loss of power when humid and raining

[hitmachine101]

97 M3

hey guys, got a issue here,
the car runs fine when simply driving, once you step on it though, she looses a great deal of power,

jumped on it getting on the highway and the check engine came on,

i read the code and it said cyc 1 misfired,

then 2 days later jumped on it again elsewhere and i had multiple cyc misfires, on 3 and 6 cyc this time ( this one was 3 codes )

each day it was POORING out, so im thinking bad coil packs but is there a way i can test them to see if there still good??

thanks guys

[hitmachine101]

ok just checked the plugs and the coil packs,, no obvious issues here,, the plugs look great, they have about 14K on them but none the less they look like the motors burning great

cleaned everything up and what not, took her out for a test drive and same issue, this time i couldnt get her to kick a code but none the less shes obviously loosing power,, ohhh the compression test shows 175-170 across the board so at least there consistent,,,, ohh and the weather is great out today,,, no moisture

i doubt its bad gas, it has been doing it on 2 seperate tanks of gas now.....

what do you think guys???

[hitmachine101]

ok so swapd all the coil packs with another M3 we have and i have the same issues, drives fine but if i floor it shes missing and loosing power

raining this morning and on my way to work jumped on the high way and she threw a check engine light again, Seems to throw it only when its moist out,, but the codes were misfire on cyc 4 5 and 6

my exhaust has been sounding funny of late, do i possibly have a hole and thats why my cars running like crap because of the lack of possible back pressure??

this is really frustrating,, oh i do have O2 simualtors for my post cat o2 sensors, could one have shorted out with the rain? and could be causing problems??? kinda figured if there was something wrong with that it would be giving me an O2 codes???

thanks guys

[Jeron]

I was about to suggest 02 sensors or MAF sensor when I refreshed my view and saw your most recent post. I would definitely start by checking the o2 simulators.

[hitmachine101]

ok ill check them to make sure the connection is good and theres no wires shorting or anything like that, i do have an extra New MAF, ill give that a shot to,

just put a new fuel filter in so that wasnt the problem

thinking maybe MAF, she goes just fine in 2nd and 3rd but she s unloading right into forth --

ill try those

[hitmachine101]

good call on the O2 simulator Jeron, went down there to look at it and for some reason or another, one of the wires leading from the wiring harness down to the female end that plugs into the O2 simulator or O2 sensor, one of these wires completely shorted out and melted its housing causing exposed the metal wire its self

thus explaining why the problem got worse with rain

im doubting the o2 simulator could produce this much juice to melt this wire

im just glad it didnt catch fire,

the only thing i can think of is that the alterator provided the power and a rock must have exposed the wire and then it grounded itself agains the frame

but i spliced a new wire in as far up as i could reach into the engine from underneath the car and am praying for the best, so far so good but i may be having myself a project this winter because these wires go into the harness right above the starter motor so guess im pulling the intake manifold if i have more issues

thanks again