E36 Misfire @ WOT & Redline

[iStagl]

Hello all,

As the title states, I have a misfire issue at WOT and redline. I'm setting this car up for autox, drifting, or track days, so let it be known these circumstances are usually while beating on the car (I need to be sure to not have a fault whilst making a lap!) Let it be known that I have done my research, searched every forum imaginable, read my Bentley bible basically cover to cover, and every wedophones wiring schematic I could find on this car, and I have still literally waited until I've exhausted all of my resources until I posted on here.

The car is pretty much stock, aside from a full cooling system rebuild (Stewart WP, lower temp tstat, mishimoto expansion tank, etc. It also has the UUC lightweight flywheel and a catless exhaust, with stock manifolds. I do have an exhaust leak on one exhaust bank at the collector from when we did the swap (Don't remember which bank right now).

Some background info: 1997 328is originally auto, now 5 speed. M52B28
Bought the car February of 2016 with a bad engine. Changed the engine and soon after changed the engine wiring harness due to the original harness being completely hacked by the previous owner. I also repaired much of the factory harness going from the fusebox to the front of the car, all the way to the passenger side, as my cooling fan wouldn't run after I did the mechanical fan delete mod. The car runs phenomenal at any RPM while the engine is cold, or not to full temp (I know that's horrible for it, but it was it was for the sake of testing.) Once the car "heat soaks" as I like say, it's starts breaking up at anything over 50% load, in any gear, once the engine has reached full operating temp and been there for some time. It also cuts fuel dead to cylinder 6 once I hit the redline hard, usually in second gear, or sometimes third. Put it this way, my shop is right on a main highway, and I usually cannot bang through the gears out of here without having a hard misfire by fourth gear.

Temperatures are fine, monitored religiously with my SnapOn Verus scanner. I originally was having overheat issues which made me realize my pusher fan was not working.

I had an E46 330ci that had a hard cyl#6 misfire with fuel cut, but that was due to low compression (by a LONG shot). So assuming the worst, I went ahead and did a compression test on this engine, and Cyl#1-5 proved 160psi with 6 being more like 150ish, but got to 160 after a few extra cranks. Cylinder leak down test proved 5% leak down across all 6 cylinders. Multiple smoke tests have been done to find ALL vacuum leaks and they have been repaired. The only thing I'm missing from my vacuum system is the charcoal canister which appears to be commonly deleted anyway. I have swapped coils, spark plugs (Which are all BRAND NEW from BMW dealer), and injectors around to try to make the misfire follow.

Food for thought:

The only thing that concerns me, is when I took the original engine out of the car it had the M50 manifold swapped onto it, (incorrectly, might I add, without the turner kit or anything to adapt the M52 style manifold connections to the M50 mani) but when I reinstalled the engine, I installed it with the stock M52 manifold that came on my new engine. I feel as though this may potentially cause restrictions if the DME had already been flashed to accommodate the M50 manifold.

Using the scope, I've found that I have a rattle when I blip the throttle from an idle, coming from the top end of cylinder 6. I scoped around the entire exhaust side of the engine and found the rattle was the loudest coming from 6. I pulled the cam cover to inspect any play in either of the 4 valves for that cylinder. I even prodded the tops of all four lifters on cylinder 6 as per the Bentley bible testing procedure, to no avail.

I need help brainstorming people, I'm at a loss!

It DOES have a couple codes stored in the DME that will not clear.
Mixture deviation
Camshaft position sensor
Multiple misfire
cylinder 6 misfire.

[Eric93se]

Cam sensor is an absolute must, be sure to buy an OEM brand.

Remove the cover for the injector rail to expose the wiring, tug on all the terminals to make sure they are grabbing well.

[Dec.e30]

Hi there!

I appear to be having a similar issue with my M52 e30 swap. WOT it judders and misfires but it clears as you get through the range. Misfires on cyl 2 +5. Don't want to jack your thread but this seems to be very similar to my issues and i'm curious to see if we can get a fix.

I have been advised by a BMW specialist that knock sensors can cause issues, i have replaced both of mine to no avail.

Does this fault only happen when the engine is warm?

[Eric93se]

Did you upgrade your fuel pump?

[Dec.e30]

Mine has been upgraded to the 325 pump. Ran fine in a 2.7 stroker...

[necodemus]

I had a misfire on mine on cylinder 6 when I rev it over 6200 rpm. Try almost everything and nothing worked. Finally got the budget to replace the origin muffler in June and the misfire is gone.