'74 CIS: dashboard smoke and running rough

[Rick Brooklyn]

Today I drove my '74 Targa for only the second time in four months. It was also the first time I was driving it in the rain. The car fired up happily and felt nice and smooth. After maybe 10 minutes I started smelling something funny, and shortly after that smoke started coming up from the dashboard. I pulled over, keeping the engine running, and turned off the wipers, as I thought maybe it was the wipers motor smoking. The smoke ended almost immediately.

I drove another 5 miles or so to the shop where I had an appointment for an oil change. I mentioned the wipers / smoke to them, they said they checked the wiring of the wipers and everything looked ok.

When I drove off after the oil change (same oil as I already had on, Swepco 20-50), the car started running like shyte. It shakes at idle and when running at low RPMs, and feels kinda rough up to 3k RPM, a bit better between 3k and 4k, and almost normal over 4k.

It's a very "regular" shaking, if that makes sense - it's not like at idle it's hunting up and down, the idle is very stable, but the car shakes like it shouldn't be doing, and when accelerating from low RPM it doesn't rev up smoothly like it used to.

I've put about 90 miles in total on the car since it went rough, I filled up with about 7 gallons of fresh 93 Oct thinking that might help if maybe over the winter some of the gas had gone bad or something, but that didn't seem to make a difference.

Thoughts?

[timmy2]

Smoke could have been from oil in the heat exchangers.
You didn’t say if it smelled like an electrical fault (unmistakable) or oil burning.
The missing could be from your points assuming original engine.

[pmax]

Rick,
It could be something simple but always assume and guard against the worst.

Definitely don't run it if you hear unusual knocking noises.
If it happened right after the oil change, perhaps the "mechanic" mucked with your dizzy cap or plug wires.

[Rick Brooklyn]

Originally Posted by pmax

Rick,
It could be something simple but always assume and guard against the worst.

Definitely don't run it if you hear unusual knocking noises.
If it happened right after the oil change, perhaps the "mechanic" mucked with your dizzy cap or plug wires.

Thanks man. The oil change was at a top shop so I'd be surprised if there was a causal relationship.

The engine sound isn't bad or unusual, in fact, it's the shaking and vibration and laboring as it goes up in rpm. Any chance some of that might be an engine mount that's puking?

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[7783911]

Given its coming out of winter hibernation? Maybe you got a critter or critter nest somewhere...heck on my old TR6 I found Walnuts in places you couldn't imagine including the front tie rods

[Rick Brooklyn]

Trying a couple of videos to show sound and amount of vibrationhttp://cloud.tapatalk.com/s/5abe905e36728/VID_20180330_152939.mp4http://cloud.tapatalk.com/s/5abe90d566a6f/VID_20180330_152703.mp4

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[SalParadise]

They could be completely unrelated.

My feeling is that you need to be a man and pull out those gauges and get under there if it TRULY was smoke (and as someone mentioned WAS it electrical or oil in smell?)

If I smelled electrical, you bet your a$$ I would be all over the inside of that dash to check things out. These cars are very simple electrical wise, and the factory wiring was not exactly stellar (but not as bad as Lucas).

But they could be unrelated. CIS hates to sit. Even for four months.

[Rick Brooklyn]

Originally Posted by SalParadise

. CIS hates to sit. Even for four months.

Thanks Sal... Hates to sit as in might be worth driving it some more to see what happens, or as in needs some work?

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[pmax]

Dump in a bottle of Techron and see if it makes a difference.

And yes, time to be a man and crawl under the dash.

[Jack Stands]

I’d second the Techron suggestion. Unless you added a fuel stabilizer l8ke Sta-Bil, the gas may have gone bad already. If the smoke seemed electrical, remember that the instrument illumination lights as well as your glovebox lamp were not fused originally. Let the members know what you find.

[manbridge 74]

Sounds like it could also be an ignition miss. Some areas to look at would be points closing up. Spark plug wires in good shape, not leaking voltage? Condition of plugs. Air fuel ratio good? - when I was running CIS I could lightly wipe inside my tailpipe and only a little black would come off on rag.

I bet the smoke was oil.... electric smoke that’s visible is really acrid.

[Rick Brooklyn]

Originally Posted by Jack Stands

Unless you added a fuel stabilizer l8ke Sta-Bil, the gas may have gone bad already. If the smoke seemed electrical

Thanks. I didn't add stabil, unfortunately. If the gas has gone bad, what's my play? Try to burn it off anyway? or have it drained?

Originally Posted by manbridge 74

Condition of plugs. Air fuel ratio good? - when I was running CIS I could lightly wipe inside my tailpipe and only a little black would come off on rag.

Plugs were changed less than 10k miles ago I think. Ratio was perfect as of last fall, after they fixed a vacuum leak.

Is a points issue consistent with the engine running better at hi rpm than low?

[manbridge 74]

Usually more harder to start and slight miss at idle are signs. Wouldn’t hurt to take a look in there and eyeball it at about a business cards width when on tip of lobe.