've wirebrushed down to bare metal on the block, and keep it clean.

I'll pick up a new condensor tomorrow, again; think maybe a nylon washer between the mounting screw and the mounting plate might help? I have some around the house.

Turbinepower · Posted: Sat Dec 03, 2005 10:06 am Post subject: We have ignition!

Or spark at least.

I think I had some really dirty connections and a couple of really loose ones that were the only ultimate problem; the replacement condensor I got to replace the original replacement had too short of a pigtail on it; in a bug it would have fit and worked, but in the T3 it's way too short.

So I cleaned up the original and put it back in. I have spark from the coil, a good strong blue-white one, and spark at the plugs or at least my test plug, though it's a weak yellowish amber one. So a new set of plug wires are in order?

Firing order for our cars is 1-4-3-2, right? Oriented like thus:?

Car front
4 1
3 2
Car rear

Right?

Basically, I am now getting spark at least in a test setup. I pulled all four in-car plugs, checked them and regapped them: the deposits on the ceramic insulator are all ashy grey, a uniform light ash colour. There is some oil on the metal parts, but not directly on the firing contacts. I'm thinking this is probably just because I've been turning it over and not actually running it?

Other than the oil the plugs are in good shape, so it has to be something between the plugs and the coil wire... I'll clean the contacts on the distributor cap and the rotor, and look into replacement plug wires.

Any thoughts?


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Ignition system woes {Still Troubleshooting}
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