Shooting Fire

[duleymane///iS]

So it has been brought to my attention from a fellow BMW owner (E90 335i) that my car has been shooting flames from the muffler. He said he saw them as he was following me on the off ramp from the Autobahn and as I downshifted from 4th to 3rd he said a foot long flame blew out. This is not the 1st occurrence I was drifting at a local Park and Ride and I bounced it off the limiter a few times in second and my buddies once again said it shot flames. Now it seems "cool" but I know something has to be up; it's a stock M42 with: Mess Under the Intake, New spark plugs, cleaned the ICV, running German 98 octane (91-93 American) stock manifold, 2.25 inch exhaust no cat with some German no name resonator and a Magnaflow muffler in the rear. Could it be a leaky injector? My fuel economy has gone down as well. ALOT I went from like 650km a tank to about 420km a tank. And my idle was preacher dick solid all winter at 850rpm, now it likes to mess around from 500 to 1300 rpm. Any input would much appreciated :D

[mtechnik]

Very inneresting..

[duleymane///iS]

Very inneresting..

Do you have any ideas? I mean the car still pulls nicely 5th seems a little less torquey though. Have you ever heard of a N/A stock M42 doing this? I feel like it could be a pre-courser to something bad :/ its very weird. I also forgot to mention and this happens quite a bit. I will be driving around base or something really slow like a village going maybe 30mph and when going from 2nd to 3rd or vice versa it after fires; not all the time but enough to get pulled over by the SP's I am pretty sure a flame is probably accompanied by those to as when people have seen the flames the after fires occurred if that makes sense.

[oldmann]

No Cat, still have O2 sensor? O2 sensor giving bad info to dme may have gone into failsafe mode. Will run rich to protect motor from running too lean.

[dannyyisntt]

Your car shoots flames because racecar

[Holland]

I'm thinking no cat may be suspect, although the O2 sensor is in front of it.

[bmwman91]

The M42 tends to run rich, especially when you snap off of the throttle it will still be dumping fuel in as the DME waits for the AFM to snap shut. Without the cat in there, it sounds like a recipe for flames.

[duleymane///iS]

No Cat, still have O2 sensor? O2 sensor giving bad info to dme may have gone into failsafe mode. Will run rich to protect motor from running too lean.

I literally have the o2 sensor there to just plug that bung up the wires are cut and everything and have been for over a year. Also I have some like blackish soot on my bumper where the DTM tips blow all this crud up there. And when I run on full throttle and let off I usually get big puffs of grey smoke from the rear. My Mustang/Drift buddy said its unburnt fuel being blown out. Does that sound right? When I changed my plugs a month ago they looked good too :???: Not too worried about it though still going to just proceed to drive the piss out of this thing. Seat time. Best investment on driving well.

[bmwman91]

Man, you just chopped off the O2 sensor wire? You should really fix that. You get awful mileage and lose power without the O2 sensor to give the DME proper feedback about the injection system. It would probably idle a lot better, too. Is the check engine light on constantly?

[Holland]

I literally have the o2 sensor there to just plug that bung up the wires are cut and everything and have been for over a year. Also I have some like blackish soot on my bumper where the DTM tips blow all this crud up there. And when I run on full throttle and let off I usually get big puffs of grey smoke from the rear. My Mustang/Drift buddy said its unburnt fuel being blown out. Does that sound right? When I changed my plugs a month ago they looked good too :???: Not too worried about it though still going to just proceed to drive the piss out of this thing. Seat time. Best investment on driving well.

Your problem, you found it.

Think about this. The race cars that shoot flames have aggressive camshafts and lack of exhaust restriction. Your car is running rich as is with minor exhaust restriction.

[duleymane///iS]

Man, you just chopped off the O2 sensor wire? You should really fix that. You get awful mileage and lose power without the O2 sensor to give the DME proper feedback about the injection system. It would probably idle a lot better, too. Is the check engine light on constantly?

Thats the thing its been like this for over a year and this just started happening. Its a Euro spec car doesnt have a check engine light.

[roguetoaster]

AFM sticking maybe? It's not chipped, is it?

[Dj Buttchug]

you need to get the o2 hooked back up. The issue here is no cat. Even a properly running car can shoot flames out the tailpipe if the exhaust is not restricted. if you are driving it somewhat hard and the exhaust is nice and hot from a pull and suddenly you let off or shift, a tiny bit of un burned fuel sails out the exhaust side. If the pipes are hot enough itll light that fuel as soon as theres enough o2 to get a burn (right at the tailpipe)

nbd. because racecar

[duleymane///iS]

It's not chipped I still hit limiter at 6200. I mean yeah Im not too worried about it just thought it wasnt good to have flames shooting out of a N/A not race car engine. I love not having to run cats. made my exhaust when it was built about 90 euros cheaper. the only problem is I constantly smell like exhaust and the cops when I pull on base say my car smells like a 2 stroke dirt bike haha. Tis a true statement

[Eric]

Sounds like the problem is behind the steering wheel.