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AW4 Delayed Shifting...

CommandoXJ96

NAXJA Forum User
Location
Tucson
It seems to be delayed in up-shifting now... (downshifts alright from what i can tell) It will hit say 4000 RPM (and not move much) and just sit there for a bit before it goes from 2nd to 3rd gear. With the skinny pedal down it does this for every shift it seems - but when I'm taking it really easy it doesnt seem to be much different. Somethings changed... bad tps maybe? thats what i'm thinking it is - thought I would ask some other xjers before I went ahead and spent money on that though. Also, I found ways of checking(and adjusting) ReniXJ tps's - how do you just check a 96?

96, 4.0,Aw4,242
 
well... 94 tps's work in 96's. and damn well might i add. I know someone who should have taken their XJ to work today instead of leaving the key where i could find it. (he might not drive it for a couple weeks... i'll tell him about then.)
 
well this is like my 5th post on my own thread (basically turned it into a monologue).... I guess its not fixed - but the issues not the TPS I know now. Seems as if it will sit at the highend rpm of the gear and not change for a bit as I said, and then after the delay, it slams into the next gear - very hard shifts. Anybody got any ideas?
 
well i did an atf change and lucas oil treatment. seems nothings changed - it still shifts wonderfully at light to medium throttle. I don't think anythings clogged.... is there anything else that could be cuasing it to act up assuming its not the transmission fluid doing anything? my dads XJ really goes off the line and shifts wonderfully, mine tho on 31s instead of 235s (which accounts for some load and loss of speed) seems to shift at crappy times compared to it. His will redline and shift to 2nd etc... Mine will hit 4000ish RPMs and just sits there (cat rattling noise - which is getting replaced monday) and then shifts after ... well it seems to be forever. Its got me a bit confused.
 
I'm still battling mystery shift problems in my AW4. My next step is replacing the TPS sensor (even though it checked out a-ok). All of my local parts places want $150+ for a new TPS..where do you guys get them for 50 bucks?!?!?

My problem is more with random shifts. It'll accelerate fine, shift at 2200RPM or so, everything will be fine but then out of the blue it will start downshifting or upshifting at highway speeds. I stopped driving it on the highway for the time being since it did it a few times..it'll go from OD to 3rd, redline a bit then go back to overdrive. Or 3rd to 2nd same deal.
I wish I knew what it was. Everything points to a faulty TPS unit since it occurs randomly, but I can't bring myself to shell out $150 for a new TPS since mine tests out okay!
 
Team Cherokee can get you closer to the 50 dollar range I believe.

http://cgi.ebay.com/ebaymotors/91-9...ryZ33557QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

edit: i seem to remember you have a 1990? if so.. Rock Auto has a TPS for like 55 dollars I believe.

It seems to me after more driving of both cars... that the cherokee without the 'problems' (not mine :|) accelerates and hits the redline in 1st gear almost right away... and keeps on that trend throughout the gears when its at WOT. Mine at WOT just sits at 4K Rpm!!! It's driving me nuts... I'm thinking it has nothing to do with my transmission now. Becuase I shift at the right spots at WOT - but at WOT it just takes forever for the XJ to climb up from 4000 rpm to the shifting sweet spot. Nothings is pointing me to TPS anymore and I've already adjusted the TV Cable. Could it be something as simple as I need a new cap, rotor and wires becuase I'm not accelerating that last 700-1k rpm as quickly as it should? I can tell you right now that in a quarter mile the XJ im borrowing for comparison would be done before I hit an 1/8 of a mile. And that XJ is completely stock. And my XJ runs smooth, great idle, no missing knocking... anything. Just seems its lost alot of power - right after it hits 4K rpm. Is it possible that my bad cat would effect this either? I hope somebody chimes in b/c I'm really lost.
 
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this may seem like a dumb question... (and it is... and I laughed when it hit me) but which sensor is on the Passenger side of the Throttle Body? Thats not the Tps? Is it... its gotta be the one on the aft-side of the tb huh? From the picture online I looked at I think i got myself confused :) maybe its time to try tradeing the "other" Tps. This is the first time I've touched any of the sensors.
 
the other one on the throttle body is the IAC a.k.a. Idle Air Control sensor. It can get gummed up and cause run-on and funky idle. Carefully remove it via the two torx screws and clean the pintle or "nub" with sensor-safe solvent. Be carefull with it as the pintle can easily be damaged.
 
oh, i didnt make it clear in that other post at all, I swapped out the IACs between XJs thinking it was the tps... Now I have to try swapping the real TPSes. I thought it was funny becuase of how stupid I am sometimes.
 
clunk said:
the other one on the throttle body is the IAC a.k.a. Idle Air Control sensor. It can get gummed up and cause run-on and funky idle. Carefully remove it via the two torx screws and clean the pintle or "nub" with sensor-safe solvent. Be carefull with it as the pintle can easily be damaged.
Just for clarification, the IAC is not a sensor, it is a control motor, a motor operated air valve. It changes the idle air flow rate in the throttle body.

Sensors send data to the ECU (computer) then the ECU sends signals to the control devices like the fuel injectors, IAC, and ignition control module.
 
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CommandoXJ96 said:
It seems to be delayed in up-shifting now... (downshifts alright from what i can tell) It will hit say 4000 RPM (and not move much) and just sit there for a bit before it goes from 2nd to 3rd gear. With the skinny pedal down it does this for every shift it seems - but when I'm taking it really easy it doesnt seem to be much different. Somethings changed... bad tps maybe? thats what i'm thinking it is - thought I would ask some other xjers before I went ahead and spent money on that though. Also, I found ways of checking(and adjusting) ReniXJ tps's - how do you just check a 96?

96, 4.0,Aw4,242

My 87 XJ, AW4, 4.0 shifted up at WOT at about 2000 to 2,200 rpm for the first three years I owned it! During that time I replaced everything but the engine, transmission, ECU and TCM.

I recently set the transmission cable on the throttle body as per the FSM and it now shifts up at about 3,000 rpm while at WOT. It has never gotten close to red line.

So I am wondering what is a normal shift point for the AW4 at WOT??????? :dunno:

I suspect it is closer to 3000 rpm than red line!!!!!!
 
well on my dads HO XJ at WOT its very close to 5K. I do know for sure that mine is behaving very differently from his as it will hit and then sit at 4k rpm for 5 or 6 seconds before shifting. I know that at less then WOT it is alot lower - around or below the 3k mark. I'm not sure what the shift points are supposed to be though - seems all the XJs we are talking about have different ones for some reason.
 
The only time I had any tranny problems on an AW4 was when I went to a 31" tire
I bought some rubicon rims with the Goodyear stock 245/16's (equivalent to 31")
about a month after I installed them I notice my shifting started acting up, ie. slipping and delayed shifts
The transmission was well maintained flawless before that
I didn't have a chance to go back to a smaller tire because i sold the Jeep
 
Ecomike said:
My 87 XJ, AW4, 4.0 shifted up at WOT at about 2000 to 2,200 rpm for the first three years I owned it! During that time I replaced everything but the engine, transmission, ECU and TCM.

I recently set the transmission cable on the throttle body as per the FSM and it now shifts up at about 3,000 rpm while at WOT. It has never gotten close to red line.

So I am wondering what is a normal shift point for the AW4 at WOT??????? :dunno:

I suspect it is closer to 3000 rpm than red line!!!!!!

My 87 4.0 shifts at about 5k when at WOT.

It also behaves like Commando96's when the transmission mount is worn or the throttle cable needs adjusting.
 
well well, I wonder if my shifting problems are due to a worn or loose tranny mount. I noticed it'll sometimes "clunk" into or out of gear when stopping and I wonder if this is due to a worn mount. Another piece to the puzzle.
 
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