Beginning to hate my MZ3

[cawb352]

Alright, first for the obvious, I really stuck my foot in it. I aquired a 1998 MZ3 with the S52 and a whole bunch of performance goodies already installed. It had receipts for over $10K in a professional rebuilt engine, but it would barely run. I figured it had to be something stupid but the previous owner was fed up. I bought it for way too much money and found out this guy was robbed severely by this so called shop. Now I need some help before I too have had enough.

I tore into the car checking plugs, coils, compression, fuel, air leaks and found no faults. So I decided to check the valve train. What I found amazed me. Several broken bolts, broken flange on the exhaust camshaft and cam timing was way off. I re-timed the cams, and replaced lots of bolts, installed a few helicoils, and changed the oil. It starts and runs smoothly at idle, from off idle to about 2K-2500 rpms, it is an absolute dog. It's missing and bucking and just generally running like crap. After 2500 it runs like a scalded dog. It's actually very impressive. then when you get back out of it, it has trouble catching itself and returning to idle and sometimes just straight dies. I've tried everything I can think of besides throwing massive amounts of parts at it and I just want to bounce it off some other people before I do.

Here's a list of the goodies:
Schrick cams
Lightweight internals
lightweight F1 Flywheel
M50 intake
Dinan cold air
Long tube headers with cats deleted
Full mandrel bent 3" exhaust
Larger MAF
Dinan Tune

NEW PARTS
VANOS UNIT
VANOS SOLENOID
SPARK PLUGS
FUEL FILTER
PLUS ALL THE STUFF THAT'S REQUIRED IN A STANDARD REBUILD

So if anyone has any insight into what is driving me crazy i would truly appreciate it.

[Farbin Kaiber]

This thread should be in the 24v subforum, you'll get more eyeballs on it that way that actually have some ideas.

Can you verify the tune is accurate for the modifications?

[golde30]

Yah that Dinan tune sounds sketch, unless this car was at dinan being tuned, which it probably wasn't since it didn't even run.

[jalopi]

If it's any consolation, Z3Ms are fucking sweet

[cawb352]

It's been built and tuned over 10 years ago, and it was running fine until about two years ago when the other shop tried to build it.

[Farbin Kaiber]

So, explain then what the other shop tried to 'build' if it was already 'built' and working properly. There is a whole lot of info we need here that MIGHT give a clue as to whats up.

[jalopi]

Probably building it from a stage 5 to a stage 5 and a half

[cawb352]

It slung the front balancer and took out a main bearing.

[cawb352]

It was running like its always ran, little hard to start in the am and tempermental when cold but absolutely amazing when it warms up. It was taken to Sebring for some runnning on the track and because the rev limiter is at 7900 when he missed a shift and went 4 to 3rd instead of 4 to 5th and over-revved it, it spun the balancer and it developed a lower end knock before the next lap. Then all this nightmare began when a rebuild was attempted by a supposedly qualified shop.