Megasquirt ems

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I'm wiring my megasquirt in the car now. I'll post a how to when I'm done.

Redtruck- are you still needing your factory computer to work for everything else? That's going to be difficult. Is there a reason you want to do a megasquirt vs using your factory computer? I'm guessing your build is pretty radical?
 
Uhcoog1 said:
I'm wiring my megasquirt in the car now. I'll post a how to when I'm done.

Redtruck- are you still needing your factory computer to work for everything else? That's going to be difficult. Is there a reason you want to do a megasquirt vs using your factory computer? I'm guessing your build is pretty radical?
Click to expand...

No, Redtruck isn't radical but she's a 03 model and I have fought with tuning ever since I first bought her new. I'm currently using a Crazy Spartan (lsa 112) with the basic add-on's. SCT doesn't support the 03 model hemi, Diable has issues with 03's and throws ABS codes and can lock the PCM so updates and other turners won't work, This requires dealership resets for the ABS problem and replacing the PCM for using other tuners. Plus Diablo/CMR tunes can't adjust idle, rpm/speed limiters. I've come up with a High idle mod to raise the idle but it really isn't adjustable and runs 800 cold and 650 warm.. Red is a street truck but I want total tuning control to give me the freedom of bigger cam and generally better overall tuning than my current SuperChip /PSC1-003 piggyback setup. Megasquirt looks very do able. But all of the trucks lights, AC, dash and accessories are run by the PCM. I would like to keep the original cruise which require the FBW to remain functional. So I'm going to try running the MS controlling only fuel, ignition and knock sensors. If that fails I'll go to cable throttle body and fab a new cruise control setup. MS recommends what they call a parallel install. Which is what I'll do.
http://www.diyautotune.com/tech_articles/installing_megasquirt_in_parallel.htm

All inputs are welcome. Thanks,

 
Based upon reading the MS article on parallel installation I think your only installation issue might be the drive by wire. If you use a volt meter to measure the output voltage on the gas pedal / throttle box used on the 2003 hemi and confirm that at closed throttle position it measures near 0 volts and at WOT it measures near 5 volts you can probably get it to work.

My only concern might be if the computer in some situations closes the throttle plates in response to some situations even though you are pressing on the throttle. Thus, you could end up in a situation in which the Mopar computer is closing the throttle plate, while the MS3 computer thinks the throttle is WOT and pouring in more fuel.

If this occurs frequently you would then be forced to ditch the drive by wire and go with a cable operated throttle body. Of course by your post, it appears you've already figured that out.

Regards,

Joe Dokes
 
Joe Dokes said:
Based upon reading the MS article on parallel installation I think your only installation issue might be the drive by wire. If you use a volt meter to measure the output voltage on the gas pedal / throttle box used on the 2003 hemi and confirm that at closed throttle position it measures near 0 volts and at WOT it measures near 5 volts you can probably get it to work.

My only concern might be if the computer in some situations closes the throttle plates in response to some situations even though you are pressing on the throttle. Thus, you could end up in a situation in which the Mopar computer is closing the throttle plate, while the MS3 computer thinks the throttle is WOT and pouring in more fuel.

If this occurs frequently you would then be forced to ditch the drive by wire and go with a cable operated throttle body. Of course by your post, it appears you've already figured that out.

Regards,

Joe Dokes
Click to expand...

Joe, the output from the APPS unfortunately sends it's signal to the PCM for processing. Then the PCM outputs the signal to the TB. I'm hoping this is only to control the cruise and not affected by rpm or speed limiters. If the PCM is jumping in when not wanted then I have to go cable drive for sure.

Thanks,
 
You mentioned you want the megasquirt to control the knock sensors. Do you have a gameplan for that? The last time I looked into that, it looked difficult.

How you get your throttle position sensor to work, and if you're able to make use of the idle air control will be the difficult stuff in my opinion (with the factory TB). And getting knock control. I would love to figure out the knock control aspect for the Hemi (teach me how?).

You can go without idle air control if that proves difficult. My install will be without it.
 
I'll be the first to say I don't have all the answers, but I'll certainly put forth the effort the best I can to solve problems. Here is the information I'm using for knock.
http://www.msextra.com/doc/ms3/ignition-settings.html#knock
I believe there are advances even since this was written. And the tuner studio looks to me to have the ability to tailor the knock control very specifically. But may require replacing the OEM knock sensors. From what I understand there is little problem in sharing signals from crank, cam, tps and IAT. But ECT can be a problem due to some vehicles have two circuits involved. The simple solution is to add a second sensor if the OEM sensor doesn't want to play nice. My 03 needs these inputs and others from the OEM PCM to operate the TCM for trans control. My trans is stock with a stage III valve body, line booster and edge 2800 TC. I use a floorshifter when playing hard. I'm happy to share what little I know and of course look forward to hearing from folks that have already done any of this.
Thanks,
 
I'll be running 2 coolant temp sensors (one for gauge and one for megasquirt). I just bought the sensors that the megasquirt is calibrated for (coolant temp and Intake temp). DIYautotune.com. under $20 each.

I read a good bit of that knock article. Very cool! I had read something else at one point that was much more confusing, and seemed a bit more complicated (might have used our factory sensors).

My plan for knock control was to listen for it.
http://autospeed.com/cms/title_DIY-Detonation-Detection-Part-2/A_0353/article.html
and part 1 of that:
http://autospeed.com/cms/article.html?&A=0348

Here's another link I found along the way:
http://home.netcom.com/~bsundahl/knock/sound/KnockSounds.htm
 
Just reading but a Det Can seems very effective means to listen for knock. Basically a 3/4" copper pipe with a cap on one end and the other end pounded flat with a hole in it to allow it to be bolted to the block. The end with the cap has a hole drilled to insert a heavy rubber hose which can be fairly long connected to a pair of muffle type hearing protectors. Run the hose into a "Tee" and then the two hoses into holes drilled in the hearing protectors. Making it a stethoscope that surpresses surrounding sound. Seems simple enough.

Here's link of a similar one, but the idea is the same.
http://forums.neons.org/viewtopic.php?t=295450
 
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