Strange problem, Pertronix maybe? Options

[Coy]

Okay I have a 74 2.0 with Hydraulic lifters. I’m running a 050 distributor with a Pertronix electronic ignition and dual Webbers. It’s been running well for about 7 years with this setup. I put new Triad exhaust on it earlier this year and it's kind of loud. (IMG:style_emoticons/default/biggrin.gif)

Earlier this year it started backfiring and popping and it sounded like maybe I had a collapsed lifter. Ends up I had two partially collapsed lifters but now I’m wondering if that really had anything to do with this problem. Anyhow, I got it all fixed and timed and it seemed good… smooth idle at 1200 RPMs with lots of get up and go for a 4 cylinder. I'm the happiest man in the world!

Then all the sudden the next day, it’s running crappy again; idling at about 800 RPMs and popping every once in awhile through the carbs going down the road. It pops every once in awhile through the exaust too... but maybe it's just feedback from the Triad exhaust, I'm not really used to it yet.

I thought maybe I might have some water in my gas, so I tried some Gumout fuel drier. I took it for about a 30 mile drive and when I got to the next town it was idling smooth at about 1200 RPMs no more backfiring. I'm the happiest man in the world again!

Stopped to top off the gas and when I went to shut it off it over ran like the timing was off. Started it right up and it was idling at about 300 RPMs and kind of shuttering, but it still seems to smooth out on the freeway.

Drove home to intermittent popping and farting and idling at about 800 RPMs before I put it in the garage and shut it off. Messed with it a bit, but it was idling smooth again and reved smoothly.

Next day I drove it about 80 miles. I stopped about 3-4 times and it was idling somewhere up and down between 300 and 1200 RPMs every time I shut it off and restarted it. It occasionally backfires, but still runs really great out on the highway.

Any guesses based on that description? Has anyone else had similar experience with Pertronix? I’ve heard that they can both 1) slowly shit-out on you or that they can 2) just stop working and leave you stranded on the side of the road all of a sudden.

The distributor seems tight and the rotor snaps back when I test it, so I think it’s good. Is there any way to test the Pertronix besides just buying a new one?

I didn’t install this electronic ignition, so I’m not even sure how it works. The backing plate still looks to be in tact; can I just get a set of points and condenser and test the distributor itself to see if it’s going bad all by itself?

Does anyone think this sounds like carb trouble?

Your collective genius is greatly appreciated.

[kenshapiro2002]

Make sure the condenser isn't touching the tin.

[blitZ]

If you are running a Pertronix, then you don't use the condensor. I doubt the Pertronix is the problem, it's just a switch. It either works or it doesn't. You might give the distributor a good clean and lube, possibly the advance plates are sticking.

[cary]

Old school ...............have you checked the timing?

[Coy]

Yeah, timing was set correctly, but it does seem like a timing issue to me...

There is no condenser with this setup. That's what I was wondering... can I just drop in a set of points and condenser to check the condition of the distributor?

It seems to me like a carburetor problem would be more consistent doesn't it?

[Spoke]

I had similar idle trouble with my dual Webers and turns out the carbs loosened up on the manifolds and was sucking air. Tightened them up and they were fine.

[J P Stein]

I had a Pertronix problem. A progressively fouler running engine. After checking everything under the sun (and the compression test came up low), I found that the black wire was pulled up tight agaist the magnetic post that fits over the dizzy shaft. It had worn through the insulation & more than half way through the wire......oops. End of that problem, but it didn't cure the compression. Rebuild time!

[Coy]

I had similar idle trouble with my dual Webers and turns out the carbs loosened up on the manifolds and was sucking air. Tightened them up and they were fine.

The carb was loose on the manifold, or the manifold was loose on the engine or both?

[Spoke]

I had similar idle trouble with my dual Webers and turns out the carbs loosened up on the manifolds and was sucking air. Tightened them up and they were fine.

The carb was loose on the manifold, or the manifold was loose on the engine or both?

The manifold was tight on the car but the carbs had loosened up. Because every time the engine vibrated the carbs would suck in a different amount of air and would idle differently. Spraying the manifold with carb cleaner while running isolated the problem.

[Coy]

I had similar idle trouble with my dual Webers and turns out the carbs loosened up on the manifolds and was sucking air. Tightened them up and they were fine.

The carb was loose on the manifold, or the manifold was loose on the engine or both?

The manifold was tight on the car but the carbs had loosened up. Because every time the engine vibrated the carbs would suck in a different amount of air and would idle differently. Spraying the manifold with carb cleaner while running isolated the problem.

That's a great suggestion Spoke. Thanks!

[ThinAir]

The symptoms of backfiring - especially back through the carbs - sounds like my 73 2.0 liter when I first got it. Picked it up in Seattle and drove straight through to Bakersfield before stopping for a few hours of sleep. Everything seemed fine when we shut it down, but we wondered who had swapped engines on us when we started it up again.

We had backfiring through the carbs along with low RPMs and running rough. Timing was not off, but it ran rally hot trying to get over a mountain pass and we actually had to turn around and return to Bakersfield. A valve adjustment helped and we got home to AZ, but then determined that we were the victim of a cam that had gone flat on us. I hope that's not the case, but with your hydraulic lifters it might be possible that they are masking such a problem as they "self adjust".

[Coy]

mmm. That's actually my fear as well. (IMG:style_emoticons/default/sad.gif)

[computers4kids]

Hi Coy!
What about a partially clogged fuel filter? Sediment in the fuel bowl....clogging jets periodically. Sticky needle valves...don't have any experience with webers but just an idea.
Mark

[Coy]

Hi Coy!
What about a partially clogged fuel filter? Sediment in the fuel bowl....clogging jets periodically. Sticky needle valves...don't have any experience with webers but just an idea.
Mark

Yeah, one can hope, huh Mark. I'm going to mess with it some more tomorrow.

[orange914]

If you are running a Pertronix, then you don't use the condensor. I doubt the Pertronix is the problem, it's just a switch. It either works or it doesn't. You might give the distributor a good clean and lube, possibly the advance plates are sticking.

my recent experiance with the pertronix help line i asked just that and the tech confirmed that they can and do sometimes have drivability issues. google for the pertronics tech line and have him walk you through some test

[Tom]

You said you have hydraulic lifters, are they noisy? Is your oil pressure good? Maybe not pumping up tight?
I also have hydraulics and if I let it sit for a few weeks, it shakes and idles rough until they all pump up and they are loud until they do. You indicated you had a couple of collapsed lifters. How did you fix that? I hear that new lifters can mess up an old cam.
With the amount of carb problems I have been reading on here, I would suspect the carbs are getting plugged up jets.
Tom

[Coy]

You said you have hydraulic lifters, are they noisy? Is your oil pressure good? Maybe not pumping up tight?
I also have hydraulics and if I let it sit for a few weeks, it shakes and idles rough until they all pump up and they are loud until they do. You indicated you had a couple of collapsed lifters. How did you fix that? I hear that new lifters can mess up an old cam.
With the amount of carb problems I have been reading on here, I would suspect the carbs are getting plugged up jets.
Tom

Hey Tom,

I couldn't figure out what was going on, so I took it to Randy at Silverton Air Cooled Motors here in Oregon. He's not on the board (technophobe I think) but he has three 914s of his own. He specializes in VW and mostly VW buses, many of which, apparently came with hydraulic lifters. He couldn't fully adjust two lifters so those two he pulled (he replaced the pushrod tube seals while he had it apart, and did the whole job without pulling the engine). On inspection they looked pretty rough. One had worn on the bottom where it contacted the Cam. I asked about the Cam and he said it could be worn too, but probably not critically, since the adjacent lifter adjusted just fine using the same cam lobe. It runs really strong and smooth when it's all working.

It used to have a funny knock when it idled, but that is now gone (sounds really good with the Triad). If I run it every day it doesn't clatter at all when I start it. If I leave it for two or three days it will clatter for about 10-15 seconds the first start, while the lifters pump back up; that hasn't changed.

I talked to Randy and he seems convinced that I have water in my fuel. He said that clogged idle jets would be clogged all the time; they wouldn't clear. The timing is on the nut and the Pertronix seems good since it runs and idles great when it's working... But I'm still kind of suspicious about that. I wrote Pertronix.

He said he's seen this a bunch and that water can kind of roll around the bowl and block the idle jet (but not pass through the jet because of it's heavier viscosity and surface tension).

I put a bottle of Gumout into a full tank and plan to put another treated tank through, but it just gets too damn good a mileage... I work from home and still haven't run a tank out in almost a week. I don't have that kind of time and it's been rainy... Blah blah blah. I guess I'll just keep fuching with it. I think that's what these cars are for, huh?

Good luck with yours man! I'll let everyone know if the gas treatment works.

[stugray]

I had a similar problem with my Ghia driving across country.

It would fire right up and run for a while then start backfiring and losing power until I had to pull over.

I'd mess with it for a while not finding anything and then it would fire up again and drive for 100 miles, then it would breakdown again.

Eventually I figured out it was something in the gas tank clogging the fuel line.

Once I took the tank out, cleaned it, and blew out the fuel lines, the problem was gone.

Stu

[Coy]

Pulled the fuel filter and blew about 3 tablespoons of water into a glass bottle. Added more gas drier and took it for a spirited drive in the country!! (IMG:style_emoticons/default/driving.gif)

Yeah Baby! (IMG:style_emoticons/default/aktion035.gif)

I think she's back!

[Drums66]

Pulled the fuel filter and blew about 3 tablespoons of water into a glass bottle. Added more gas drier and took it for a spirited drive in the country!! (IMG:style_emoticons/default/driving.gif)

Yeah Baby! (IMG:style_emoticons/default/aktion035.gif)

I think she's back!

...Glad you got it!..... (IMG:style_emoticons/default/shades.gif)
peace(fried pertronix leaves a bad taste in my mouth!LOL)