Megasquirt on my M110
 

Finally found the time to buckle down and get to work on the M110.

Attachment 94563

Decided on mounting the relay box on the right fenderwell. I didn't care for this spot because the exhaust is on this side. There isn't enough room on the firewall, mounting it in my preferred location (left front fenderwell) is counter productive due to the length of the controller cable required.
Attachment 94564

A better view without all the wiring mess in the way. Mounting it this close to the shock tower has it's drawbacks but the pluses out weigh them. The front two holes have to be drilled through a doubled metal area. A fact I discovered at the cost of an expensive drill bit. It has to mounted far enough forward to allow access to the DB37 connection with a screwdriver to tighten the locking screws. A fact which was discovered the hard way as once the cable is in place you can't access the rear hold down bolts to tighten them.:o This also worked out well on my '74 as it gave me easy access to the needed power. The sensors will also be on this side (coolant, O2 and intake temp) so it shortened up my wiring runs.
Attachment 94565

I would suggest BUYING the relay cable pre-made. Unless you are adept at fine wire soldering and have a solder pencil it is a real pain. You need to remove one of the DB37 housings to feed it through the hole in the firewall. The image is purposely fuzzy to not show my nasty-arsed soldering job.:P
Attachment 94566

Where the controller unit is located. It will be hidden by the under dash knee cover. When you mount it take care to leave enough room for cable access to BOTH ends of the unit. The DB37 will be attached on the side closest to the hole in the firewall and the DB9 tuning cable has to have enough room for easy connections. Oh yes, once again, the box needs to be mounted BEFORE you install the DB37 cable. Frick!
Attachment 94567

Rough mounted showing the cable running through the firewall. It was at THIS point I discovered the whole screwdriver/mounting problem.

Final mount of the relay box with some wires I attached for testing the unit's operation. Just a couple of sensor wires and tach input which will not be in the haphazard way they are now.

I picked up the power at the terminal strip already mounted on the firewall. Both 12V battery and 12V ignition which made my wiring run short and fairly neat. You can't see it in this picture but the ground for the board is routed to main engine ground strap.

Attachment 94568

It's alive! The reason for my sloppy sensor wiring. I wanted to get the electrical connections verified before I went further. Nothing like an overlooked connection problem to really frustrate you later on down the process. The injector pulse reading is in the red because there are no injectors installed for the ECU to get feed back.
Attachment 94569

The wiring is good and we have power so it's time to move on to the next phase. The TBI unit. I get to cheat because I just happen to have an M110 engine sitting on a cart in my work shop. Carb, linkage, most hoses and lines removed for ease of access and display purposes. You won't have to strip your car down this far.
Attachment 94570

The next two pics are of the Holley adapter plate (Holley part #17-41). I did have to re-cut the two rear mounting holes and using a dremel tool with a carbide bit recess a socket for the use of allen head cap screws to get the clearance I needed for the TBI. I'll show them in the next series of pictures.
Attachment 94571
Attachment 94572

I also drilled and helicoiled the three TBI mounting holes for metric threads. Not really needed but I figured I'd be consistent instead of using a mix of standard and metric bolts.

Time to begin fitting the TBI unit.

Used an old gasket to make the template for the adapter holes.
Attachment 94573

The next two are rough fitting the adapter. They are not the best of shots but you can see where I had to cut the recesses for the rear allen cap screws.
Attachment 94574
Attachment 94575

One thing which needs to be dealt with is the IAC on the GM TBI unit. It originally had a thick plastic "surround" into which the wiring plugs. That wasn't going to work as it hit the cam housing. Two ways to deal with it. Plug the hole and use a remote IAC or remove the surround and use some right angle connections. I went with the connectors. The surround is easy to remove as it is a brittle plastic. I gave it a quick buzz with a cutting wheel mounted in my dremel and it snapped right off.
Attachment 94576

Rough mounted showing the proximity of the IAC and the cam housing. It's not as close as it looks and once the connections are on there will be no interference.
Attachment 94577

Here's how you take care of that pesky IAC problem. The pins are hollow so a quick bit of soldering, some heat shrink, and we're in business.
Attachment 94590

Pre-wiring the TBI unit because it's a lot easier doing it on the bench than leaning over the car laying my forearm on that hot soldering iron I keep forgetting is right where I left it!:(
Attachment 94591

A view of how the IAC wiring looks when completed. Plenty of clearance!
Attachment 94592

A rough view of how the wiring will be run. It will be in a split loom and will run under the stock air cleaner. You'll only see it at the relay board connection. Neat, clean and out of the way.
Attachment 94593

The air horn which goes on top. Same size as the original Solex's air aperture so the stock cleaner slips right on it. I might have to shorten the riser just a tad. Probably the thickness of the adapter plate. It's hard to tell with the loose engine.
Attachment 94594

Nice work. I'm interested to see how the TBI setup works out. I would suggest building an aluminum heat shield between your relay board and exhaust manifold. Which version of MS are you using?

The old Holley carb set-up. Works fine but I want fuel injection with computer control and the ability to go to a complete managed system, fuel and ignition.
Attachment 94767

One of the few modifications I had to make to the actual original set up. I had to grind 1/4" off these two throttle bracket mounting holes. It would be easy to undo this if I wanted to go back to a carb for any reason. Just a couple of flat washers and this never happened. I had to grind these to allow the throttle bracket to sit below the surface of the adapter plate. I could probably have removed the needed amount from the plate but this was much easier.
Attachment 94768

Rough fitting the TBI unit with the first version of linkage installed. I did have to remove most of the ridiculously cumbersome throttle bracket plate on the TBI unit itself and elongate the mounting hole for the linkage. Dremel tool to the rescue! Those are some standard cable ends available at just about any auto parts store with a short bit of all-thread.
Attachment 94769

Another alteration I had to make to the original set up. I drilled two 3/16" holes in the original feed arm and riveted an upright bracket piece. I didn't hurt the structural integrity of the arm and in fact the pivot ball for the original carb linkage is still in place. Simply drill out the two rivets, remove the bracket and you're back to stock. A small bit of the TBI external bracing rib needs to be ground away to allow the original feed to go all the way forward. You could probably get away with just adjusting the actual "throw" of the accelerator linkage (small rod mounted by the firewall) but I had the TBI unit off and it was one less thing to be changed on the original.
Attachment 94770

TBI unit mounted and the first fuel line in place (supply). It was a little tricky but using a coat hanger as a template I got it figured out. The first bend coming from the TBI unit is tough to do. It needs to go up just a bit to give adequate clearance for the linkage. I'd suggest using a spring style of tubing bender for this first bend and then using a standard bender for the rest. I'll be re-working this line because I am not 100% thrilled with the way it looks. Works fine but I want it to look a bit better. It's not too bad. $14 for the line. Could be worse, we wont mention the $50 IAC I screwed up.:o
Attachment 94771

The return line formed and in place This is a lot more complicated than it really needs to be. You could actually just install a 2-3 inch stub and then attach a rubber line to it. There's no pressure on it. I went ahead and bent it all the way out because I was in the mood. There will be a bracket holding the lines to the intake. The return line is 5/16" and can use standard fuel line. The supply line is 3/8" and you should use fuel line clamps. There's not a lot of pressure (10-15 lbs.) used on TBI but better safe than sorry.
Attachment 94775

Oh THIS looks familiar! I went through this on my M115. Looks like a psychedelic spaghetti convention! Initial wiring just to check it out.
Attachment 94776

Here's the cause of a full wasted day. You wouldn't think BOTH of the injectors I pulled from a Pic 'N 'Pull yard off an 1987 GM product and let set around for over two years collecting dust and grime would be bad, now would you? Yup. They worked at first then quit. Spent a few hours troubleshooting my wiring, relay board and ECU before I realized they weren't "clicking" when I ran the MS in "injector test mode". Replaced them and all was well.
Attachment 94777

Here's the wiring cleaned up, bundled and routed in the firewall brackets. Just a little better don't you think? I left extra on the relay board end because I know I'll be re-routing it just because of one reason or the other.
Attachment 94778

The O2 wiring routed along the firewall. It runs under the heat shield back past the transmission. Since this is a 2 BBL TBI I needed to either install 2 O2's (one in each pipe) or install the O2 into where the pipes merged. I went with the single. Since it was so far back in the exhaust system I went with a 4 wire Bosch unit. This is a heated unit so it won't lose the temperature during idle or low cruise. A three wire (no return to the ECU, just a signal, heat power and heat ground) could be used with the same results. I used the 4 and ran a return to the ECU because I had some flaky problems with my M117 conversion regarding a consistent O2 signal and I figured I'd try to eliminate it. My M115 uses a single wire because it is a single injector TBI and it's mounted within 6 inches of the exhaust manifold so no need for a heated unit.
Attachment 94779

The fuel pump and filter mounting will be the same as I did on my M115 which is shown in the other thread. I haven't done them yet because of course, I just filled the tank up before I started this project and I'm going to wait until it's below a 1/4 of a tank to pull the lines.

I've been driving it around and I must say I'm impressed with the smoothness of the car. I've got a slight "stick" in the linkage coming off idle. Gotta smooth that out but otherwise it just zooms along. A lot more even power curve than the carb ever was and it was a darned good carb. Getting the tuning done now and learning a lot about the Tuner Studios software.

Next step, converting to a Ford EDIS wasted spark ignition. I should do it first on the M115 but I'll probably do it on the M110 since I have the loose engine sitting there which makes it a lot easier to fabricate parts.

MS-II, software version 2.889 and a version 3.0 home built board. Using Tuner Studio for the tuning.

Looks like a relatively painless installation. I've been using MS2 extra firmware with a lot of success. They've incorporated 16x16 ve tables and a lot of MS3 features into this firmware. Currently on V3.1.2. Good luck.

Yeah, there's a long, painful, complicated story I have regarding the MSII-Extra code. I'd truly love to have the 16X tables but it was a 2 week ordeal upgrading to the 2.905 or whichever version it is I actually have. It involves Linux, Tuner Studio, Easy-therm, Windows XP, 2000, Vista and MegaSquirt's "easy to update" firmware


Bring a barrel over and I'll give you the story.;)

I've had my fair share of gripes with MS2 extra mostly around the idle control setup. Fortunately enough people complained that somebody came up with a rival version of the firmware that resolved those issues. MSextra gets rid of easytherm all together. CLT calibration is a drop down menu with about a dozen examples already stored. I have a GM air temp sensor and MB CLT using VW L jet calibration.

fuel economy?

At the moment it's hard to gauge the economy. I was busy playing around with the tuning of the ECU when I did something stupid. I was concerned with the noisy tach signal I was getting from my Crane XR700 so I decided to convert over to spark control mode run by the MS controller.

Don't do it! The Crane opto receptor can not handle the straight +5V voltage put out by the ECU. It goes, "poof" and doesn't work any longer.:(

I've got a "Hot Spark" ignition unit, essentially a Pertronix system, ordered and hope to have it installed and back to running this weekend.

My initial impression is the mileage is considerably better than what I was getting with my Holley conversion carb. It might just be me being optimistic and I really haven't given it a good long test but I drove the snot out of it for a week and used only a quarter of a tank.

The set back gave me time to mount the fuel pump at the rear of the car where it belongs so something good came of it.

injector size
 

First off, thanks for documenting your conversion so well. I am planning to do the same thing and I have a couple of questions.
On the GM TBI unit I found 2 different sizes. One for a 2.8L engine and than one for the 4.0/5.7 Liter V8 engines. Which one did you choose? Since you are covering 2 of the wholes in the intake, do you feel the engine starving for air at high rpms?
What is the injector size/ part nr did you installed? What is the PWM value at idle, cruise and WTO? Do you feel that it is the right size?
And last question: Reliability Do you feel like this could be a daily driver? Thanks so much for you feedback

There are actually three different sizes. One for the 2.8L, one for the "performance engines" and one for everything else.

The 2.8L's one is rare. I would have used it if I could find one but I had to settle for the "everything else" one. The only difference is in the venturi size between the "performance" and regular one. One is 13/16" inch and the the other is 7/8". The one I used is the same as used on every GM engine from the 3.8L to the 7.0L so I know I have enough airflow, in fact I feel I have too much at idle but certain trade offs must be made.

I used the standard injectors for the TBI unit. I believe it is for a late '80's early '90s Chevrolet with the 3.8L. Those injector number all cross reference to the same replacement injector anyway. The GM dealer is the only one who pays any attention to different injectors.

The holes aren't "covered". Both the front and rear apertures open into the same chamber so the fuel mix is the same under engine demand.

I keep changing the PWM 'cause I am not smart enough to leave well enough alone.:o Of course, being able to tune on the fly is half the fun.

I am using it as my "daily driver" as well as the M115 and the M117's I've converted. The M115 (250C) is dead rock steady and has been for three years. The M117 ('85 W126) has been the "family sedan" for a year now and I drive the M110 (280C) every day, so, I'd say "yes" on the reliability factor.

I'll be posting some updated pictures on the latest on the M110 later today.

Okay, so I got tired of the stock Benz air cleaner and decided to do something about it. That danged thing is heavy! 22+ pounds, 10 kilos for you enlightened folks. That is a lot of weight to have whipping around on top of the engine on those chintzy little rubber mounts and the one stud on the TBI unit. So, even though I preferred the "stock" look it was time for it to go.

Spent some time brainstorming, searching on the web and general head scratching and came up with a solution.

I used a Spectre part # 9849 TBI "hat" for the cover over the TBI. Its main draw back was it is a 4" opening. No big deal, just used a 4"-3" coupling adapter. I ran the inlet (Vibrant Performance 3" 45 degree tube) down to an air filter housing I scrounged at the Pic'N'Pull. It's off a mid 90's GM product, Buick, Pontiac, Chevrolet, whatever they're all the same. The nice thing is it uses a standard filter available from any auto parts store for about $14. Much easier on the wallet than the $65 + stock M110 filter. Came out pretty slick but there is a big drawback. Now I can see all the wiring and linkage shortcuts which were hidden by the "flying saucer". Sigh, it's always something. I guess I'll spend tomorrow straightening out that mess and prettying up the undone things. Less than 10 lbs total AND more than half of the weight is mounted solid on the body. The TBI hood only weighs about 3 lbs and that is located directly on the TBI unit so no "flopping".

Pic #1. The nice SHINY, polished pieces. I HATE shiny!
Attachment 97624

Pic #2 Scuffed that nasty ol' shine right off the parts using some 100 grit.
Attachment 97625

Pic #3. A coat of primer, an undercoat of "hammer finish" black and a top coat of high temp semi-flat.
Attachment 97626

Pic #4. A side view of the piping. Now that I can see them, those plug wires look like an octopus missing a leg.
Attachment 97627

Pic #5. A top view showing the filter housing and all the wiring mess I get to straighten out. Believe it or not, the washer bottle still fits! I did lose the bracket with all the non-working relays and mystery wiring though. I'll probably install a brace running from the fender well up to the front wall. I seriously doubt it was for support but better safe than sorry.
Attachment 97628

In retrospect I would suggest using 3" aluminiumized exhaust pipe in place of the 45 degree piece I have. The angle is a bit more than 45 degrees, probably 60 degrees for a smoother fit. 3" is pretty standard exhaust size so any muffler shop would be able to bend you up a piece for probably $10-$20. Cheaper than the $29 I spent on the shiny piece which I cut 4" off each end and scuffed up.

So performance and fuel mileage? What are we seeing?

Jeez, Al, I just put the air system on today! Give me at least a week to get an idea.:D

I got upper 15's the last tank. I ran it up to ahem, a bit over the posted speed limit on the interstate with no problem. Let's just say, I went 20 miles in less than 15 minutes and it never missed a lick. That was with the stock air cleaner.

I've bonked the new system around town a bit and it SEEMS to be more responsive at 3/4's to full throttle but it might be just an impression. It is indeed a different sound. Not the "whoosh" I was getting with the after-market round air cleaner or the heavy "sigh" which seems to be the norm for the stock cleaner. It is more of a "deep breath" sound. Could just be resonance but I should imagine not being choked down to the 2" oval opening of the old cleaner has got to help, especially with the fuel injection.

Still not ready to go out and challenge those "ricers" yet but I'm feeling pretty cocky about mini-vans!:P

That must be pretty impressive

2012 Dodge Caravan Engine & Performance

Base engine size: 3.6 L
Cam type: Double overhead cam (DOHC)
Cylinders: V6
Valves: 24
Valve timing: Variable
Torque: 260 ft-lbs. @ 4400 rpm
Horsepower: 283 hp @ 6400 rpm
Turning circle: 39.1 ft.

Base engine type: flex-fuel (FFV)

Oh great, pop my bubble!

6400 RPMs? What engineering genius came up with that? I wonder how long it takes for those sleds to get to 6400 RPM's under load?

I'm not sure but it's supposed to do 0-60 in 7 seconds :). I love what you've done to that car. I really need to figure it how to install MS.

Dayumm! 0-60 in 7 seconds? Maybe I better lower my sights to UPS, Fed-ex and school buses! UPS trucks are the easiest to beat. They never go more than a block without stopping!:D

WHICH car are you looking to MS?

Quite a few actually.

My 6.3 and 71 280SL both have mechanical injection pumps which will probably cost considerable money to rebuild.

Then there are my Jaguar XJ12's. They use D-Jetronic, except it's made by Lucas. Yes.... Lucas made D-jetronic...it really doesn't get any better :).

Makes perfect sense. I mean, Lucas is known as "The prince of darkness". Consider it an upgrade. When the car catches on fire you have light to see the problem by!:D

Hah! I'm hi-jacking my own thread!

Oops... sorry... back on topic :)

Flash File
 

Mike D, i also have a M110 engine, could you post the flash file that you have already tweaked, this would be of great help for anyone williing to try this setup

Wow, found this thread while searching for WUR adjustment info. I have a 1985 280te that has an M110 and four speed (standard) from a Euro 280se (wish I had noticed the electric speedo)I would like to know what mileage you are getting. wonderful project. I am in Albuquerque.

Mike D, that would be the .MSQ file.

Ha ha ha ! That's funny.

Gerardo, I wish I could keep a single tune long enough to recommend settings. I have too much fun changing stuff around.

My basic tune was evolved from using the default settings with a couple of adjustments. Since then I've been playing with Tuner Studio's Analyzer settings. I'm having a bit of a struggle getting the O2 readings down at an idle. My cruise O2 is doing fine but I haven't figured out the problem with idle. I don't know whether it is the O2 sensor being so far back in the system (it's a heated narrow band sensor back where the pipes meet) or the fact the TBI unit is not allowing enough vacuum at idle (one of the curses of the hemispherical combustion chamber which is why MB added the auxiliary vacuum pump to begin with) to properly disperse the fuel.

I'm running 6 squirts simultaneous because it gives me a smoother idle. I tried alternating which brought the O2 down but gave me a lumpy idle and a definite decrease in mid-range power. The O2 isn't too bad, .8 volts but I'd like to get it down to at least the .6 range without it surging all over the place.

I'll post you up a file when I feel I have a good solid tune.

I located a VR distributor which I am going to install for spark control but in the middle of my researching I came across this:

International Mercedes-Benz Club Forum • Thema anzeigen - M110 Motor Discussion

Take a gander at about the 8th post down. Gets the wheels spinning in my head. The stumbling block to my going to the Ford EDIS system already has been the problem of the trigger wheel. The M110 has a humongous balancer on the crank which would require a 10 and 1/2" trigger wheel to clear it. Even having the trigger wheel is problematic because of the lack of clearance between the pulleys and the misc. attachments on the engine block. I had played with the idea he has done but I wasn't sure what it would do to the balance of the dampener.

I've got a spare M110 and after I get the spark going using the VR distributor I think I'll start working on the trigger/dampener idea.

I know one guy has converted his SL already but if you'll look at his set-up you'll notice he doesn't have A/C. If you have the A/C pulley it makes it much more difficult as the additional belt plus the added 2" gives you even less space to work with.

in my friends m104 3.2l we made something like this:
http://img687.imageshack.us/img687/4...f0091np.th.jpg

http://img295.imageshack.us/img295/5...cf0007b.th.jpg

http://img826.imageshack.us/img826/4...cf0008z.th.jpg

in my m104 3.0 24v i have the same thing... maybe You can make something similar to that :)

On the M110 the water pump is right on top of the balancer so I can't install a gear on the rear of the balancer larger than about 10.25" which is only 1/8" larger than the balancer itself. I don't think this will have teeth deep enough to trigger the sensor at higher r.p.m.s.

I'd have to have the balancer turned on a lathe to fit the wheel anyway.

Just brainstorming. I've still got to fit the VR distributor and go to spark control first.

Here's the pic, just to save you guys from having to scroll down through the other thread.

Attachment 103927

Mike D.:
At the end of Pg.2 (Dec. 2011) you were commenting on observed O2 sensor voltage. There are, I think, two factors that will stand in the way of leaning the overall mixture much more than you have already; an intake manifold that has runners of greatly varying length, and valve timing that features rather close lobe centers (105-107 deg.). The valve timing matter can be resolved by retarding the intake opening point and advancing the exhaust closing point to achieve a separation of 112-114 deg. (Offset cam keys are available from Mother Benz). The intake manifold, however, you are stuck with. It is the very problem of mixture varience caused by differences in runner length that brought us to port injection. Were you to lean the mixture to the point that cyls. 3&4 were running at .5-.6 V, the mixture at 1&6 would likely be dangerously lean. Although you are able to more closely control the mixture PREPARATION with TBI than with a carb, you can, unfortunately, do nothing about the DISTRIBUTION of the mixture, as that is a function of the manifold design

Yup, I'm already brainstorming the installation of port injectors on the car. I've got a spare M110 intake manifold just crying out for abuse. MSIII being able to control injectors sequentially is also giving me ideas.

Ideally I'd prefer to do the MS conversion on an injected M110 but we do what we can with what we've got. The steps are also a good learning tool for anyone considering doing the conversion and gives them an option on how far they can go.

I had figured the O2 sensor reading to be incomplete distribution. I dropped the Squirts to 3 per cycle and greatly improved the O2 readings.

It'll idle at 14.7 but you can feel it surge. I dropped the idle range to 13.4 and it smooths out. So I'm running it a tad rich at idle but the maps go back to controlled settings as soon as I get off idle (at about 950 RPM's).

The biggest change I've found is to not even mess with using VE Analyse Live but to just datalog the car, view the datalog, have the log analyzed and then either accept or reject the recommended changes. So much nicer to be either wrong or right as opposed to the constant switching of cells while driving. Datalogging also doesn't require the EGO correction to be on or off and it compensates for acceleration enrichment so you don't have to factor it in.

VE A. Live probably works fine with a wide band sensor set-up but I don't think the narrow band sensor I am using is giving it enough data soon enough for it to work.

17.8+ MPG on the last tank I ran through the car. 87 octane RUG on non-oxygenated fuel (from Oct. 1st to Apr. 1st all Az. fuels are "oxygenated" by mandate to cut down on winter emissions). In-town stop and go traffic, no A.C. use, electric cooling fan.

Not exactly a "mileage-master" but head and shoulders above the 13's I was getting on my various carburetor set-ups. I believe this is the peak I am going to see using the TBI and conventional ignition.

My next step is going to be using the Ford EDIS system for ignition control if other stuff will quit getting in the way. I don't see the ignition giving me much more gains in mileage but I might pick up some mid-range performance.

Let's see, about $700 invested in the fuel injection system, divided by $4 a gal of fuel, that's 175 gallons. So, if I'm saving 4 miles a gallon then I only need to drive a little under 10,000 miles to reap the savings. Piece of cake!

The real benefit is having a solid performance from my car and having the ability to upgrade the various components. Plus being able to tinker with the set-up. Can't get the gear-head out of the boy!:D

Not bad at all, good work!!!

If you get around to trying the individual injectors with crank-fire ignition working with MSIII's individual firing of injectors could get you even more. It'll be like a fancy new car's fuel injection system.

But, as-is, that's a good improvement. How's the driveability?

It's a completely different car from when it was carb'ed.

It has smooth response through-out the RPM range. The acceleration is a bit different than with the carb. as when you "punch it" you don't get the quick boost the acceleration pump gives you but you get a steady "pull" which is more efficient and actually gets you to speed faster. Mid-range response is immediate and starting is 2-3 turns maximum. I don't how it would be starting in cold weather and I don't intend to find out. I'll let you guys in the Northern climes have that weather test.

It does have an occasional "burp". It seems to happen when the car goes from "warm up enrichment" mode to standard. One quick "hiccup" and then it's done. I'm pretty sure it's just a setting change but so far it hasn't annoyed me enough to tweak it.

On your cold start cranking setting, set anything below ~40f to maximum pulse width. I think thats 25ms with high impedence injectors. Set cranking RPM to 250-350, no more. It'll start instantly at any temp no matter how cold.

Ummm, yeah, this is Tucson. ANYTHING below 40 F we panic!:eek: Now 40 C, that's a different story.:D

I'll give those settings a try. Starting is never a problem. The "hiccup" I get is when the ECU drops out of "WUE" or "ASE" into normal mode. It gives me a quick burp just at the threshold when it cycles enrichment on/off and then smooths out. No problem after this point. I'm guessing the settings are the cause because when I have the tuning software running this is when it occurs. As I say, it's not a problem which has been enough of an annoyance to really dig down and correct. It doesn't occur all the time, maybe once out of every 50 times on a "cold" start (where the car has sat for more than 3 hours but less than 8) so it's hard to track precisely.

A thousand times better than when I was dealing with the Solex.

Did you take down your page over at Megasquirt? The link no longer works.

No I didn't take it down. Its just not there anymore I guess. I have the same build outlined here.
My 93 2.3 quick and dirty Megasquirt conversion - 190 Revolution

And the M103 MS2 build
http://190rev.net/forums/showthread.php?t=38122&highlight=megasquirt

Heres another 110 conversion I found to be very informative.
280SL "K-Jet and Ignition conversion to Megasquirt" write up - Benzworld.org - Mercedes-Benz Discussion Forum

Well, the beast finally let me down. Been 3 and 1/2 years with no problem and out of the blue it began running like doo-doo.

Did the usual checks on it, fuel filter, line clamps, checked the strainer, etc.
Put a pressure gauge on it and found out it was operating at about 3.5 PSI. That ain't enough to make the mojo flow! Used a set of pliers to restrict the flow and the idle picked up to where it's supposed to be and the car runs as it formerly did.

Rebuilt the stock GM TBI regulator and still don't have enough pressure to operate the car properly. Hard to believe that a used, 25 year old part I pulled from a junkyard could be worn out.:rolleyes: I'm sure the seat inside the housing has worn away thanks to the wonderful ethanol blend we get here.

Ordered an adjustable in-line regulator to take the hokey stock unit's place. Just waiting on delivery for installation to get back on the road.

I also located a TBI unit from a S-10 with the 2.8L. Ordered that as well and will swap over from the 4.3L unit I have now. The only difference between the two is the 2.8L has 13/16'" venturi and the 4.3L has 7/8's. Same injectors, regulators, etc. No real reason to do it but curious as to what, if any, effect it might have on engine vacuum.

Don't know exactly what I did but it's fixed.

Installed the in-line regulator and had the exact same symptoms. WTF? Took a gander at the pressure tester gauge I have been using and noticed it was only showing 4PSI event though the inline gauge was showing 15PSI. Pulled apart the tester and found shreds of Teflon tape in the orifice. Wonder how long they've been in there and how did they get there? Somewhere down the line I must have had a leak and changed hoses. Either that or the lining on the hose broke down. Good possibility considering the oxygenated fuel we get here.

Back to the drawing board. Reworked ALL the grounds, connections and power feeds for the third time. Even pulled the relay board and touched up all the solder points. No dice, same problem.

Changed the Hot-Spark ignition for a Pertronix, made new plug wires (Pertronix specifically states NOT to use solid core wires), new spark plugs, new distributor cap and rotor. No difference.

Re-loaded the tuning settings but went to 100% map and disabled the EGO control. Runs like a top again. No sputter or miss. It's a little harder to start but I'm pretty sure it is in the After Start Enrichment settings which I had piddled with.

Beats the crap out of me what I did. For now I'm running it in open loop with the last known "good" settings. One of there days I'll hook it back up to the laptop and go through the settings to find out exactly where the problem is. I've driven for a couple of thousand miles since. I'm going to go with the mechanic's golden rule, "If it ain't broke, don't fix it".