M102 CIS to EFI Questions. - PeachParts Mercedes-Benz Forum

Suped. · #1 12-10-2013, 12:53 PM

So the CIS on our 190 has been giving me **** since we bought the car. It's an old, worn out, and been poorly treated through it's life, as most K-jet systems are. I'm starting to think that EFI would be the best long-term CIS solution. I will also say that any stand alone system is beyond my budget, even Megasquirt.

I've been pondering a swap to Bosch LH 2.2 from a Volvo 240/740. The M102 and the Volvo B230 appear to be similar engines. Both are single cam, 2.3 liter 4 cylinders. The big difference seems to be with the compression ratio, the B230 being 9.8:1 and the M102 is something like ~9:1 (?). I'm pretty sure I could keep the Mercedes ignition, since the Volvo ignition and fuel systems are relatively divorced.

So there's one big question to start with: Is this a viable swap?

I know the big hurdles will be the wiring and the intake manifold. I'm more concerned at this point if this will work in theory, I can sort out all the practical stuff later. Is the compression ratio difference a big factor? Lh 2.2 is batch fire and not that advanced of a system, but I don't think there's much room for tweaking.

duxthe1 · #2 12-10-2013, 01:28 PM

One word.... Megasquirt.

tjts1 · #3 12-10-2013, 01:40 PM

LH2.2 might work pretty well. If I remember corectly from my Volvo days, 2.2 used MAF sensor and switch type TPS. LH2.4 and 3.1 had a 32 tooth flywheel sensor and POT type TPS. I don't remember how 2.2 gets its RPM signal, maybe off the ignition system. I think the bigger diff is not the compression ratio but the head design. The MB head is a hemispherical chamber while the Volvo B230 isn't. I considered this option but opted for Megasquirt. It was more expensive, complicated and time consuming to tune but worth it in the end.
190e 2.3 Megasquirt start - YouTube

Also even if you go the Volvo route, the Volvo fuel rail will not fit. You will need a saab 900 fuel rail for the correct injector spacing.

EDIT: If you have the parts and know how to make LH2.2 work, go for it. It should be easier to adapt than Megasquirt. Don't get hung up on batch fire vs sequential injection, you'll never be able to tell the diff. Most batch fired system fire the injectors twice by engine cycle anyway. I've run it up to 4 times per engine cycle for that super crisp throttle response.

Stretch · #4 12-10-2013, 01:42 PM

I hear you - MegaSquirt seems to be a lot of money to me too. There's got to be another way at the cost of programability and versatility.

All of these electronic systems seem to be capable of adjusting to changing situations - so my guess would be that compression ratio wouldn't make a big difference. I'd be more worried about the trigger points on a crank positioning system and which other sensors would be needed for a particular system to work.

EDIT - there you go look at post #3

Suped. · #5 12-10-2013, 02:10 PM

Quote:

Originally Posted by tjts1

LH2.2 might work pretty well. If I remember corectly from my Volvo days, 2.2 used MAF sensor and switch type TPS. LH2.4 and 3.1 had a 32 tooth flywheel sensor and POT type TPS. I don't remember how 2.2 gets its RPM signal, maybe off the ignition system. I think the bigger diff is not the compression ratio but the head design. The MB head is a hemispherical chamber while the Volvo B230 isn't. I considered this option but opted for Megasquirt. It was more expensive, complicated and time consuming to tune but worth it in the end.
190e 2.3 Megasquirt start - YouTube

Also even if you go the Volvo route, the Volvo fuel rail will not fit. You will need a saab 900 fuel rail for the correct injector spacing.

EDIT: If you have the parts and know how to make LH2.2 work, go for it. It should be easier to adapt than Megasquirt. Don't get hung up on batch fire vs sequential injection, you'll never be able to tell the diff. Most batch fired system fire the injectors twice by engine cycle anyway. I've run it up to 4 times per engine cycle for that super crisp throttle response.

I have less know-how than I wish I had. I really run out of know-how when it comes to computers, and Megasquirt is way over my head. I was more praising the primitive qualities of 2.2, I figured that an old batch fire system had enough wiggle room in it to be swap-able. I know that 2.2 can be made to use with the old Volvo 240 vacuum advance ignition systems, so integrating it into the M102 ignition shouldn't be a far stretch. I also chose 2.2 because I'd rather not get into things like modifying flywheels.

Is there anything to worry about with the difference in chamber design? I forgot about this.

Did you run the injectors into head, or did you modify/make an intake manifold? 2.2 has injectors on the manifold, I've never known if there was a clear reason to inject to the manifold rather than the port.

tjts1 · #6 12-10-2013, 02:37 PM

I ran the injectors into the existing CIS holes in the intake manifold. The way they're positioned, they fire right at the back of the intake valves. As far as installing the EFI injectors, its very straight forward. I recommend using more modern EV6 style injectors. These injectors fit right in without any modification.

Suped. · #7 12-10-2013, 03:11 PM

Hm. I never actually noticed the injectors ran into the manifold, I just assumed they ran to the head like a Volvo. Do you have a build thread on your EFI conversion? Where'd you source your FPR from? Looks like I'd need to make a threaded line if I wanted to run the Saab fuel rail to the Volvo FPR.

tjts1 · #8 12-10-2013, 03:34 PM

Here's the thread on my build.
190Rev.net - Discussion for Mercedes-Benz 190E W201 Performance, Parts, Tuning and more

Hindsight being 20/20, I used the wrong Saab fuel rail. There is another saab 900 fuel rail with a rectangular profile instead of the round one you see in the pic above. That fuel rail has a built in FPR which makes installation much more simple. My FPR is off an Isuzu. Eventually I'm going to swap out the round fuel rail for the square one. So far I have 50k miles on this setup.

For starters I would just start with the Volvo injectors until you get the car on the road, then upgrade to the EV6 injectors.

Suped. · #9 12-10-2013, 04:06 PM

Hm, that looks a lot newer. Is that off of a Late model GM-Saab 900?

Really though, I'm not worried about getting the right parts and making the hardware work. I'm worried about making all the wiring work. I've never swapped a fuel system like this, and I guess I'll have to start learning the basics. I only have a vague idea of how LH technically works. I'm not really sure where to start with planning out how to integrate the wiring harnesses.

porkface · #10 12-10-2013, 04:58 PM

get a wiring diagram for lh 2.2. there's a signal from the ignition to the fuel ecu off 1 wire behind the dist, when it's installed in a Volvo 4 cyl. it's used to calculate the load required in normal driving. good luck, chuck.

duxthe1 · #11 12-10-2013, 07:47 PM

Its hard for me to wrap my head around the idea of Megasquirt being expensive. If you already have a donor Volvo, then you'd have a leg up I guess. Still, I'd bet money that MS would be easier to install, even for a novice. MS is designed to be easily adaptable to just about anything and in a fuel only setup would be relatively simple to install. A big plus in the MS column is that there are forums full of helpful people that are eager to provide assistance.

The LH install would be pretty cool in a novel kind of way and would be quite an achievement. Aside from actually adapting it to work, the biggest downside I could see is the complete lack of tunability. You may find that the MB engine wants more accel enrichment, or less cold enrichment than the Volvo, for example. There's a lot of variables besides just displacement and you won't be able to account for any of them. You may get lucky and have it work perfect, but for the amount of work involved it would be disappointing to have to live with a collection of compromises if it doesn't.

Ok I'll quit plugging the MS, and good luck whichever way you go.

liquiddog · #12 12-10-2013, 08:12 PM

Looks like megasqirt is open source. How much better can you get than that. Power your car with an arduino!

tjts1 · #13 12-10-2013, 08:18 PM

Quote:

Originally Posted by Suped.

Hm, that looks a lot newer. Is that off of a Late model GM-Saab 900?

Really though, I'm not worried about getting the right parts and making the hardware work. I'm worried about making all the wiring work. I've never swapped a fuel system like this, and I guess I'll have to start learning the basics. I only have a vague idea of how LH technically works. I'm not really sure where to start with planning out how to integrate the wiring harnesses.

I'm not sure which kind of saab 900 it came off. I think it was late 80s or early 90s with longitudinal not sideways engine.

My only advice is no matter what EFI system you use, you should have a really solid understanding of how everything works before you start tearing into it. I've seen people get in way over their head very quickly with MSQ. Try to find someone that has already done a similar EFI swap to yours, the experience will be invaluable.

In the end, the most satisfying thing is starting the engine at -10c instantly without the huge stinking exhaust smell you normally get with KEjet.