M20 White smoke help

[520Ichester]

1988 520i M20.

Over the last week the car started to misfire, I thought it might be the spark plugs as I only do little trips of 3 miles a day. Within a couple of days the misfiring went from bad to worse. Now white smoke is leaving the exhaust, I think it is non-combusted fuel as it stinks of fuel and makes a popping sound when it get warm. The idle has also dropped down and when driving it requires a lot of peddle for any speed.

I replaced the spark plugs and tested to see if the HT lead needed replacing by removing one at a time and seeing if the problem go any worse, which it did not. At one point it seemed to sound better with one of the lead removed.

I am now guessing about the O2 sensor?. does any one have any ideas?

[Gene in NC]

Sounds like a head gasket. With engine hot and idling, hold a Kleenex across the taial pipe. If it gets wet and or shreds you're seeing steam. M20 head gaskets like to go, especially if engine has been treated to green antifreese and or long periods w/o timely change of coolant.

[632 Regal]

I concur

[dacoyote]

I concur

ditto

[632 Regal]

has the antifreeze level dropped?

[Blitzkrieg Bob]

for milky residue

[E34-520iSE]

I take it the white smoke (steam) is constant, rather than the usual cold morning steam that I get on a frosty UK morning. Are you having to top your coolant up? It should stay at the same level in the expansion tank for well...months really. Has the car overheated recently? The misfire could be down to a few things, a blown headgasket is just one of them. I can't comment on the O2 sensor as UK E34's with M20 engines don't have one fitted. The mixture is preset by the ECU.

HTH,

Shaun

[BMW5CARDVR]

Does Oil Look Like Chocolate Milk ??
Ifso Headgasket For Sure
Good Luck

[632 Regal]

I used to like chocolate milk but that stuff probably wouldnt taste so good.

Does Oil Look Like Chocolate Milk ??
Ifso Headgasket For Sure
Good Luck