need some el help-o... fml

[spanishflea]

so here goes my woes...

m42 w/ 120k, misfiring at 2000-2500rpm. what gives?

some notes: changed oil to mobil1 10w-30 today. dropped some gumout in the almost empty fuel tank yesterday. k&n cone filter went in day before. could any of these be factors?

i've had this car for about a month or two now. fucking love it. it's been overall reliable - sloppy- but reliable. doing my best to get it up to snuff... but shit keeps getting in the way.


help!

[CorvallisBMW]

I'm going to go with spark plugs...

[spanishflea]

i pray you're right. just pulled em out and no1 had some oil on the threads, not the head tho, just the thread. the four of them all looked somewhat burnt.

should've tuned this thing the day i got it.

[spanishflea]

nope. did the plugs. wasn't it.

i'm starting to suspect valve troubles. seems even worse today. getting lawnmower effect.

[spanishflea]

i dont know, the more i think about it, i feel like putting gumout in my fuel loosened up a deposit that clogged my lines somewhere. plugs were dark n crispy when i pulled em this morning.

[Farbin Kaiber]

How old/original are the coils?

[spanishflea]

dont know age, but PO did coil/ plug conversion.

[s_ribs]

Plugs should be slightly brown. If they are more black than brown then you're too rich.

If that's the case, how is your temp sensor (front sensor on head) and O2 sensor? Those sensors control most of the dme inputs for air/fuel ratios. Temp sensor when cold, O2 sensor when at operating temp.

[spanishflea]

would that cause misfire tho?

thanks for the input, i'm lookin into it.

[s_ribs]

Sounds like you need: a) a bentley manual, an b) to do some basic google searches.

A misfire isn't just caused by inconsistent spark, it can be simply from incorrect a/f mixtures, etc. Pull out your multi-meter and test your sensors. You NEED to test what you can to get information. Don't even think about it more til you do!

Seriously- do some reading on generic engine info.

[3bvert]

fixed yor problem yet
when you get your miss, does it just miss or stumble/die at that rpm for just an instant
can you accelerate through that rpm slowly and not have the miss as passing through it, or only misses when held at a constant rpm
hows the idle first start in a few hours.
could be icv valve acting up , could also be throttle position sensor,

but as stated above, check your temp sensors, and while your at it, someplace on this forum, is the values for your cam and crank sensor

[spanishflea]

yeah i did a shitton of research to try and pinpoint it. pretty much too man diff possibilities since the misfire was inconsistent. by day 2 it was doing it from idle and all the way through. so i bitched out and took it to a shop.

dude was pretty smooth, i didnt think to test the coils w/ other cylinders. he found #2 had a surged wire. he soldered it, and that was that. i'm happy it was something so minor...

since it's already coil/ plug, i ordered a new set from bavauto, they're fairly cheap now from them/ probably not worth the money? wish it was never converted but whattayagonnado.