As in pull it from the exhaust pipe or unplug the sensor?
ohhh shit actually I’ve heard this very thing happening with those ebay mafs. that’s probably your issue. surprising it hasn’t thrown a code for it though…
I don’t know jack shit about bmw stuff but if this was any other car I’d say a MAF issue.
I got a known good MAF, needless to say, this is not the issue. I ran a compression test on the vehicle. Here’s the numbers:
CYL # 1 - 200psi
CYL # 2 - 195
CYL # 3 - 190
CYL # 4 - 165
CYL # 5 - 200
CYL # 6 - 205
My Bentley manual states that the minimum 142-156psi, so I have no clue whats going on here. The head was replaced, prior to me getting this car. I have no clue what vehicle it came off of. It also appears that it was never run trough a machine shop prior to the install. I’m seriously thinking about swapping out this engine for a 328 right about now. I’m going to pull the front O2 sensor and take it for a ride when the weather clears up. Hopefully this will tell me if it’s a clogged cat or not.
uhhhh something in cyl 4 is no bueno is you’re confident in that tests results
the bentley’s minimum is for comp across the board, not at one cylinder
sounds like a headache, but I can’t imagine why that would be limiting the motor from going above 4k
Head was likely surfaced a bit towards the limit which raises the CR. Those numbers are high but won’t cause this problem, not even with the one bore at 165psi. Those numbers would actually make this thing snotty as fuck. Usually when one bore is that low during a CR/LD test I’ll check it three times to be certain it’s not the gauge o ring leaking at the plug. If all come out that high it could be your gauge calibration is off a bit, or aformentioned head deck height change, without getting into major engine parts changing
Yes, pull the upstream 02 sensor right out of the bung and go run the car. Unplug the sensor from the harness so it’s not just dangling in mid air collecting debris.
Or just drop the entire exhuast off the car and run it. It’s going to be loud one way or the other.
Thanks again Adam, your always a help with my car problems. Now I just have to wait for this snow to go away so I can go drive it.
That’s what I was going to say! I’d love to bump my m42 to compression numbers like that. 
I’d definitely do a few compression tests though - as others have suggested - those high numbers sound oddly very high; the one 165 sounds just too far off the others to say the anything’s definitively bad without checking it multiple times.
Out of curiosity did you do the compression test while the motor was cold or hot?
Could one of the cams be timed off by 1 tooth? I have no idea how sensitive the pcm is to such things but i have seen it happen on other makes.
Vanos timing is kinda tricky on these motors
Yeah cam timing is very finiky on these motors as stated. One tooth off and the DME would throw a CAS code. But if the exhaust cam gear bolts were not tightened in the proper procedure it could be off by as much as 3/4ooth worth of chain and may not trip a code. Hard to explain without showing pics for reference.
Only one way to find out.
CJ just needs to stop buying BMW’s. IIRC you had issues like this with a past M3 correct :lol
used bmw with issues no way. that should be obvious
fixed, as usual
god you are an idiot (pitman obviously)
fuck you benny,
oppps :shift 
LOL…I know, but I couldn’t pass up this one. I like the E36 as much as I like the Porsche 944’s. I ended up getting it for 2K, because of the issue at hand. He was asking $3500. On a positive note, I learned my lesson form the M3, so I didn’t go chasing mystery codes and buying random sensors, for a few hundred bucks a pop. Right now, as it sits, I’ve only dumped roughly $200 into it, mostly preventive maintenance, plug boots, plugs, fuel filter, new hoses, ect… I did replace the cheap Ebay MAF, form one I picked up from Joe in Schenectady.
As of now I have properly diagnosed the issue with the help form everyone here. The cat is clogged. I pulled the front O2 sensor, and other than sounding like a tractor, it ran great. I have an appointment tomorrow to get it taken care of. Thanks for everyone’s help.
Well then you can thank Will for bringing that suggestion up and buy him a beer now 
Damn my bad, this would be the first time I’ve heard of that happening on an E36.