Timing the engine...

[167luckycharm]

this afternoon with my timing light and noticed that the engine was running rough. Disconnected the timing light but the engine continued to backfire through the carbs, pop, and cough. The valve adjustments were done right after I retorqued the heads, fresh gasoline in the tank, and the static timing was checked at 7 degrees BTDC. After cleaning the idle jets on the dual 44IDF's, (which were clean by the way), I hooked up the timing light and started it up again. Same problem existed, but I found that there's an occasional spark occurring while the pulley marking is NOT at the correct position. The timing light shows that the advance mechanism is working while the engine rpm increases, but once every 3 or 4 seconds the timing light will flash at 6 degrees BTDC while above 2000rpm. The max advance is set at 30 degrees BTDC with the engine above 3000rpm. I changed the distributor cap with my new spare...same problem. I changed the distributor with the spare too. It has a new set of points, while the first one has a CompuFire installed in it. Would a coil give off an errant spark? The tach was disconnected and the problem continued. I'm not sure if there's a bad connection at the ignition switch or somewhere else. It's too late at night to go over to the garage and rev it up right now. I'll check back on this board in the morning if anyone can help. The engine will run smooth while the sparks are occurring at the right interval, but when they don't...it runs like it's idle jets are clogged. Weird! Thanks in advance! John.

[Gene-C]

I don't think that the coil would be the problem. The coil only sends a spark when the magnetic field inside collapses. This is the job of the point or electronic ignition. My guess would be that you condenser might not be working properly. I would carefully check all the wiring between the coil and dizzy to see if there are any shorts or loose wires. that's all I can think of. But I'm not expert. Or at least I don't think I am.:laugh1:

[newmanx59]

I would convert the ignition back to the stock points and condenser. It's hard to troubleshoot something you can't see and you can't see what's happening in the Copmufire. The points are mechanical, when they open you get spark. I would also seperate the plug wires. You could be seeing some crossfire from one wire to another. Keep us posted on your progress.

[UncleBob]

Was your spare distributor complete, or did you swap condensors? That is a wierd problem. I'm leaning towards electrical. If I was seeing this problem, and it continied with my spare distributor, I'd start by replacing ignition connector at coil, and ensuring BOTH connectors at coil were on tight, and that the nuts were holding down the brass male connectors good. If problem continued, I'd bypass ignition entirely by running a 12V jumper straight to my coil.

[Gene-C]

You said the carbs were clean but did you pull the tops off to see if there is any gunk in the bowls? Once I hosed off my engine after a day in the dirt then put it away for about a month. Water had gotten inside the carbs and turned to snott.I had to have them rebuilt just to get it running right again. Now I put shower caps over them when I clean the engine. Live and learn.

[newmanx59]

The more I think about it....there is no way for spark to happen on a wire when it's not supposed to unless it is a crossfire situation. The rotor has to point to the spark plug wire terminal in the cap for spark to travel from the coil thru the rotor to the spark plug wire terminal in the cap that supplies the spark to the wire. The rotor only points to the spark plug wire terminal in the cap when it's supposed to fire the plug. Am I missing something?

[UncleBob]

[QUOTE="newmanx59"]The more I think about it....there is no way for spark to happen on a wire when it's not supposed to unless it is a crossfire situation. The rotor has to point to the spark plug wire terminal in the cap for spark to travel from the coil thru the rotor to the spark plug wire terminal in the cap that supplies the spark to the wire. The rotor only points to the spark plug wire terminal in the cap when it's supposed to fire the plug. Am I missing something?[/QUOTE] Yeah, a crossfire sounds very likely, but what if the ignition wire wasn't making good contact with the coil? I suppose if the non-contact was happening rapidly enough, you could get more than one spark when the rotor comes close to terminal, and again before it gets too far away.. I'd be interested in seeing if the problem appears on the opposite cylinder bank (3+4) side. This would rule out an ignition supply voltage issue and would most certainly point to an arcing plug wire on the 1+2 side.

[croakintowd]

Howdy, You could be crossfiring if your secondary wires parallel each other for a few inches. If you have a renegade "Make and break" wiring problem (Bad connection in the primary wires) You could send a random spark to a wrong cylinder, as the spark would just jump from the end of the rotor to the path of least resistance, which could be to another cap contact, or a ground. Carbon trails in a cap will help things misfire. I once chased a similiar problem for a whole day on an old Chevy I had a million years ago. It would idle, but anything over 1200 RPM, and it was popping and backfiring. After I spent the whole day replacing everything I could think of, it turned out to be the spring on top of the rotor had broken and fallen off. I handled that rotor 10 times that day, but never noticed the missing part. Even more odd was the new replacement rotor had the same problem. It was made with no spring. What are the odds? Now that I've said all that, here's a disclaimer. I have little to no experience with VW engines. I understand that a leaking intake gaskets and seals can lean things out and make the engine do odd things. So, good luck. Put a test light on the coil, with the engine off and the ignition on, and wiggle wires to see if you can get it to flicker. Something is telling the coil to generate a spark. Please let us know what you find. It's good info for all of us. Good luck,

[newmanx59]

I guess it could also be something making and breaking in the coil and God knows VW coils are prone to failure. The last VW coil I had fail did cause the engine to backfire and misfire before it failed completely. This is an interesting delemma, I'd love to get my hands on it.

[Lee]

This is one of the most interesting threads we have had in a long time. I'm just glad it's not me this time! :laugh1: I like the ideas everyone is putting out there. Spark plug wires are a definate suspect, as I have seen them do some very strange things. On a side note, it's funny how Chrysler named one of its cars the "Crossfire". Is that an inside joke among those who know? I also like Uncle Bob's idea of bypassing the ignition switch and running a 12V + lead straight from the battery to the coil for a test. Switches can get flaky, and it would be good to eliminate it from the equation. Good luck! I can't wait to find out what the culprit is!

[newmanx59]

[QUOTE="Lee"] I On a side note, it's funny how Chrysler named one of its cars the "Crossfire". Is that an inside joke among those who know? [/QUOTE] That's funny, The Chrysler Crossfire crossed my mind when I suggested the crossfiring plug wires.

[167luckycharm]

Hi all! Wow, that's a lot of replies! Two help clear up some thoughts, here's some issues; Both distributors are 009's. The one was on the engine from day one has the CompuFire module, no condensor needed. The spare has a fresh set of points and the condensor is a little old. Both have new caps and rotors that have about 1000 miles on them. None appear to be cracked and they each have the spring under the center carbon rod. Both rotors are good. All parts except the CompuFire are genuine Bosch. Both coils are Bosch. The plug wires are Accel 8mm installed earlier this year. When I first ran these NGK BPR6ES plugs new in July 05, the car ran great. While I had the engine out last week, the plugs were pulled and found to be blackened. Last time the car was run around the block before I yanked the motor, it was running rough and backfiring. Now that's it's all back together again looking shiny and nice, it still does not run right. Here's what I tried today; Removed all the plastic separators from the plug wires; still ran lousy. Hooked up a direct wire from the B+ on the generator to the +side of the coil; still ran lousy. Replaced the coil with another spare blue coil (used but in good shape); still ran lousy. Checked the #2,3,&4 plugs with the timing light; they all lit up when they were supposed to. Clipped the inductance pick-up clamp of the timing light to the #1 plug wire; timing flash occurs randomly at a wrong position, but mostly flashes at the correct position. Yep, still runs lousy. So I shut it off(again). Hooked up a multimeter to check if there's poor connections anywhere near the coil; all are good. Crawled under the car to see if there's one of those Gremlins from the movie hiding on top of the transaxle. Must be wearing a cloaking device 'cause I can't see it. With the solid trans mount installed and all the IRS arms and axles connections, I didn't think I needed to install the transaxle ground strap. The multimeter showed a good connection between the housing and nuts on the nose cone mount. But keep the remedies coming. I'll be back in the garage until this evening. My wife has their company Christmas party tonight...we'll be there but I think my mind will be occupied with this dilemma. I'm sure we'll figure it out. I'd rather be this fellow :driving: But for now, this is me :help: Thanks in advance! :hello: Aloha!

[UncleBob]

So, what happens if you swap the #1 and #2 plug wires? Or, are your wires long enough to swap the #1 and #4 wires? Does the gremlin follow the plug wire?

[newmanx59]

I would also try installing a new set of plugs. When I was doing the tuning on the new engine in my Manx it started popping and backfiring. I took the Webers apart and cleaned them again,etc ,etc with no luck. I changed the plugs and the problem went away (fouled plugs). The errant spark may not be causing your problem, it may have been there all along. If there is no compression or fuel when it fires, it won't cause any problems.

[167luckycharm]

So far, here's what I've found... The #1 plug wire was replaced with a different brand (empi) and it still had an errant spark. I re-installed the original wire and left the plastic separators off until I can figure this out. Replaced all four spark plugs with the same NGK BPR6ES. Gapped them to .032", and re-checked the timing with the light. Engine still has the rough off-idle performance. Pulled off both carbs and cleaned them out with carb cleaner and compressed air. All jets and orifices were thoroughly cleaned. Only found a little flecks of dirt in the bottom of the float bowls. Float adjustments were ok and no dirt was found in the top cover brass screen filters. It's late at night by the time I bolted the carbs back on, so I'll do the engine check tomorrow. I'll sync them before the engine is cranked up. I'll post my findings soon after... Aloha!