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TZ_280SEL 06-05-2016 03:17 PM

Modern EFI in the old Benz
Let me start by saying I think the D-JET system is great and was ahead of its time......but mine is 44 years old and has about 450k miles on it. I was struggling with very inconsistent running.....great when cold outside, poor when hot outside...horrible when it rained...but never the same two days in a row.

I decided to take the plunge and do a megasquirt conversion. I completed it this weekend (except for tuning) and am glad to say, it runs better with the default tune in it than it did on D-JET.

I decided to do the whole thing...I went with the Megasquirt MS3X DIY kit, installed a 36-1 wheel on the crank pulley, went with Chevy LS2 coils in wasted spark mode, used EV-6 19.3# injectors running semi-sequential, installed billet fuel rail from Ross, TPS from Bosch, and an IAC valve from an older jeep. Car started on the first try and idled like a champ.

Not cheap. I think when it is all done I will have spent about $1,243.03 to do the conversion, but it was my christmas/birthday present to myself. Probably way cheaper than sorting out my DJET.

If anyone is interested in more details, let me know.

TZ_280SEL 06-05-2016 04:23 PM

3 Attachment(s)
A few photos of the install

Mike D 06-05-2016 05:31 PM

3 Attachment(s)
My M115 build.

GM 2.5L TBI, MSII-E, 36-1 trigger wheel, IGN-4 coil from DIYAutotune wasted spark mode, standard GM temp sensors.

Initial install, all the wiring has been cleaned up and properly re-routed.

Attachment 1900073

Attachment 1900081

Attachment 1900089

Made the wires up before I finish mounted the coil. Not happy with the way they came out so I'm going to make a new set and get a cleaner, stock look

Scoot 06-05-2016 07:26 PM

Has anyone done this on an M180 engine?

Mike D 06-05-2016 07:57 PM

Scoot, I started engineering one for the M130 (same manifold I believe). I got stuck trying to match TBI's to supply both sides equally. Matching air flow characteristics to the torque requirements of the M130/M180 put a real crimp in the project. The closest I came was some single BBL TBI'S from an early Toyota.

Tried to source a manifold for the original injected system and went into cardiac arrest at the prices people were asking.

The guy bought 2 new Zeniths and the project got dropped.

A custom manifold would be the easiest and best solution.

alabbasi 06-06-2016 08:35 AM


Originally Posted by TZ_280SEL (Post 14473985)
Not cheap. I think when it is all done I will have spent about $1,243.03 to do the conversion, but it was my christmas/birthday present to myself. Probably way cheaper than sorting out my DJET.

Well done, you could probably sell your D-Jet suff and make most of that money back. I suspect that you're going to get much better fuel mileage with this setup.

Grubeguy 06-06-2016 02:13 PM

Fuel mileage alone would be an interesting reason to keep up with this thread. Keep the updates coming!

TZ_280SEL 06-08-2016 07:38 AM

Quick update. I finally got to spend about 10 minutes last night doing some basic tuning. The car now idles at a rock solid 900 RPM with an AFR of 15.0 (I'm using an Innovate wide band sensor). Was able to do some quick tuning at the higher loads/RPM and took the car out. It definitely has a very throaty note now when you accelerate and feels much stronger. Also smells better when idling.:smile

I must say that incorporating the Jeep 4.0 IAC valve was the best decision I made. I was able to build a small air box under it so I bring air from the throttle body to the idle valve and I return it to the engine using stock lines to the intake. I was also able to incorporate the crankcase vent to the air box so it works just like stock. The stepper motor allows you to dial in the idle EXACTLY where you want it.

On another note, I also pulled the entire dash to replace the non functioning heater blower. When I put it all back together, I took some time to seal the air ducts for the A/C system as they appeared to have some leaks. Well, it now blows as much on low as it used to blow on the highest blower setting. On high, it will actually blow your hair. I should have done this years ago.

I hope to get it tuned up over the next few weeks and then check mileage. I used to get about 14 in town and 17 on HWY.

Mike D 06-08-2016 07:59 AM

I'm interested in whether you see any mileage improvement using the ignition control. I MSII'ed my M117 (fuel only) and didn't really see much, if any, increase in MPG's. Power and drive-ability yes, mileage no.

Not really a good comparison on mine because the K-jet system I had was pretty trashed.

alabbasi 06-10-2016 12:14 PM

I just bought a W109 3.5 that I would really like to try this on. I'd be interested in seeing running results. Is this the same car with the Euro 4.5 engine?

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