Jeep 4.0 or more accurately a 4.6 STROKED 4.0 with Jeep injection hardware???

[EagleMark]

This one has 2 wires...

[JeepsAndGuns]

There is a 1 year only (1991) VSS thats diffrent. 91 was the first year of the 4.0 in the YJ and the 91 model still had a mechanical spedo. It used a two wire VSS that screwed onto the t-case and cable onto it, exactly like the JTR ones. I cant be 100% sure, but I think all the 91-95 ecm's will interchange. Not sure where the wires go from the 2 wire vss, as I dont have the wiring diagrams for the 91 model. But the 3 wire one used on all 92 and up, might have a diffrent signal that will run the speedo, but also still give the proper signal to the ecm. Guess the only way to know for sure what signal they send is to test one?

[EagleMark]

I have seen a picture of that one when we were trying to find a JY VSS and it had a large speedo cable on one side and a smaller one on other so I assumed it would not work. But this one has small speedo on both sides and a plastic addpater sleeve that screws on to make it correct size. So it may be that one.

It is sold by Transmission Center and I looked on their site and sure enough 8 PPM and it comes in middle of speedo cable they sell. It says good for aftermarket speedo and EFI but not sure which EFI?

I have not had time to test and don't know how? Even if I could use 8PPM is it correct signal and I would have to break out Osiliscope to see the signal and don't even know what kind of signal GM ECM/PCM is looking for? It's an Automotive MAC osiliscope so it may have comparitable views of signals for these sensors. Nice feature of this Osiliscope is it has what each signal is supposed to look like!

[cmaje72]

I am using the VSS that came with my 89 Wagoneer on my LT1. I am running the oddball '93 F-Body ECU (DA3) that is more like the older ones. It is 8PPM. All I did was change the road speed constant from 4060 to 8120 and it works great.

[EagleMark]

Well that seems to answer my question. Thanks cmaje72!


Did you just wire the 2 wires directly into PCM? Or use a DRAC/VSSB?

BTW I found your message, don't know why I missed it, then lost the number so please call again.

[cmaje72]

Nope no DRAC just directly to the PCM. I'll have to go out and look at it because I can't remember exactly how I wired it in. I think that stock my ECU is looking for a 4000PPM sine wave signal.

[JeepsAndGuns]

With this 3 wire one thats on my yj having a power in, would that change the type of signal it outputs? If you have a way to measure/test one, give me a couple weeks and I can pick up a spare one at the pull a part for cheap off of a dime a dozen XJ cherokee, I can send it to you and let you test it. Its the same as the one on my YJ.

[cmaje72]

From memory the 3 wire VSS on some chrysler products has a power (5v), ground, signal wire. The output for these is 8000PPM square wave. What ECU are you guys trying to use and what is it expecting? I guess I will have to go back to the beginning of this thread and read.

[doc65]

With this 3 wire one thats on my yj having a power in, would that change the type of signal it outputs? If you have a way to measure/test one, give me a couple weeks and I can pick up a spare one at the pull a part for cheap off of a dime a dozen XJ cherokee, I can send it to you and let you test it. Its the same as the one on my YJ.

Jeeps,

I think that you'll find that the one on an XJ is different, specifically it has the e-connector out, but doesn't pass thru the mechanical speedo...

[EagleMark]

From memory the 3 wire VSS on some chrysler products has a power (5v), ground, signal wire. The output for these is 8000PPM square wave. What ECU are you guys trying to use and what is it expecting? I guess I will have to go back to the beginning of this thread and read.

Well it started as jeep, but threads usually run astray, we turned to GM ECM swap in middle, I am asking for GM ECM 16197427.

[JeepsAndGuns]

I have been talking about using a 1227727 ecm to run a jeep 4.0.

Doc, my YJ uses the 3 wire vss and has no spedo cable. Only the 91 model year wranglers use the cable and pass through vss. (91 is the first year for the 4.0 in them, and same basic mpfi system on the 2.5) I do not know about the XJ's of the same year.

[doc65]

I actually knew it was a 91 only thing in a YJ, but a cross reference shows it's also used on like 88-94 Dakotas. The 91 XJ does not pass mechanical thru, I have the engine and trans from one here that I pulled out of a 91 XJ as a transplant into an Eagle candidate, I vaguely remember taht my 88 & 89 XJ's may have had a speedo cable, so they might have used a pass thru VSS...

[doc65]

Anyone got a suggestion on a well supported ECM that will run the Jeep MPI and do DIS and alternately one that would do TBI on a 258 with DIS(I know odd combo)

[EagleMark]

The 16197427 and variants comes with TBI and CPI and has hacks for MPFI. We have had some discussion about DIS and it seems possibal any ECM can do this with right parts and settings...

[doc65]

Mark,

CPI? Any ECM will do DIS? I guess I'm missing something in that. Also what is involved in this hack for MPFI that you mentioned?