This phenomenon has occured twice now, so I think it bears examining. I was drving to school this morning, which the choke still on. The car was nearly warmed up and I was drving rather gingerly: below 2.5k rpm. The car lost all power and would not rev above 1.5k. I pulled over and the car died. I tried to restart it, and it would only run for about five seconds, then it died again. After that, the car would not run. I got out and checked the carb. It was dark this morning, so I couldn't see that well, but it didn't look flooded. I waited a bit, and tried again. The car started fine and ran like usual. There was no sign of the problem. The same basic problem occured under the same circumstances about two weeks ago.

I guess I should note that the car in question is a '79. The car runs good other than these two incidents, but it backfires between upshifts, but not on downshift or decel.

Any thoughts?

Matt
1979 SA22C

 

A thought....In the winter, I usually have to push the choke in until the engine is idling around 1500rpms once I get it running. Otherwise, the engine won't accelerate very well. However, in the summer time, it will run fine with the choke all the way out all the time. As I said, just a thought.

 

This happened to me last week too. I was driving with the choke out and then it just died when I went to shift it into reverse in the parking lot after driving for about 10 minutes on a really cold morning. I find that when the choke goes back in on it's own, it's sometimes a bit early for these canadian winters, and the sudden drop in rpms causes the car to stall.

Last week when this happened it wouldn't restart right away and I had to push it into a parking spot at work, but two hours later when I went out to check on it it started up just fine. Since then, on cold mornings, I try to keep the rpms around 1500-2000, and slowly push the choke as I'm going along, so that when the choke pulls in itself, it's already idling under 1500 anyway, so there is no sudden drop causing the car to stall. Hope this helps.

 

Might be the start of a clogged fuel filter. Does it sputter at hwy speeds at all?

 

I was thinking fuel myself, but it seemed spark related, as when the car began to bog and die, it would pop and backfire like nuts, signifying to me that there was at least enough fuel, but it wasn't igniting. It doesn't see much in the way of highway speeds, but when it does, it's happy as a clam. Another thing, like I mentioned, when it's warm, it runs good, but pops between upshifts, but NOT on decel or downshift, which is back-asswards from the usual rotary exhaust popping. I can do mad downshifts and the exhaust doesn't make a peep, but heaven forbid I upshift at anywhere in the 2-4k region.

I just had a thought, which is surprising I know, does this have to do with the '79's design of not fireing the trailing plugs under certain conditions? That's one of the main reasons I want to do the electronic swap, so I can have all my plugs working full time.

Thanks for the responses. Keep 'em coming

Matt
1979 SA22C

 

The backfiring is pretty normal for cars that still have the thermal reactor. Mine did the same thing on upshifts.
The trailing plugs really don't have much to do with the power. I'd check out the fuel filter.

 

Vapor Lock?

 

Are you very high above sea level? If you are, then vapor lock may be an issue worth looking into.