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megasquirt2 on grand cherokee 5.2 (zj)

Posted: Thu Oct 12, 2017 3:26 am
by christahiti
hello, I'm Chris, from Tahiti, I own a jeep grand cherokee zj from 1994, v8 5.2 SE.
I plan to buy a MS2 in order to swap the stock ECM. does anybody done it before?? It will be my first experience with ECU programming, did someone done it with success with the same car? the automatic transmission is the 46 RH and I would know if it will be a problem with my project.
thanks for your answers!!!

Re: megasquirt2 on grand cherokee 5.2 (zj)

Posted: Thu Oct 12, 2017 6:10 am
by Matt Cramer
We've got a '95 model with the same engine and transmission running an MS3Pro. The "RH" version of the transmission is not a problem; it's the "RE" electronically controlled variant that's trouble. These engines used an eight tooth flywheel trigger and a one tooth trigger in the distributor. This can be used to trigger a distributorless ignition as well, as long as you keep the distributor body, sensor, and trigger wheel.

These are the settings we used on the MS3Pro. They should also cross over to MS2/Extra.

• Ignition input capture: Falling Edge
• Trigger wheel arrangement: Dual wheel
• Trigger wheel teeth: 8
• Tooth #1 angle: 142
• Main wheel speed: Crank wheel
• Second trigger active on: Falling edge
• And every rotation of: Cam

Re: megasquirt2 on grand cherokee 5.2 (zj)

Posted: Thu Oct 12, 2017 9:48 am
by christahiti
thank you Matt for your prompt answer :D ! If I will go ahead with the MS2 and the wiring harness, do I need something else to see the GC run as it should? sensors? ignition components? in order to tune the MS2, does some files already exist for the GC?

Re: megasquirt2 on grand cherokee 5.2 (zj)

Posted: Fri Oct 13, 2017 5:46 am
by Matt Cramer
We were using 100% stock sensors other than a wideband O2 sensor system.

Usually once you get the default MS2 tune scaled for your engine and injector size, and configured for your ignition, you're 90% of the way to a good startup map. Copying an MS3 map to an MS2 is possible but could cause more confusion than it solves.