Author Topic: Bucking in cold weather--fouled plugs? (Read 4018 times)

colin86325 · « **on:** January 22, 2013, 07:42:51 AM »

It was about 15 degrees this morning and the car started right up. I let it idle for about 8 minutes. When I drove away it was very jerky at low rpms. It would surge and buck in a way that suggested an electrical problem. I parked the car and the engine died.
I was able to start it up again and drove keeping the rpms above 3k; this seems to have cleared the problem.

I'm wondering whether anybody has an experience with these cars fouling the spark plugs idling during cold weather? The car has a stock ECU (not chipped). I ask because I have an E30 M3 as well and it is not advised to just let it idle during cold weather as you can foul the plugs.

keflaman · « **Reply #1 on:** January 23, 2013, 05:07:48 AM »

I haven't had that problem, but I usually don't let the car idle for more than the few minutes it takes to scrape off the frost. It's 11*F this morning so I might break my routine today.

Brrrrrr!

colin86325 · « **Reply #2 on:** January 23, 2013, 07:36:25 AM »

I know whatcha mean, keflaman! Another 15* morning here. This time I just started the car and drove off without any idling. The car performed without a hitch.

I think prolonged idling screwed me up. The park plugs are quite new (*though i can't remember the heat index), but maybe the idnition coils are tempermental.

I usually don't idle but I was trying to warm the car for my girl's kids.

DesktopDave · « **Reply #3 on:** January 23, 2013, 04:22:15 PM »

I had some trouble too. The car stalled when it was stone cold, but it's been running well since then. My battery is a little flat though, the load from the alternator might be a culprit.

Alternatively, I have a theory that condensed water settles in the tank and freezes, finding its way into the pump pickup screen or water filter, causing some rough running. Winter fuel mix is a bit more prone to water accumulation, and even though the E30's sealed fuel system is pretty good at minimizing water buildup...much of my vapor recovery system is original...near 30 years old.

Just wondering...is your car stock or have you performed the hose delete mod?

keflaman · « **Reply #4 on:** January 23, 2013, 07:07:52 PM »

Interesting theory. Just FYI, I installed a used, replacement tank last summer that I flushed, cleaned and completely dried out. Can't guarantee there isn't any water present, but there's not 23 years of crud caked to the bottom.

When the gauge was reading on "E" for the past couple of tanks, it was only taking 8-10 gallons to fill so I know the gauge is off. Curious as to whether or not my low level light works, I've been ignoring the needle and nervously watching for the dim glow; 338 miles on this tank thus far.

And a mouse in the glove compartment.

I have done the hose delete, COP kit and have a MarkD chip.

DesktopDave · « **Reply #5 on:** January 23, 2013, 07:33:31 PM »

You should be seeing that light any time now. Is the tank dented at all? Mine has a good sized dent I never took out - it will hold approx 11 gallons.

Mice are good luck. They never seem to infest newer BMWs.

colin86325 · « **Reply #6 on:** January 23, 2013, 07:59:40 PM »

I've gone over the car pretty well. I deleted the mess under the intake.

Funny, I was wonderign about ice in the tank as well. It looked pretty clean though, as I peeked in there when I had to replace the fuel pump the other day.

Geoff · « **Reply #7 on:** January 26, 2013, 07:34:45 AM »

my otherwise good running 91 does not seem to like it either when it dips below 20 F. It will buck a little and otherwise act up until it gets a little warm, then is ok. My engine would seem to be running on the cool side of normal, it reads normal on the guage but the heat only really kicks when you go down the road. if you sit in traffic for a few minutes, the heat definitely gets a few degrees cooler. This all occurs at really cold temps, and the car runs good otherwise. I have to agree with Dave about winter fuel, in fact I will go further and say this winter fuel we get just plain sucks. with all the water, additives and ethanol its a wonder the cars run at all
rant over
i feel better now
baby steps....

Geoff

colin86325 · « **Reply #8 on:** January 28, 2013, 02:43:02 PM »

Another cold day and the car starts right up, in less than .25 seconds--almost instantaneously with the key turning!

I haven't been letting it idle for prolonged periods, so I haven't had any repeat problems to report.

Geoff · « **Reply #9 on:** January 30, 2013, 06:05:49 AM »

yeah, I think they like to start and then drive slow till warm, instead of idle
Geoff

keflaman · « **Reply #10 on:** January 30, 2013, 05:21:37 PM »

I started using the garage for parking again. Haven't had any problems since.