ParadiseMJ

I have questions about the VSS (Vehicle Speed Sensor) mounted at the rear of the AW4 tranny...as touched on in this thread. http://comancheclub.com/topic/40598-91-speedometer-issue-does-not-read/page-2 How crucial is this particular sensor to the shifting "timing" of the AW4. Mine is shifting too soon. Other than it shifting too soon...once it gets up and going it seems to run and lock/unlock/downshift properly. As Hornbrod mentioned the testing is not all that reliable. So how would one know if it is functioning properly or not, short of just throwing a new one in there??

:popcorn:

So THAT's how it happened!!!

So's not to jack this thread I'll send you a PM...but I did wonder about "shift logic"...see below, I sometimes need short words.

OMFG...be careful what you wish for... :doh: I don't have a Power mode as the tranny is from a 94. I swapped it in after my Peugot 5 speed took a dive on me. It's been a wiring debacle...until I swapped in a new wiring harness (which was also a PITA). I didn't have all the parts and pieces I needed. I'm just getting it dialed in after about 6 months of futzing with it (not my DD thankfully). My XJ has the original AW4 and it truly has been bullet proof...no tranny issues. Still has Power/Comfort switch. I think the MJ throttle valve cable is adjusted properly...as I've messed with it several times, had it disconnected/reconnected/tweaked etc.

:popcorn: Not hijacking here, but I have exactly the opposite problem. Mine shifts from 1st to 2nd to 3rd all before I hit 35 mph. So, I'm watching how you resolve this!

Did you plug the vac lines on the CAD servo. Is the linkage on the t-case properly adjusted?

WHEN you get it out... I used self tappers to put it back in. Works fine, been there for years, don't have to mess with those pesky weld nuts. If I don't have to re-use them I always re-move them.

It is not rocket science. The cable connector is just a square cable end on either end that fits in to a square receiver, gear turns, cable turns, speedometer indicates speed. Here is a basic idea of what you're looking for. It's held in to the tranny by one bolt...on the fork. Remove the bolt, wiggle and pull the speedo gear housing out of the tranny (don't worry about anything spewing out of the tranny, it won't. http://www.jeepz.com/forum/attachments/drivetrain/1299d1211769361-speedometer-gear-replacement-jeep-tj-picture-007.jpg When you pull it out, it will all come out including the speedo gear. Then unscrew the cable from the housing, you should see a square cable end like this. http://thumbs3.ebaystatic.com/d/l225/m/mMPZIXVnuqamVidfNA2Uy9A.jpg Don't pull on that...it will come undone at the speedometer end if you do. Just try to jam the square end back in to the GEAR part, and put it all back together. Then drive and see how it works. If it doesn't, either your cable is broken or the square part at the speedometer end is messed up.

Resolution: I had done the sensor ground wire upgrade on the OLD wiring harness. When I replaced the harness...I did the same upgrade on the new harness...except I missed one of the ground wires. I tore open the new harness that I had all neat and tidy...and found the wire. I tacked it to the 3 grounds with a dab of solder, and it started right up. So I soldered it all together, shrink wrapped and taped it, put it all back together. Went for a drive. The good: It runs fine, I have a spare CPS (previously thought bad), my NSS and tranny wiring is good and tight (my back-up lights even work). Plus I can now swap out a CPS in about 20 minutes. The bad: I spent a couple days #$@^ing with this for a stinkin' 16 ga. ground wire. The tranny still does not shift quite right. Starts out in 1st, shift at 2K RPM into 2nd, then 3rd all in about 200 ft. So I still need to dial in the TPS and looking at it I've realized it's an Airtex. I might wanna swap that out, or even put the spare back in until I get it figured out.

Is it 2 wheel drive? You might wanna put info about your specific model that in your sig line. for future reference

Break peddle is my favorite.

Have you removed the gauge cluster or the transfer case lately? If not, it's likely your speedo cable is broken...or somehow came out of the square cable keys on either end. You can remove the transfer case speedo gear housing and take a look at the cable, spin it, see if it affects the speedo.

There is that. Too late, it's at the landfill. After I saw the wire insulation was melted and I had the new Jeep CPS in hand I thought I had the "fix". So into the trash with the melted one.

OK... Here we go again. All the testing of the CPS has been done. Still get only .1 or .2...I also verified that the cylinders are getting fuel. Then I drilled it out and pressed it into the bell housing and tightened up the bolts. Tested the VAC again...got either 0.00 or an intermittent .1. So that CPS is toast, can't return it. Since the CPS seems to be the issue and not necessarily the new wiring bundle since the CPS is independently testing bad...right?? If the CPS tested good, and I still wasn't getting a spark, I'd go to the coil or ICM. Is there any other reason the CPS would test bad. I even took a look at the flexplate when I was recovering a lost CPS bolt :shake: . The flexplate is clean as a whistle. Remember, this is a Jeep Dealer CPS I'm really tempted to just go to AutoZone and get a cheapo CPS.

:thumbsup:

Yes, got drill...since the thing isn't "testing" right (within spec...and not working, I figure what do I have to lose in tweaking it. It was still working when I removed the old harness...BUT...when I checked it out, I realized the insulation had melted (but it WAS working)...which is why I endeavored to replace it. When I replaced the harness it did NOT work, I figured it had finally given up the ghost. I actually have a "trail" spare, but what with the PITA in replacing the sensor itself, I want to be somewhat sure that I have a GOOD one.

After perusing the TSB and checking the old harness and the new harness, the CPS mod has not been done on either Jeep. Wires and connectors are identical, so it should be plug n' play...I'll have to spend a bit more time testing before I give up the ghost on the new CPS. If anyone has another idea, lemme know. So is it at all possible to either INSTALL it incorrectly or a way to test and tell if the CPS is good before I even bring it home?? ...

I may be starting to sound like a certain BMW/Jeep owner on "another forum" but the TSB (1 page) strikes me as somewhat vague on how the kit connects "directly" to the ECU. EDIT: OK I found the full version of the TSB and the fix. (6 pages) I don't believe this was already done on the donor as I simply unplugged everything and there was no "extra wires" at the ECU, but I'll look at the discarded harness. I'd rather NOT do this fix...but if I have to get this thing going I will. http://wagoneers.com/XJ/tech/CrankPositionSensor-87-90.pdf

That's .1 VAC BTW, not .01 unless I'm doing this wrong. It doesn't seem like I did it the right way...since I'm getting such weird readings. Like I said, brand new from Jeep dealer. I'd expect it if I got the thing from AutoZone. So how would I test the wiring from the C101 TO the connector from to see if I'm plugged in to a dead circuit on the vehicle (harness) side.

CPS reads 241 on 2K ohm scale. .01 on VDC No spark at coil By the way...what CPS mod? The plug I'm plugging in to is the same plug I've been using all along. I kept that side of the C101 connector, I kept all the injector wiring as it was.

The CPS is brand new from the dealer. I will test it and the wiring again, as well as testing the wiring coming IN to the CPS. Replacing the CPS is/was a total B%$@!. I've done it before and it's only taken me about 30 minutes...this time was contortionism gone awry, in the rain, on a gravel driveway. I'm gettin' too flippin' old for this. Fire means it won't "fire up". I'm sure I have NO spark as I can hear the fuel pump prime and I tested the fuel pressure, with a gauge. I ran out of light (and patience) last night. I will test for spark today. My battery is suffering for all of this so it's on a charger as I type until I get home from work today. Don't know if that'll make a difference. The grounds on the dipstick are brand spankin' new, new bolt, new connectors, soldered. Tight and right. As far as the donor harness. I spent about 4 hours cleaning it, checking every connector, no bent pins, repaired all the "bubble gum" grounds with solder, shrink wrap AND tape. I was really meticulous about it . I super cleaned the C101 connector (both sides) and shined up every single thing I could find to shine.

I finally got fed up with trying to finagle the wiring for my MJ, the AW4 swap, shifting issues, missing switches, lighting etc. etc. So, I scored a complete engine side wiring harness...same year, same set-up, 4.0 AW4... from C101 to A/C to TCU to ECU...I just unplugged it from the donor and plugged it in to my truck after I fixed all grounds, cleaned all the connectors. I kept the injectors wiring from the C101 from my harness intact. So, I got it all plugged in, checked the back-up lights, only starts in P or N, I also replaced the CPS and all four relays (RENIX), checked all the lighting...all good. Fuel pump primes, pressure at Schrader valve good, tested the tranny solenoids at the TCU connector, all good. One problem left...IT WON'T START!!! Cranks fine...no fire. Help me Obi-Wan

I re-read the brake cleaner can. The warning that HAD been on there when I noticed it a year or so ago...was either changed or removed. The new cautionary wording is that it "may cause damage to plastics" and "do not spray on "energized electrical components" (duh). I'm using Dawn on the wire part, QD electric cleaner inside the connectors. I can't believe how stinkin' greasy this stuff is. Obviously 25 years of grime, which I hope doesn't affect the performance of the wiring itself. I also find it incredible that they pasted the sensor grounds together with "chewing gum" and duct tape. If anyone has NOT done Cruiser's sensor ground upgrade...do it. I'd bet just that could cure a lot of electrical gremlins I experience and read about.

So, then just soap & water? :smart: + :( = :dunce: