MSefi.com read only forum (Jan.15,2018)

MS2 v3
89 jeep cherokee
4.0
I did it! These jeep have a crazy tooth wheel on the flywheel. 66 teeth(including missing teeth)
20 teeth then 2 missing, three times per revolution. So The vr sensor sees 20 then 2 missing,twenty then two missing,twenty then 2 missing, every revolution.
Couldnt find wheel decoder settings anywhere so I guessed that the Ms simply counts tach signals(as set by the wheel decoder) then compares that to the number of cylinders set in the ecu to determine rpm.
Here it is, and IT WORKS!
22 teeth
2 missing teeth
11 delay teeth( tdc is at the 12th tooth after the gap)
22 skip teeth
Here is why it works. If you know more than i do about the actual codes(almost a certainty) please explain for us. But i figured that the ecu doesnt realize that the wheel has three tooth gaps, It just counts the tach signals coming out the wheel decoder. its kinda crazy to me but after each gap it creates the signal on the 11th tooth after the missing teeth then skips the rest until the next gap,11th delay parameter happens. Im sooooooooo happy because my stock flywheel/cranktrigger and VR sensor work perfectly for the MS. If I missed anything please post as im just so damn happy i had to say something and may have left something out!!!!

It works because the ecu see this as a 22 - 2 tooth wheel that is revolving at 3x the actual rpm. Check the rpm gauge in MT - I'm guessing it is 3x what it should be.

grippo wrote:It works because the ecu see this as a 22 - 2 tooth wheel that is revolving at 3x the actual rpm. Check the rpm gauge in MT - I'm guessing it is 3x what it should be.

On earlier code variants, the RPM reads correctly as the code sees it as a 22-2 tooth wheel with only one tach pulse per revolution instead of three tach pulses.

RPM is dead on. Cranking at about 150, I figured that it thinks its a 22 tooth wheel. Everything works just as it should! Just wanted to post so other renix jeepers would know as I havent found it anywhere else. Thanks guys!

I stand corrected. Matt did answer a post from way back when. You were right on! The delay teeth I got out of the factory renix/jeep EFI manual. Wth the dizzy locked and the flywheel only mounting one way this was the easiest ignition I ever!

sweet i thought about doing this myself i wanted to build a stroker and thought about putting a twin screw on top of it.
would be great because you could go to the junkyard and grab the coil on plug setup off a 00/01 cherokee 4.0

Yep thats next. The renix manual i downloaded has the voltage reading for every sensor on the thing. Im using the stock vr,iat,clt,tps.iac,knock and o2. I havent got her all tuned yet, just running from the bench. But hey its like the thing was built for MS. heck The aw4 tranny is the same toyota unit everywhere else and ive already got full manual control over it. I love my cherokees. All four of em!