PeteL

I get black smoke when WOT...what should i be looking for?
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Chunkerz

What kind of 944 do you have? Early? Late? Turbo? S? S2? 968? 924? 924S? 931? Something else I'm forgetting to list?

16valver

Black = fuel. You're runnin rich bud.

16valver

Also IIRC (someone may want to verify), WOT bypasses the O2 sensor and might even bypass one of the elements in the AFM (either temp or air volume [but I'm entirely unsure about that]). My initial guess, knowing nothing about your car, is that something is up with your fuel mapping. Could be an FPR getting funky as well. Check to see if there is fuel residue in the vac elbows coming off the damper and regulator.

PeteL

Thanks for the replies...the car is an 86 n/a.
I was told there were puffs of smoke when I accelerated during this weekend's 944 gathering in Orlando.
If it's running rich, how do I lean it out?

16valver

I don't think its necessarily a matter of leaning it out. More just figuring out why you are burning excess fuel at WOT. If you lean the car out you will effect the whole fuel map system. Less fuel = more air = more heat upon combustion. You probably don't want this all across the board. To determine if you are running rich all around, clock your gas mileage and see where you're at.

I'd check to see when the fuel pressure regulator was last changed.

I would also make sure the fuel quality switch is in "stock" position. To do this you must pull out the DME box, you'll see on one side of it that there is a little cap pressed into it. Pop the cap off and you will see a small *** in the hole that takes a triangular shaped screwdriver/tool. Get a golf tee and sand down the tip to fit the triangle. The *** needs to be turned all the way counter clockwise to achieve stock position. It doesn't take much effort to turn the *** so don't force it. If it doesn't want to rotate counter clockwise then its in stock position.

Next I'd look at your AFM to see if the cap is gone that covers the 5mm allen head adjustment screw. The screw controls a needle valve that acts as an air bypass. It has something to do with air fuel ratio adjustment. If the cover is still there I wouldn't mess with it. If the cover is gone its likely been tampered with and would probably be part of your issue.

At WOT most cars will smoke. If it isn't a LOT of smoke I wouldn't worry too much about it.

F40LM

How often do you run WOT? Are you sure it's not just blowing the carbon out? I must admit I rarely open mine up to WOT, bet if I did all kinds of carbon and maybe even a couple of small animals might get blown out as well.

black944 turbo

A little black smoke on wot is perfectly normal and fine. Cars are ment to go rich on wot. I would say this applies more on turbos than na but they both will do this. If fuel and oil consumption is normal I would not worry at all.

Fara

Mine blows a little bit of grey smoke near redline.
The black stuff is fine as long as there isn't massive amounts. The blue is less good.

My blue came from some very dead valve stem seals and some rather tired valve springs. Not sure if yours will be related to this.

Racerstev

Mine does the same and it's annoying as can be. Almost seems like
once the TPS clicks to WOT it goes rich. If I go to redline just off full
throttle I get no smoke, the downside is I also get less power.

Shouldn't the catalytic converter take care of this or is it getting overwhelmed? Just a note here, I kinda think my cat was gutted before I got the car. It smells like a old v8 with a 4 barrel most of the time.

Steve

PeteL

OK....from the sound of it, I am not going to worry too much. I don't hammer on the throttle all that often, so I think I am good to go.

mytrplseven

I'd read the plugs after a while of running "normal" to see if they indicate richness. Also, check the dme temp switch on front of engine (blue connector) to see if it's proper range or workiing at all. FPR and FPD could be an issue. Also, when you go to WOT, the TPS makes some contacts and if they're corroded, you'll get some weird info sent to the DME. Vacuum lines integrity?