W126 EFI megasquirt - PeachParts Mercedes-Benz Forum

Das Benz · #1 01-15-2014, 09:47 PM

Slowly and steadily I've been contemplating on doing a EFI conversion on my 420sel.

Ive spend soo much time tinkering with the bosch ke-jet system on it, im starting to throw the towel in. Now don't get me wrong, when i got the car, it didn't run the best. But after doing a rebuild on the fuel distributor, replacing a few parts and fixing vacuum leaks. The car runs pretty darn good now. But its not as good as i want it to be.

there's a few hiccups here and there with the car, and some more tweaking. But i have kinda a similar problem that another folk had on here (lack of power at wot), and there wasn't a real outcome to the problem other then replacing the ecu, and things were back to normal. Although that's an easy fix for many in the south where the auto yards have many w126's to pick and choose from, up here, there's no luck. Don't get me wrong, the car drives perfectly fine, but if your trying to pass on the hwy, the car just doesn't have the get up and go that it should have. Even when comparing to my 560sel, taking engine size difference into account.

So with my constant desire to tune, improve, and increase performance with my other cars. I finally decided to do a full sequential EFI and ignition retrofit on my 420. Many might say its not worth it, but its not about resale value, or getting my money out of it. Its mainly "because i can", and "wouldn't it be bad-ass"

now before everyone thinks i lost my mind, there's a bit of future planning on my part. A large chunk of $$ for this project goes towards the MS3-pro module. Which, will allow me to run any future engine i can think off... LS7?...6.1hemi?... "MB 5.5 SC"

which are more then plentiful around these neck of the woods. A few other folks are working on a standalone TCU program for the 722.6 via a Megashift TCU module.

Having even a basic modern fuel injection (injector for each cylinder, and a wideband O2 sensor, you will be miles away from the KE-jet system. Its just soo much more precise compared to the KE's continuous injector fuel stream, which unfortunately results in poor emissions readings.

As far as time frame, the engine swap will probably be in a few years time, if at all with this car; but im not in a rush. First though, to convert the stock 4.2, i plan to dig in as soon as the weather turns nice, and i take the car off its winter road duty. If all goes well, i will definitely have my sights on doing this to my 560 as well.
Without a doubt i will get better MPG, throttle response, and a smoother engine.. Watch out

I will update this thread as time goes on. And when i score some parts.

To date far ive been busy snatching up parts to add to my arsenal.

New parts ive bought:
-PLX wideband O2 controller, sensor and gauge (with analogue output for megasquirt)
- 36-1 trigger wheel for M117/M116 engines (found this on ebay)
- Crank sensor bracket for M117/116 engine (same seller as the trigger wheel)
- GM 3Bar MAP sensor
- A few cam position sensors (different shape and sizes) Hall type
- A few crank position sensors, Hall type as well
- Knock Sensors (Subaru legacy ( sensors have different tune frequency for a iron block then a aluminum block)
- Tooling for bosch EV fuel injectors (for making your own fuel rail and injector pockets)

Need to get:
8x - Bosch EV12 fuel injectors (i have a list of cars to hit once i head to the auto wrecker)
8x - GM LS Truck ignition coils (built in igniter modules, needed for sequential ignition)
- Fuel rail aluminum blanks
- Fuel pressure regulator
- A nice sealed power distribution box, with relays
- Throttle position sensor (new online)
- AN fittings and hose
- GM Intake air temp sensor (scrap yard)
- GM Water temp sensor (scrap yard)
- Possibly a entire throttle body with stepper IAC incase i decide to not use the original Benz throttle, and expensive IAC valve.

Nuts, bolts, metal, sweat and tears.

Theres 2 ways you can measure engine parameters so the ECU can calculate engine load either via (MAP sensor + Throttle position sensor) or (MAF sensor- air flow). Having these set up properly allow you to get sweet MPG values. I cant wait to see what the 4.2 can do!

On the megasquirt forum, it looks like MAP+TPS seems to be more reliable for larger engines and less picky especially if you decide to run boost in the future

. MAF sensors seem to be best on specific engines they were designed for. Ie. engine swap with one already with a MAF sensor.

In the mean time, im just stocking up parts, doing wiring diagrams, and anxiously awaiting till the spring comes.

Theres been a few threads that touch slightly on the details of converting our older Benzes to EFI, but they lack ALOT of detail. This thread i hope to JAM-PACK! full of good info for others to snatch up and use on their rides.

Should be fun!

Mike D · #2 01-16-2014, 10:26 AM

I've been running my '85 500SEL for over three years using MSII (fuel only). I've been meaning to go to ignition control but have never felt the need or had the time to fuss about with it.

Going to EFI saved the car from the crusher as I was tired of dealing with the poorly maintained K-jet system the car originally had. The cost of a decent rebuilt fuel distributor, injectors, vacuum issues, IAC, etc. was three times the amount I spent on the MS system ($300 for ECU, $200 for various wiring, $30 for TPS, $300 for fuel rails, fittings and regulator, $20 for injectors and a few hours of "play time"). Emissions were cut in half and mileage was slightly increased. My cost could have decreased by about $300 if I knew then what I know now and didn't opt for the "easy way" on some items ($140 for a custom FPR, $160 for pre-made relay board and wiring harness, etc.).

http://www.peachparts.com/shopforum/search.php?searchid=6932161

Das Benz · #3 01-16-2014, 01:53 PM

Quote:

Originally Posted by Mike D

I've been running my '85 500SEL for over three years using MSII (fuel only). I've been meaning to go to ignition control but have never felt the need or had the time to fuss about with it.

Yea i was looking to go the MS3 way because it just opens up a few more doors for me if i want to go even more extreme with the whole build. Then i saw the MS3-pro... done

I really want to do Coil on Plug with my engine using LS coils, because i swear i have a timing problem thats causing the lack of performance when you really get your foot into it. Either the vacumm sensor in the EZL is having a fit or whatnot..
Ontop of that theres the benifit of doing sequential iginition on any V8 that used to have a single coil for all the plugs.. Dwell time limitiation at higher RPMs.

For those who dont fully get what im talking about. Dwell time is the time the coil needs to charge back up for the next spark. When you have 1 coil that needs to spark 4 times per rev (on a v8). When you get up to 5000rpm+ the coil doesnt have enough time to fully charge and give you a strong spark. So not only does your performance suffer, your coil is maxed out.
Having a coil on plug system. You technicaly have 1 coil for each spark plug, and it only needs to spark 1 time for every 2 revs. Dwell is no longer a problem at higher revs.

= Performance!

Plus the price of an EZL is scary. Heck, original bosch k-jet injectors are ridiculous up here.

Ive attached a good tidbit for folks to find EV6 or EV12 injectors. I made it up from info on the net.

tjts1 · #4 01-16-2014, 03:54 PM

I used 22# EV6 injectors in my M103 and 19# EV6 injectors in the M102. They were drop in, no adapter needed.

Das Benz · #5 01-17-2014, 03:09 PM

Quote:

Originally Posted by tjts1

I used 22# EV6 injectors in my M103 and 19# EV6 injectors in the M102. They were drop in, no adapter needed.

Yep, EV6 and EV12 injectors use the same bore size. EV14's are much larger.
They should pop right in on the M116/117.. In theroy. If not, the hammer has to come out

Ive read of folks using the EV6 with good sucess. I would like to try the EV12's because of the longer injector tip, im hoping it will more closely match the spray location of the original K-jet injectors, and potentialy not spary on the walls of the intake injector bore and atomize the fuel better.

tjts1 · #6 01-21-2014, 05:34 PM

The more fuel you put on the walls the better atomized it will be by the time it enter the cylinder. Remember that the intake valve is only open ~25% of the time and your injectur pulse can be up to 80% of the time no matter how you time it. Fuel that hits the intake port walls and the back side of the intake valve absorbs heat and vaporizes. Its a good thing.

duxthe1 · #7 01-21-2014, 09:18 PM

Megasquirt has an optional feature, X~tau modelling, where the fuel sticking to the walls and the fuel being sucked from the walls is accounted for during transients. Its not easy to dial in, and I don't routinely utilize this feature, but I was able to use it to get mine though emissions.

tjts1 · #8 01-22-2014, 02:44 AM

My 2.3 passed CA emissions 3 times so far on MS1 with very clean numbers. I tried to tune the wall setting settings in MS2, gave up after a short while. while some of the features in ms2 are brilliant, they're almost impossible to tune without hundreds of hours spent in a load cell

jadewombat · #9 01-25-2014, 10:53 PM

I would suggest switching to sequential fuel or crank trigger ignition, but not both at the same time if you go to MS. Just my advice though. It makes life a lot more difficult trying to tune both.

After having had dealt with Megajolt and Megasquirt, there's quite a learning curve. Dealing with MJ I re-mapped about 20 times until I was happy with the settings. Once you go crank-trigger, you probably won't ever want to deal with a distributor again. I felt the difference in low-end torque right away.

I dunno though, MS is a good system, but you get what you pay for. Their website is a complete joke. It's so old and outdated, you wind up going to forums when you have questions anyway. The whole website jumps around like one of those choose-your-own-adventure paperback books back in the early 80s. A lot of the information I found was wrong or outdated, maybe not in 2003 but whatever. Don't get me wrong though, best of luck with your conversion.

GGR · #10 02-03-2014, 08:19 AM

I did install Megasquirt on an early euro 5.0L engine. I considered going sequential but honestly power gains are really marginal. The slight improvement seems to be at lower rev mainly in terms of emissions. I ended up going EDIS wasted spark and batch injection (crossing the injectors - 2 on each bank). It works excellently and it's quite simpler to install and tune.

Das Benz · #11 02-07-2014, 08:10 PM

Quote:

Originally Posted by jadewombat

I dunno though, MS is a good system, but you get what you pay for. Their website is a complete joke. It's so old and outdated, you wind up going to forums when you have questions anyway. The whole website jumps around like one of those choose-your-own-adventure paperback books back in the early 80s. A lot of the information I found was wrong or outdated, maybe not in 2003 but whatever. Don't get me wrong though, best of luck with your conversion.

Yea I have to agree with the website. Its a tad out of date. But the MS1/2/3 are very DIY systems.

The MS3-PRO in my opinion is a mid level looking system. And a major improvement in the overall fit and finish of a standalone ECU unit t. I am actually anxious to get one fired up on the bench and test with it. If its not up to my standards, off to the next system.

Some new goodies showed up this week

hey_allen · #12 02-07-2014, 11:30 PM

DasBenz,
What is that in the first picture, on the far right?

I recognize the crank position sensor, bracket and tooth wheel, as well as the knock sensor, but what's the other bit? A linkage mounted throttle position sensor?

Das Benz · #13 02-07-2014, 11:59 PM

Quote:

Originally Posted by hey_allen

DasBenz,
What is that in the first picture, on the far right?

I recognize the crank position sensor, bracket and tooth wheel, as well as the knock sensor, but what's the other bit? A linkage mounted throttle position sensor?

The thing with the red and blue wire?
That's a new cam position/distributor sensor I found off ebay. Its for a Peugeot 505, it was only around 15$. It should work good for modding the distributor on the m116. I might be able to fit it in without doing any mods that cant be reversed. the bracket its attached to might not work, but its low enough profile that it could squeeze in there.

My goal for this build is to upgrade with the ability of being able to downgrade if I want to in the future. unfortunately I don't have a spare distributor housing that I could mod away on, so anything I do to it would be better if I could revert back to factory. That sensor is super low profile, it should fit inside the housing without drilling any clearance holes.

Das Benz · #14 02-22-2014, 01:29 PM

Finnaly had a Saturday off, and took a spin to the auto wrecker to see what part scores I could snatch up.

I was able to get a GM throttle body with IAC. I might not use it but it wasn't too expensive.

A set of LS truck coils.

And a whole slew of different injectors.

I got some EV6, some VW ones with some type of vacuum mist coupler on the end ill try and remove. And the ones I think im going to use.. SIEMENS DEKA 06C133551 injectors off of 2002-2005 audis.
Im looking up the flow rate for them. but a good rule of thumb is get similar injectors from cars that have the similar displacement for cyl.
These are for 3l v6 and 1.8l 4cly.. so that's about 0.5l/cly. so these fall into the range for a 4l v8.. But that's just rule of thumb..

for reality its based on many more variables. But as long as you don't run an injector too small or too large, you can tune it reliably.

Das Benz · #15 02-22-2014, 09:48 PM

Well after surfing the web for the rest of the day, I found almost no info on those Siemens Deka injectors. There was one thread on a german audi forum that mentioned something in the range of 22-25lb/hr flow .. but that's not accurate enough for me...SO plan B. Ive decided to build a injector flow bench. Its pretty straight forward, and I do industrial automation SO this should be no problemo.

Something like this is exactly what im building. Minus the electronic frequency generator. All I need to do is run a continuous 10sec pulse at 3bar to give me an amount that I can use to find out the cc/min - lb/hr.... Plus I can test to see if they match flow. AND.. I can use the bench to clean injectors too

.. plus it looks cool when the guys come by to hang out in the shop.
Fuel Injector Flow Bench | Software & Embedded electronics

I've already ordered all the tidbits today to make it

- Basic electric fuel pump
- A 2nd cheaper fuel pressure regulator (no need to have a fancy aeromotive for this bench tester, i just need a nice accurate fuel gauge)
-4x 250ml and 4x100ml graduated cylinders
- A industrial automation digital timer (precise down to 0.001 sec interval)
- Some relays and push button switches
- 12v 30amp power supply
- some leftover fuel rail from the bits I ordered for the car.
- A few AN fittings and some AN fuel line bits.

All I need to fabricate is a aluminum fuel tank with bulkhead fittings, and a surge tank after the fuel regulator to provide a consistent fuel pressure.

If anyone wants details for parts I can post them, but ill show them once they show up.