A dual PCM system would be workable, but, switching the hundreds of circuits would be problematic. I also think it would require shutting down the engine, switching PCMs, and then restarting. Probably. Odometer memory could be a problem....... might work better on 94-97 systems. (mechanical odometer.)

 

That's not stupid, but yes, it sounds impossible. Maybe after market PCMs that are custom designed to do so but now your talking more money than this whole idea is worth. Might as well spend that money on a ProCharger lol

 

Megasquirt...

 

Dude.....thank you. That is bada$$. You run one if these? That looks like one hell of a fun but difficult project.

 

Yes I do. It can do dual fuel and/or spark tables, which can be switched a few ways, including a toggle switch. It would be easy to take the stock PCM coil negative wire and hook it directly to the MS box then output the exact same timing as the PCM to the coil by leaving the spark table all at 0, then adding timing where you wanted it in the second table. I eventually plan on taking over timing like this except to retard it for boost instead of advance it, currently the Mopar PCM and a MSD BTM takes care of the ignition side of my setup and MS just controls the injectors, E-fan and shift light.

 

So how much does a system like this run? And since I've never done something like that how difficult is it to learn?

 

I think MS2 3.0 is like $250, you'll then want a harness which is around $80 I think now, and CLT and IAT sensors. A wideband is very important (~$200). It starts to sound like a lot but for a standalone computer than can run anything, it's a bargain. Check out DIYAutoTune.com.

I fad mine installed fuel only in about 3 hours, after I figured out I tapped the wrong wire for injector power I had it up and running and drove it to work the next day, of course the tune was nowhere near perfect but it was driveable. Then I just spent a bunch of time tuning it and getting it where I wanted. It's been in there over 13 months and over 20k miles. I highly suggest reading the megamanual a lot. It's is a pretty steep learning curve but if you commit to it the results are awesome.

 

I am talking WHEN YOU ARE NOT RUNNING WATER/METH.
You can't reprogram your PCM while you are driving and a SCT cannot be programmed to reprogram "on the fly" when any switch shuts something off.

YOu would need to pull over, and switch tunes from your SCT. So if you think that "the system" will notice and correct yourself from only ONE tune, then yes, you are wrong. You cannot program two different fuel parameters with one tune.

 

BTW, I was going to recommend SAFMS (Megasquirt) but I didn't want to steal Hans' thunder....since he actually runs one.

But you can't do it with a SCT and a stock PCM.

 

So then I go with Hahns suggestion and built an ECM that I program around the water methanol injection...

From what I've read, you can incorporate a knock sensor using the MS computer too...