Fuel leaking from muffler drain hole. Help me D: Updated!

[othatseric]

Ok so I recently finished up swapping out the vacuum and coolant lines under the intake manifold. Everything went back together smooth no problems.

The issue...
As soon as I turn the car on, fuel immediately begins dripping out of a small drain hole at the back of the muffler canister. (i'll post a picture and video next weekend).

Initial diagnoses & symptoms:
- The engine idles fairly okay, but stumbles every so often. Also smokes quite a bit.
-unplugged the afm and seems to idle a little better and doesn't stumble. However it does smoke a little more.
-the exhaust fumes smells very heavily of gas and a few drops of oil are coming out of the tail pipe.
-1215 code is being thrown via the stomp test at idle, but disappears when car is revved past 3500 rpm.

changes thus far:
-fuel filter
-spark plugs
-vacuum, coolant hoses
-DME reset maybe 3+ times.
-ICV, intake manifold and throttle body cleaned.

next steps:
-set of injectors (280150556)
-O2 sensor
-Blue coolant temp sensor
-Fuel pressure regulator
-AFM
-intake manifold gaskets (upper and lower)
-cleaning out all the electrical connections with contact cleaner, gonna get this stuff this week(http://www.canadiantire.ca/en/pdp/mo...1740p.html#srp)
-checking for sparking with tester

Things to note:
-I don't think it can be the AFM being bad because it was working fine when I first bought the car maybe 2 months ago. Also the idle and everything else was fine. Seemed to get progressively worse as I replaced old parts... lol

-Car revs through the range like nothing is wrong, but even more fuel drains from the muffler.

Also when the car is off, no fuel is leaking at all.

This problem is becoming more and more of a PITA  , I bought the car to enjoy and drive not fixing a 1 in a million problem UGH, I've been searching google like a maniac for the last 3 months with nothing remotely close even on other forums(bimmerforum, m42club, e30tech etc.) I need some help D:

UPDATE #1
Good News:
-electrical connectors were cleaned out
-car doesn't throw 1215 code anymore
-AFM ruled out

Bad News:
-#3 wire is super weak
-injectors harness (box that connects the injectors) was pinched to hell, & exposed bare wire

more to note:
-at cold start, NO fuel drips from the exhaust and idles perfect. As soon some throttle is given to move the car, idle starts to stumble and fuel starts to drip....

[DesktopDave]

I'm a a little confused...you have raw fuel dripping from the exhaust?!? You're sure it isn't water condensation mixed with unburned fuel, right? I'm not criticizing here, just trying to get a grip on the problem.

The 1215 code is an O2 sensor out of range, not a big deal. Revving past 3500 RPM is probably heating the sensor up enough to get the proper 0~1vdc output signal. The O2 reading is basically ignored until the car is warmed up, so this isn't a big deal right now.

Tell me more about the wiring box & harness. That's all pretty important stuff.

What kind of plugs did you use? I'd avoid the Bosch Platinums and use conventional NGK or Bosch plugs. I've had more than a few cars with running problems due to those Platinum plugs.

[othatseric]

I'm a a little confused...you have raw fuel dripping from the exhaust?!? You're sure it isn't water condensation mixed with unburned fuel, right? I'm not criticizing here, just trying to get a grip on the problem.

The 1215 code is an O2 sensor out of range, not a big deal. Revving past 3500 RPM is probably heating the sensor up enough to get the proper 0~1vdc output signal. The O2 reading is basically ignored until the car is warmed up, so this isn't a big deal right now.

Tell me more about the wiring box & harness. That's all pretty important stuff.

What kind of plugs did you use? I'd avoid the Bosch Platinums and use conventional NGK or Bosch plugs. I've had more than a few cars with running problems due to those Platinum plugs.

Ya, I double checked that it was actual fuel dribbling out of the muffler drain hole. Regarding the harness, initially I thought I had switched the coolant temp plugs, but I went back to double check for the single pin plug was in the sensor for the temp gauge and they were in right. Also the temp gauge itself wasn't pegged right off the bat. Like I mentioned, I also went back to clean out all the plugs that I touched with the cleaner I linked. The harness I found pinched had some exposed bare wire which I am hoping is the cause. At the moment, I have some refreshed 280 150 556 injectors ready to go, I want to get a new coolant temp sensor and I'm looking for a good condition injector harness bit. The harness part looks like:


As for the spark plugs, they were a brand new set of NGK BKR6EK 2288 plugs. When I pulled them, they were all carbon'd up pretty bad, electrode and porcelain. Dry though, no oil or any fluids on them. I was considering giving them a quick clean with some brake cleaner but I don't know yet.

[DesktopDave]

I'll keep an eye out for that harness. That can cause a lot of random trouble, especially if it's one of the crank sensor wires. Did you download the electrical troubleshooting manual? That will give you wire colors, so you'd have an idea what was damaged. Unfortunately the ETM is separated circuit by circuit, so you'd have a lot of pages to look at before you'll get an answer. The '91 318iS ETM is missing a few pages. I downloaded the '92 iC ETM instead, it's complete.

[othatseric]

I'll keep an eye out for that harness. That can cause a lot of random trouble, especially if it's one of the crank sensor wires. Did you download the electrical troubleshooting manual? That will give you wire colors, so you'd have an idea what was damaged. Unfortunately the ETM is separated circuit by circuit, so you'd have a lot of pages to look at before you'll get an answer. The '91 318iS ETM is missing a few pages. I downloaded the '92 iC ETM instead, it's complete.

I did, i saw your post on another thread like a month back about the 92' manual, thanks btw