The M104 block isn't much different from the M103 block so mechanical fitment is just nuts and bolts. Externally, it's little more than a 2.6 engine with a second cam. Internally, it has enough technology to pass a California smog test.

An M117 means hacking and welding. If you're up to it, go for an M119. As pawoSD suggests, if a gasser is a step back from Diesel, CIS is two steps back.

Sixto
87 300D

Carrying over the electronics needed for the M104 into the 190 would be the worst part of it all. Sounds like a nightmare.

Having experienced chronic rough idle on an M103, I look forward to wiring a 190E for HFM. Spreading the tunnel to fit a 722.6 might be more rewarding still :)

Sixto
87 300D

190D will always get better fuel economy, and give you an excuse to post in DD. 190E will be faster, and you can be cool like these guys (NSFW):

The Mighty 190 [Official Music Video] - YouTube

M102 8v with MS1 EFI is a completely different animal. It put my old 2.6 5spd to shame prior to its own MS2 conversion.
Not really. I did it for $350. I bet a V8 could be done for ~$500. MS1 and MS2 have been around long enough that theres plenty of well tested second hand systems for sale. 90% of the work is exactly what you're doing right now. Sitting in front of the computer and learning how it all works. If you have a basic understanding of how DC circuits work installation is a breeze. Road tuning the is fun part.

Hmmmm......so tempting.... :D I'd love to tune the o'l M116 to make 300hp... :D

City driving, I guess?
I was joking ;).

Answer
 

I suggest you look for the early 2.2 diesel.
Here is the basic math for you..

The 190D 2.2 five speed manual = 30 city - 52 MPG highway.

The 190E 2.3 (eight valve) five speed manual = 15 city - 26 MPG highway.

IMO: The W201 automatic transmission vehicles are at best "sluggish".

Parts are not an issue.

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1991 - 1993 model MPG

190D 2.6 automatic 17 City - 22 highway

190E 2.0 Automatic 16 City - 18 highway

190E 2.3 Automatic 18 City - 21 highway

190D 2.5 Automatic 29 City - 38 highway

190D 2.5 Turbo Automatic 26 City - 38 highway

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1991 300D 2.5 Turbo Automatic 29 City - 38 highway

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I don't know where that 52 number came from. EPA says 26/35 for the 190D 2.2 5spd
Fuel Economy of the 1984 Mercedes-Benz 190 D 2.2/190 E 2.3

And 18/26 for the 190e 2.3 5spd
Fuel Economy of the 1984 Mercedes-Benz 190 D 2.2/190 E 2.3

Real world supports both EPA results.
Mercedes-Benz 190D MPG Reports | Fuelly
Mercedes-Benz 190E MPG Reports | Fuelly

Answer
 

I own a 1984 190D 2.2 5spd, and that is what it gets driving from Detroit to Miami..

My professional experience places the highway MPG +/- 3 with working cruise control in overall good condition.

The EPA figures are useless for the 2.2 manual.....

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I've got a 2.2 auto and in mixed driving it averages 34-35 mpg. Worst I ever got on a tank was 33 mpg. Highway pushes up near 40 if you keep the speed down around 65 mph but drops off to 36-37 driving 70-75. I could easily see mid 40's with an OD 5th gear and 52 would be pretty amazing.

Chuckle
 

It is a Michigan rust car = best guess at least 200 pounds lighter.
FYI: That MPG is verified with GPS. :D

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I believe you...just saying 28 year old technology delivering mpg's in the same range as the new TDI diesels is pretty amazing.

As for your slugish statement, I only find that to be the case when the auto selects too high of a gear. In 1st gear its pretty quick off the line. The auto doesn't usually down shift at the optimum points when you've been cruising along and have to slow for some reason and then want to speed back up. The manual would be the better choice if he's shopping.

So whats the last year that they made that ? 1986 ?

Can you give me some more specs on that engine ?

That mileage sounds awesome !

One of these days I'm going to have to try this whole "65mph" thing... if the semi trucks don't run me off the road. I've heard great things about it.