MS3 with MS3x

[87shelbycharger]

I've got a Dodge Neon 2.4L NGC engine in my 87 Shelby Charger and I've installed the MS3 with MS3x unit running full sequential. I've got low impedance injectors with the proper resistors inline and I'm using Chrysler 2.7L coil on plugs with a circuit built that is similar to the quad-spark. I was able to start the car a few times just testing to make sure that it would actually start before I cleaned up the wiring in the engine bay. It started so I was happy and carried on with the wiring install/cleanup. So the first part of this post was from a previous post of mine, but last night I was trying to get the car to start more reliably and more quickly. Doing more research I found that according to DIY Autotune I had to actually change my ignition capture from falling edge to rising edge. With falling edge i was able to start the car about 75% of the time, it just took longer than I wanted. So i changed to rising edge thinking, ok maybe this will fix it since this is the way the car/ecu is meant to run anyway. No such luck, when on rising edge the car would just crank and crank and crank, never even trying to start or even sputter. I've attached a few logs, both from when I had the ecu set to rising edge and falling edge, and also regular data logs as well as composite logger data logs. The MSQ is also attached incase theres anything that jumps out that I may have just blatantly missed.

Thanks for any help you can provide.

2015-04-02_00.33.44 FallingEdge.msl

2015-04-02_00.33.44 RisingEdge.msl

Current Tune 2015-04-02_07.11.26.msq

[87shelbycharger]

Here are more data traces, I couldnt upload them in the first post:

2015-04-02_00.33.44 FallingEdgecrankingonly.msl

2015-04-02_00.35.57FallingEdge.csv

2015-04-02_00.35.57RisingEdge.csv

And here is the link i used to help get the initial settings
http://www.diyautotune.com/tech_article ... n_420a.htm
Again, Thanks in advance!

[Matt Cramer]

If it gets RPM on Falling Edge, use that setting. Then make sure your timing is right.

[87shelbycharger]

Hi guys,

As an update, I seem to have gotten the car to start and idle on quite a consistent basis and tuning seems to be going pretty well. I've run into an issue where the idle is sometimes high, and other times low. I got the idle setup so it was rock solid and I was idling for about 15 min (tuning the tables little by little the whole time) and she was running and starting well that day. The next day I tried starting the car I had to change the IAC valve steps quite a bit, from 205 (mostly closed) to 150 (only about halfway closed) in order for the car to even start. Can anyone provide any input of where to start looking for problems? I'm not sure if this is something that is physically wrong with my setup, where to start looking if it is, or if its something glitchy with the software/tune. I've got a brand new jeep 4.0L IAC Valve in there and I've done the check such that 5 steps fully extends the solenoid (closing the idle opening) and 255 steps is a fully retracted (open) valve. The valve has been tested and appears to work properly. Has anyone seen any problems like this before?

Any help would be great.

Pat

[Matt Cramer]

[87shelbycharger]

StartsWell_1_2015-04-20_20.06.34.msl

Startswell_2_2015-04-20_20.37.20.msl

2015-04-20_21.09.13.msq

[87shelbycharger]

As you can see in the first trace, the Idle valve steps are 130 and the idle is around 650 rpm. Half an hour later I started the car with the same settings, and it idled up to 2200 rpm. I adjusted the idle valve steps up to ~180 steps just to get the idle back down to ~700 rpm. Has anyone seen anything similar and can provide suggestions of what may be wrong?

[Matt Cramer]

Try increasing the Time Step Size to 6 and the minimum number of steps to move to 3. This can help with a sticking stepper.

[87shelbycharger]

Thanks, I'll try that. I tried adjusting the "Steps while cranking" last night so that the steps while cranking is more open, lower value, than that of the standard "IAC steps" table. This seemed to help a bit as well, I guess it could be due to the fact that the engine sees more air to help start the engine, then reduces back down to stabilize the idle. Does this seem to make sense?

[jsmcortina]

Thanks, I'll try that. I tried adjusting the "Steps while cranking" last night so that the steps while cranking is more open, lower value,

That sounds backwards. A lower number is supposed to mean less air.

James

[87shelbycharger]

Thanks, I'll try that. I tried adjusting the "Steps while cranking" last night so that the steps while cranking is more open, lower value,

That sounds backwards. A lower number is supposed to mean less air.

James

I guess I'm not sure which way is "correct" but It works, and its how I've seen other msq settings as well.

According to the table about halfway down on this page, the higher the number the lower the idle and the more closed the valve is.

http://www.megamanual.com/ms2/IAC.htm

[87shelbycharger]

Thanks, I'll try that. I tried adjusting the "Steps while cranking" last night so that the steps while cranking is more open, lower value,

That sounds backwards. A lower number is supposed to mean less air.

James

Maybe you're thinking of PWM idle control valves?



found on the page http://www.diyautotune.com/tech_article ... uning.html

[racingmini_mtl]

James is right and you are referring to the wrong manual. Do not use the megamanual for MS3 (or MS2/Extra) since it has no information at all on MS3 and some information can be misleading or even wrong as is the case here. The correct manuals are linked at the top of the page.

Jean

[87shelbycharger]

My "start value" was set at 160, as I understand now, this needs to be set at the same value or greater than the overall number steps that from fully open to fully closed to work properly. The iac valve moves about 255 steps (full open to full close), should setting the "start value" to 255 help reliably start at the same idle rpm?

[Matt Cramer]

Yes. You need to be able to get the valve to close correctly from ANY position it may be in when the car is shut off.

[87shelbycharger]

Yes. You need to be able to get the valve to close correctly from ANY position it may be in when the car is shut off.

That may explain alot of things. I changed that yesterday after work, got the car idling at about 750-800 rpm, let the car sit for a few hours and then drove it again with a cold engine (it was 43 degrees in MI yesterday) and once it was warmed up it idled at just about the same rpm. Thanks for the help guys.