MS-II Configuration Questions

[sickwidit951]

Hey everyone, I recently installed a Megasquirt II on my 86' turbo and I have it working pretty well for fuel only at this point but I have a couple questions.

Firstly, I am using the stock coolant temp sensor from so I rewired it to MS (not connected to DME at all anymore). This works great except that I'm not sure what resistance values to use for calibration and I am concerned that the DME might need this sensor for its timing algorithm (seems to work alright though).

My only serious frustration is accel enrichment. It's working decently now after a lot of tweaking but theres a lot of room for improvement. What settings are other people using?

So far I am thrilled with this system and I can't wait for the router board to come out so I can do some fancy new ignition system and ditch the AFM! Any help on these issues would be greatly appreciated.

-Bob

[speedracing944]

I have the MS II built but it is for the V-8 swap. I will be running the Ford EDIS ignition system. I know ae1969 has a running MS II turbo 944 but I think he used the Ford EDIS ignition as well. You should contact him on this. I think he was the first person to run MS on a 944.

Speedy

[speedracing944]

can you put in a redundant temp sensor (GM) to run the MS and keep the stock one wired to the DME?

Why not run EDIS and do away with the old style ignition system as well. I think there would be great benifit to being able to control the ignition timing.

Speedy

[JustinL]

Hello,

I am running my car very similarly to you. For the coolant temp, you can do a pseudo calibration under the "calibrate thermistor" menu. If you know the ambient temperature at cold you have one data point and then you need another when the engine warms up to 83°C at the second tick on the dash.

Really, with our setups the coolant temp only determines when to shut off the warm-up enrichment. There are actual tables out there somewhere that you can use to acurately import to MS2.

For accel enrich, I'll have to check my tables. I found that the best way to get good throttle response is to tune the VE table first with everything else off and especially focus on the 80-100kpa range at really low RPM. I found the best way was to put it in 5th and open the throttle at low RPM to get the car into those zones and stay there long enough to get a stable AFR. Either adjust manually, or use that fantastic VE analyzer in the newer versions of megalog viewer.

X-tau is set to very minimally supplement regular accel enrichment. I'll have to get out my laptop later and get the accel timing values that I use.

Feel free to pm me.

Justin

[ae1969]

As Justin mentions calibrate the sensor. THere is a PDF with the bosch resistance table out there as well.

Definitely adjust the VE table first. The new analyzers are incredible.

Once you are there....... just park the car. And blip on the throttle. THe following will get your accel enrichment setup as close as possible and then you can fine tune it further on the road....

How I would tackle it...

FIRST make sure VE is as close as possible

Setting accel enrichment.

1. Set TPS threshold at 20 for now. (You can lower later) If you lower it too fast the car will hunt on idle and could even surge while driving. You should be able to get it down to 5.
2. Set decel fuel amount at 100%. You can lower this later.
3. Blip the throttle.
4. You will see the red bar. It will jump up. You will see the %/s change of the throttle. Try and blip as fast as possible. So that will be the MAX %/s change for the TPS. I make sure my upper value for %/s is below the quickest throttle response.....
5. I use the following for my settings.
75 8.0
40 7.5
20 5
5 3.5
BUT I don't use stock injectors. So the Value (ms) will probably be different for you.

The nice thing is you can make adjustments while you are parked and simulate the variety of throttle blips (quick/slow etc).....
YOU will feel the difference in throttle response. THe crisper and quicker the better.........
6. I also found that have accell enrichment set to full TPS (100%) at first...... You will get comfortable and start adjusting the map side once you get TPS nailed.
On my current setup I have 80%TPS and 20%MAP
Setting up the map side is similar to the TPS side..... but as you can imagine MAP and TPS respond in different manners.....

But in the end everyones setup is slightly different so you need to experiment.

Its a lot of work (but fun!) to dial the car in .....but my car runs 10x better than any 944 I have owned. Idles smooth. Throttle crisp and clean. It is truly amazing.

ANd with a half assed tune and conservative timing curve.... me and justin pulled 315rwhp...... without a hiccup.

[sickwidit951]

Thanks a bunch, that helps a lot. It looks like maybe I have the TPS %/s values set a too high and I was using high pulsewidths to compensate. I'll look into that VE analyzer too; so far I've only played with autotune a little bit. The table generator actually did a pretty good job. I just scalled the table and made a couple of tweaks and it's already handling AFRs better than stock.

Thanks Again,
Bob

[JustinL]

Here are my settings. I use 55lbhr injectors so you could scale to match. I use 100% tps with a pinch of X-tau.


154%/s 8.0ms
80%/s 6.0ms
40%/s 4.0ms
10%/s 2.5ms

Decel 75%
TPSdot thresh 10.0

Also set your lag factors as high as you can before you get too much noise. RPM, TPS and MAP are up in the 90s for me. The temp ones I leave low and that's about it.