EFI University

[El Verdugo]

I got a '90s Mercedes that has a turbo kit in it and also is fitted with a Megasquirt system. Aclient dropped it in and the mechanic at the shop asked me to see if I can fix the hunt of the idle since he managed to fix all the vacumm leaks that it had. So we think is a tuning issue now.

The system in question is a MS2357-C
I downloaded the MS3 software to see about connecting to it and no dice. I am totally new in this soft/hardware interface and wondered if any one can point me to the right software I need to download to try to connect to this black box.

Thanks in advance.

Alberto
_________________
Alberto I Correa, Jr.
EFI 101 Graduate 7-16-05
AEM EMS factory trained
www.corrperformance.com

[El Verdugo]

Got connection to this black box now, used TunerStudio to do so.

Sorry for the post, now just fighting this idle surge on this car. seems to be from a crappy alternator since the bat vol was low when the car is idleing and I see that it is using one of those small batteries to compound the problem.
_________________
Alberto I Correa, Jr.
EFI 101 Graduate 7-16-05
AEM EMS factory trained
www.corrperformance.com

[Matt Cramer]

We have some tips on how to get a good idle here:

http://www.diyautotune.com/tech_articles/megasquirt_idle_tuning.html

A lot of it is spark and fuel tuning, not tuning the "idle settings" per se.
_________________
Matt at DIY Autotune

[El Verdugo]

Thanks for the link and well said on the timing/fuel combo.
One thing that I do not like in the car at the moment is that mini battery and perhaps the Alternator is not working well. At idle I was looking at the BAT voltage and it was in the 11.4-11.6 Volt range. That is not good for the battery offset and proper voltage to the injectors at all.
_________________
Alberto I Correa, Jr.
EFI 101 Graduate 7-16-05
AEM EMS factory trained
www.corrperformance.com

[Matt Cramer]

I'd suspect the alternator at this point.
_________________
Matt at DIY Autotune

[Techsalvager]

Which firmware is the ms2 running? I believe newer firmware have better support for injectors and battery voltage that may help with idle and low voltage situations compared to older firmwares

[El Verdugo]

Let me check tomorrow when I return to the shop if I have to connect to the vehicle's black box to find out.

Also thanks for the suggestion
_________________
Alberto I Correa, Jr.
EFI 101 Graduate 7-16-05
AEM EMS factory trained
www.corrperformance.com

[El Verdugo]

Okay had a chance a for a few days to mess with this car and the symptoms that is having at the moment are the following.
On a cold morning start it will crank up and idle at 2500rpm for about a few seconds/until temp goes from 30 degrees to 140F.
As soon as it hits this temp or close to it, it will come off the fast idle and drop to 750rpm for a second and sometimes catching and leveling off to 1050rpms, but most of the time it will just stall and shit off.

I was looking at this thread for guidance, but to no avail.
http://efi101.com/forum/viewtopic.php?t=7561&highlight

Once the car is past this temp threshold it will crank up normally and then idle at the desired RPM.
So to say that the warm start is not a problem at the moment.

I have played around with the warm up enrichment, ASE values and still I have this cold start dilemma.

One other thing I did notice as well is that the ECT sensor maybe going south on me. On 2 occasions the from a cold start and after only 2 mins of the car idleing trying to reach a warm temp I would look over to the ECT temp on the tunerstudio and it would climb past 200F and keep climbing to 280F. I know this is wrong since I jumped out and checked the radiator temp and the radiator was still even cold and the temp gauge on the car's instrument panel was still at 60C.


_________________
Alberto I Correa, Jr.
EFI 101 Graduate 7-16-05
AEM EMS factory trained
www.corrperformance.com

[Matt Cramer]

You'll need to get the CLT sensor reading correctly to get a reliable cold start. Make sure it's calibrated for the sensor correctly and that the wiring is in good shape - you've probably got the infamous biodegradable wiring; it may be necessary to totally rewire it.
_________________
Matt at DIY Autotune

[El Verdugo]

Ok got this car on the dyno and did some steady state and then made some wot runs to the spring rate.






Well the thing I see is that this same box has a vacuum line going to the back of if to give it a load source. The question I am asking is does this back box have a built in map sensor like the Haltech units do? If so what is the BAR in it? At the moment I got to the sensor calibration section in the program for the map sensor and I see custom in there as the one that is being used. I am bringing this up since at the moment at only 6psi I am at 135% on the row of the TunerStudio and I only have 2 more rows to go up before I max out the load points in the map. So I need more resolution for the load points. I was to at least be able to map out 18psi on this engine.
_________________
Alberto I Correa, Jr.
EFI 101 Graduate 7-16-05
AEM EMS factory trained
www.corrperformance.com

[Matt Cramer]

Most MegaSquirts have a 2.5 bar MAP sensor - occasionally you'll find ones that go higher. 1 bar MAP sensor MegaSquirts exist but are extremely rare - there's probably less than a hundred in existence.
_________________
Matt at DIY Autotune

[El Verdugo]

[Matt Cramer]

It looks like you have the 2.5 bar already in there.
_________________
Matt at DIY Autotune

[El Verdugo]

[Techsalvager]

if its MS2 with MS2extra firmware you are stuck with 12x12 for your spark table.
But you can use table switching and switch via rpm or kpa or external switch to make a 20x12 or 12x20 map.
Also you can change the rpm and load values but not add or subtract rows.

[El Verdugo]