Anyone know the difference between the Bosch CIS in the '90 CE DOHC 3.0 vs. the standard M103?

I plan to transplant my RENNTech SOHC 3.6 rom my wrecked 300E into it. I only know of the ICM is different...

Are the transmissions the same?

i would think that the calibration might be slightly better given the M104s inherently superior breathing. check part numbers.

Can the KE-Jetronic III be tweaked/tuned easily?

The 24V engine switched to Bosch KE-Jetronic 5 from the KE-Jetronic 3 of the 12V.

No, because it's electro mechanical and simplistically stated, it doesn't have sophisticated feedback from the engine.

True, but functionally the same.

M103 from 9/86 to 8/92 were KE 3.1, M104 from 9/89 to 8/92 were KE 5.2.
M103 Control unit # 0 0280 800 216 used until 8/87.
From 9/87 on control unit was # 0 280 800 256.

M104 used # 0 280 800 376 until 8/90, the from 9/90 on used # 0 280 800 422.

The KE 5.2 added a Knock Sensor.

Problem with the OP is that he is going to install a Renntech 3.6 which requires the Renntech control unit.

Are you referring to the ECU? I'll have to check it out, thanks.

Damn. I was hoping that the KE system can be tweaked easily to get some more performance.

Make sure that I understand what you're doing.

You have a Renntech SOHC 3.6, which is based on the M103?
If so it's either the performance package 1 with 225HP/234LB-FT torque or the package 2 with cam and ported/polished head with 255Hp/264Lb-Ft torque.

Your 300E that it came out of and was running at one time with no problems has a "EZL" unit which is the "pea-brain" of the M103 and a "KE Control" unit which manages the fuel system.

I would transfer whatever you had from the Renntech install as the KE Control unit was probably modified by Renntech to deliver more fuel to the injectors via the EHA.

MY comments are based on what it appears you are trying to do

That's the bad news....the good news is that the engine was fairly well "tuned" from the factory to give a wide torque band, good power, and not too shabby acceleration for it's time along with 20+ MPG.

No real electronics to fiddle with, which in a way is a good thing in an older vehicle

I hear that It works, and it does perform well. I have to keep reminding myself its not a boy-racer car...

It was a $53K + car when new.
Factor in inflation and it was a whole lot more then what a new E Class sells for now.

For a young guy, it's a great and classy boulevard cruiser................

3.6 liter renntech only pushing 225 hp? seems almost worth it just to get the 3.2l m104, which pushes 220, right? what did the renntech cost back in the day?

Last published price I have from Renntech for the M103 engines is $9950.00 for the Performance package 1 and $13900.00 for the performance package 2.
Price doesn't include installation.
That was as of last year.

Based on those prices I went with the twin turbo which ended up a bit less, but with greater power output.

Oddly enough even though the numbers are similar to the later 3.2L M104, I would put my money on the worked M103.
M103's even stock aren't that slow, very flat torque band that comes in earlier then the M104 variants

Woi. Expensive. Does renntech do a complete rebuild of the engine when it tunes? I assume they must right? So wouldnt that, theorhetically atelast, add years to your engine plus the added benefit of more performance?

Fortunately my wrecked car still runs with the 3.6L (Stage 2) so I can transfer whatever's necessary. I'll compare them more after I get the CE from the painter. The PO bought the engine from RENNTech and had a dealer local to him install it so I suspect it ran with stock "brain" and components. I may have to ask Bob about that. He quoted me about $15k earlier this year to build a motor if I really wanted one. He actually recommended finding a 500E instead.

From what I understand, they use a unique crankshaft. The rest is typical performance parts and engine building. I think they start with a 3.2 block since the oil filter is cartridge type. Since it's SOHC it must be a M103 head.