Ice built up in AFM

[dnguyen1963]

Hi guys,

It has been very cold here the last few weeks. Yesterday (temp = 25F), I started the car and promptly got code 1215. I took out the box containing the AFM and found ice all over the inside. Cleaned that all out including the intake boot and the car is back to normal. For cold climate drivers, this cleaning should be included into your normal PM.

[chadthestampede]

It's regularly colder that that here and I've never had that problem. There's another issue here.

[dnguyen1963]

It's not chunk of ice...a whole bunch of small ice crystals preventing the flap from opening correctly.

[McGyver]

I'm not sure about m10s or m42s, but I know m20s have a TB heater to prevent this. The drop in pressure in as air passes through the TB makes the air colder and contributes to ice build up. The TB heater there the two coolant hoses attach to the TB so pass warm coolant. Unfortunately the gaskets leak after 20+ years, the screws strip, and so people bypass it.

If you live in a really cold place, I would make sure yours is working.

[dnguyen1963]

The car has been parked outside at 7F for two weeks with a lot of wind and snow so TB heater won't help this at all.

[101]

McGyver - just stating the obvious here, but the AFM is upstream of the throttle body so the TB heater won't help with ice crystals on the AFM.

Dnguyen1963 - are you running the stock air box and filter or something else? We had somewhat warm, humid weather in the Midwest and then the frigid cold so I can definitely see your issue happening, especially with a non-stock intake if that's the case. If you have the stock air box - I believe there may be a small drain hole in the bottom for accumulated moisture, but I'm not sure about that. There is on my Volvo. Might not be a bad idea to put a 1/8" hole in the bottom for that purpose.

Door locks are another issue when the temperatures change drastically. Today is the first day in 2 weeks that my E30 door locks were working somewhat normally. Can't wait for spring to return!

[dnguyen1963]

McGyver - just stating the obvious here, but the AFM is upstream of the throttle body so the TB heater won't help with ice crystals on the AFM.

Dnguyen1963 - are you running the stock air box and filter or something else? We had somewhat warm, humid weather in the Midwest and then the frigid cold so I can definitely see your issue happening, especially with a non-stock intake if that's the case. If you have the stock air box - I believe there may be a small drain hole in the bottom for accumulated moisture, but I'm not sure about that. There is on my Volvo. Might not be a bad idea to put a 1/8" hole in the bottom for that purpose.

Door locks are another issue when the temperatures change drastically. Today is the first day in 2 weeks that my E30 door locks were working somewhat normally. Can't wait for spring to return!

.
While I didn't have any part

I have a stock air box and there is a drain hole. I think that the howling wind and wet snow contributed to the formation of ice crystals. I have not seen it before, just this year.

[TobyB]

South Bend, IN

there's your problem...

t

[estoguy]

I live in Central Ontario in Canada, and the last three winters have been bitterly cold, and I DD my E30. Never had any issues.

[dnguyen1963]

I live in Central Ontario in Canada, and the last three winters have been bitterly cold, and I DD my E30. Never had any issues.

The Bentley actually describes this problem. Open up the AFM box and you might be surprise at what you find. For me, the ice was between the flap and the wall preventing it from opening. There were, maybe, twenty ice crystals and a small puddle of oil/ice in the intake boot.