Aw4 Shifting Issue What Did I Miss?

[RockMJ]

Hey everyone, my 1990 Eliminator with the AW4 has never shifted on its own since I purchased it. I just wanted to know if there is something I am missing before I take the pan off and replace the two solenoids. Here is what I have done thus far:

 

- Cleaned, and dielectric greased harness plugs on firewall

 

- Cleaned, and dielectric greased the TCM harness plug and inline 10 amp fuse

 

- Replaced 10 amp fuse with new fuse

 

- Replaced blown 7.5 amp "Trans" fuse (Power Comfort Module)

 

- Adjusted trans kick down linkage to factory spec

 

Now when I bought the Jeep the PO said he power washed the Jeep and after he cleaned it the transmission would not shift. When I bought it I just unplugged the TCM and have been manually shifting the transmission without issue. The Jeep also (prior to what I listed above) would barely move in "D" like it was starting off in 3rd.

 

Since I did all the cleaning, new fuses, and adjusting the linkage the Jeep now has normal power in "D" and takes off extremely well. Here is where the next problem is. The Jeep refuses to shift out of first and will hold at 4K RPM for 15-20 seconds before the trans is forced into the next gear. This leads me to believe the shift solenoids are bad, but in the very off chance I missed something I was hoping someone could tell me. Thanks a ton,

 

RockMJ

[xjrev10]

For the heck of it did you try a different TCM?

[RockMJ]

Yeah, I did. I took one out of my buddies 90 XJ and it did the same thing. Forgot to mention that

 

RockMJ

[ParadiseMJ]

: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!

[RockMJ]

Is your linkage on the throttle body adjusted properly? My XJ had a similar issue when I bought it and a simple adjustment fixed everything. 

 

RockMJ

[RockMJ]

Not to sound totally ridiculous here, but if I bypassed the Power/Comfort switch is there a chance it would solve my issue? I know its a long shot, but I can try it and see how it does I suppose. From experience the Power mode in my past Jeeps had it shift around the higher rpm range, but I still think mine sticking at 4K RPM's for 20 seconds its a bit much. I am going to also clean out and re-grease the TPS connectors in the off chance it is them. I have to find my ohm meter so I can test the TPS further. Just trying to work this issue all out as it could be any number of things. 

 

RockMJ

[RockMJ]

: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!

 

Forgot to ask if you have tried it with the Power mode selected and if it made a difference? I wish I had your problem lol

 

RockMJ

[cruiser54]

Not to sound totally ridiculous here, but if I bypassed the Power/Comfort switch is there a chance it would solve my issue? I know its a long shot, but I can try it and see how it does I suppose. From experience the Power mode in my past Jeeps had it shift around the higher rpm range, but I still think mine sticking at 4K RPM's for 20 seconds its a bit much. I am going to also clean out and re-grease the TPS connectors in the off chance it is them. I have to find my ohm meter so I can test the TPS further. Just trying to work this issue all out as it could be any number of things. 

 

RockMJ

 

It could help. Here's how to do it.

 

Bypassing the Power/Comfort Switch on a Renix Jeep

Remove and unplug the switch. In the harness are 3 wires One has a stripe, one is tan, and the other black. Make a 4" jumper wire with a male spade at each end. Plug one end in the cavity for the tan wire and the other in the cavity for the striped wire and you'll be in permanent Power mode. Stuff the harness back in and reinstall the switch for looks.

 

You could have a TPS that's bad on the "trans" side also.

[ParadiseMJ]

Forgot to ask if you have tried it with the Power mode selected and if it made a difference? I wish I had your problem lol

 

RockMJ

 

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. 

[cruiser54]

Paradise, what about the signal from the speed sensor that sends a signal to C3 of the TCU? White w/brown at sensor through connector C114 to a tan w/tracer at c3 on TCU.

 

C114 is the 8 pin connector at the rear of the valve cover.

 

Shift point logic ground  goes from C5 of the TCU to the engine dipstick tube stud ground along with the road speed sensor ground and and solenoid grounds..

[RockMJ]

 

Not to sound totally ridiculous here, but if I bypassed the Power/Comfort switch is there a chance it would solve my issue? I know its a long shot, but I can try it and see how it does I suppose. From experience the Power mode in my past Jeeps had it shift around the higher rpm range, but I still think mine sticking at 4K RPM's for 20 seconds its a bit much. I am going to also clean out and re-grease the TPS connectors in the off chance it is them. I have to find my ohm meter so I can test the TPS further. Just trying to work this issue all out as it could be any number of things. 

 

RockMJ

 

It could help. Here's how to do it.

 

Bypassing the Power/Comfort Switch on a Renix Jeep

Remove and unplug the switch. In the harness are 3 wires One has a stripe, one is tan, and the other black. Make a 4" jumper wire with a male spade at each end. Plug one end in the cavity for the tan wire and the other in the cavity for the striped wire and you'll be in permanent Power mode. Stuff the harness back in and reinstall the switch for looks.

 

You could have a TPS that's bad on the "trans" side also.

 

Cruiser, excellent information thank you! Is there any way to test the transmission side? I am going to take all the connectors off and clean and regrease them this weekend. I am going to ohm out the TPS when I do it and try to get it as close to spec as possible. I believe its off of the A-D that gives you the reading with the ignition on and the plug disonnected to as close as 5.00 as possible with the throttle completely closed, then from B-D to get the actual reading that you will be adjusting off of? It is something like 82 or 83% of the initial A-D reading IIRC. It has been a while since I have done one so I will have to look up some info on the proper procedure. Thanks guys,

 

RockMJ

[RockMJ]

 

Forgot to ask if you have tried it with the Power mode selected and if it made a difference? I wish I had your problem lol

 

RockMJ

 

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. 

 

Yeah, true I don't want 6 months of issues haha. I just want the transmission to shift on its own without the engine sounding like its going to explode at 4200 RPM. I will post up if the TPS helps my issue. If not, its back to diagnosing and troubleshooting

 

RockMJ

[cruiser54]

 

 

Not to sound totally ridiculous here, but if I bypassed the Power/Comfort switch is there a chance it would solve my issue? I know its a long shot, but I can try it and see how it does I suppose. From experience the Power mode in my past Jeeps had it shift around the higher rpm range, but I still think mine sticking at 4K RPM's for 20 seconds its a bit much. I am going to also clean out and re-grease the TPS connectors in the off chance it is them. I have to find my ohm meter so I can test the TPS further. Just trying to work this issue all out as it could be any number of things. 

 

RockMJ

 

It could help. Here's how to do it.

 

Bypassing the Power/Comfort Switch on a Renix Jeep

Remove and unplug the switch. In the harness are 3 wires One has a stripe, one is tan, and the other black. Make a 4" jumper wire with a male spade at each end. Plug one end in the cavity for the tan wire and the other in the cavity for the striped wire and you'll be in permanent Power mode. Stuff the harness back in and reinstall the switch for looks.

 

You could have a TPS that's bad on the "trans" side also.

 

Cruiser, excellent information thank you! Is there any way to test the transmission side? I am going to take all the connectors off and clean and regrease them this weekend. I am going to ohm out the TPS when I do it and try to get it as close to spec as possible. I believe its off of the A-D that gives you the reading with the ignition on and the plug disonnected to as close as 5.00 as possible with the throttle completely closed, then from B-D to get the actual reading that you will be adjusting off of? It is something like 82 or 83% of the initial A-D reading IIRC. It has been a while since I have done one so I will have to look up some info on the proper procedure. Thanks guys,

 

RockMJ

 

RENIX TPS ADJUSTMENT

Before attempting to adjust your TPS be sure the throttle body has been recently cleaned. It's especially important that the edges of the throttle butterfly are free of any carbon build-up.

IMPORTANT NOTE: With the Key OFF, and using the positive (red) lead of your ohmmeter, probe the B terminal of the flat 3 wire connector of the TPS. The letters are embossed on the connector itself. Touch the black lead of your meter to the negative battery post. Wiggle the wiring harness where it parallels the valve cover and also over near the MAP sensor on the firewall. If you see more than 1 ohm of resistance, or fluctuation in your ohms reading, some modifications to the sensor ground harness will be necessary. The harness repair must be performed before proceeding. I can provide an instruction sheet for that if needed.

MANUAL TRANSMISSION:

RENIX manual transmission equipped XJs have only a flat three-wire TPS mounted on the throttle body and it provides data input to the ECU. It has three wires in the connector and they're clearly embossed with the letters A, B, and C. Wire "A" is positive. Wire "B" is ground. Key ON, measure voltage from "A" positive to "B" ground by back-probing the connectors. Note the voltage reading--this is your REFERENCE voltage. Key ON, back-probe the connector at wires "B" and "C". Measure the voltage. This is your OUTPUT voltage. Your OUTPUT voltage needs to be seventeen percent of your REFERENCE voltage. For example: 4.82 volts X .17=.82 volts. Loosen both T-20 Torx screws attaching the TPS to the throttle body and rotate the TPS until you

have achieved your desired output voltage. Tighten the screws carefully while watching to see that your output voltage remains where it is supposed to be. If you can't achieve the correct output voltage, replace the TPS and start over.

Sometimes, after adjusting your TPS the way outlined above, you may experience a high idle upon starting. If that happens, shut the engine off and reconnect your probes to B and C. Start the engine and while watching your meter, turn the TPS clockwise until the idle drops to normal and then rotate it back counterclockwise to your desired output voltage.

AUTOMATIC TRANSMISSION: RENIX automatic transmission equipped XJs have a TPS with two connectors. There is a flat three-wire connector, same as the manual transmission vehicles have, and it is tested the same as the manual transmission equipped vehicles, as outlined above—FOR ALL ENGINE MANAGEMENT RELATED ISSUES.

However, the automatic TPS also has a square four-wire connector, clearly embossed with the letters A,B,C, and D. It only uses three wires and provides information to the Transmission Control Module. THIS SQUARE FOUR WIRE CONNECTOR IS USED FOR TRANSMISSION/SHIFTING RELATED ISSUES ONLY. Key ON, measure voltage between "A" positive and "D" ground. Note the voltage. This is your REFERENCE voltage. Back-probe the connector at wires "B" and "D". Measure the voltage. This is your OUTPUT voltage. Your OUTPUT voltage needs to be eighty-three percent of your REFERENCE voltage. For example 4.8 volts X .83=3.98 volts. Adjust the TPS until you have achieved this percentage. If you can't, replace the TPS and start over. So, if you have an automatic equipped XJ your TPS has two sides--one side feeds the ECU, and the other side feeds the TCU.

FOR AUTOMATIC TRANSMISSION RELATED ISSUES: Check the square four-wire connector side of the TPS.

If you have ENGINE ISSUES check the flat three-wire connector side of the TPS.

For those with a MANUAL TRANSMISSION--the TPS for the manual transmission XJs is stupid expensive. You can substitute the automatic transmission TPS which is reasonably priced.

Revised 09-22-2012

[RockMJ]

Cruiser, thanks again man! I will tackle the TPS this week and go from there. Thanks a ton for all the input!

 

RockMJ

[cruiser54]

Keep us in the loop. Done the ground refreshing yet?

[RockMJ]

Keep us in the loop. Done the ground refreshing yet?

 

I have not. I actually have had about five hours of wrenching time on the Jeep so far as the Jeep is stored over an hour from my place. Would upgrading the oem grounds to a thicker setup be part of what you are referring to?

 

RockMJ

[cruiser54]

     Renix Ground Refreshing

The Renix era XJs and MJs were built with an under-engineered grounding system for the engine/transmission electronics. One problem in particular involves the multiple ground connection at the engine dipstick tube stud. A poor ground here can cause a multitude of driveabililty issues, wasted time, failed emission tests, and wasted money replacing components unnecessarily.

The components grounding at the dipstick tube stud are:

Distributor Sync Sensor, TCU main ground, TCU “Shift Point Logic”, Ignition control Module, Injectors, ECU main ground which other engine sensors ground through, Oxygen sensor, Knock Sensor, Cruise Control, and Transmission Sync signal.  All extremely important stuff.

The factory was aware of the issues with this ground point and addressed it by suggesting the following:

Remove the nut holding the wire terminals to the stud. Verify that the stud is indeed tightened securely into the block. Scrape any and all paint from the stud’s mounting surface where the wires will attach. Must be clean, shiny and free of any oil, grease, or paint.

Inspect the wire terminals.  Check to see that none of the terminals are crimped over wire insulation instead of bare wire. Be sure the crimps are tight. It wouldn’t hurt to re-crimp them just as a matter of course. Sand and polish the wire terminals until clean and shiny on both sides. Reinstall all the wires to the stud and tighten the nut down securely.

While you’re in that general area, locate the battery negative cable which is fastened to the engine block just forward of the dipstick stud. Remove the bolt, scrape the block to bare metal, clean and polish the cable terminal, and reattach securely.

Another area where the grounding system on Renix era Jeeps was lacking is the engine to chassis ground. There is a braided cable from the back of the cylinder head that also attaches to the driver’s side of the firewall. This cable is undersized for it’s intended use and subject to corrosion and poor connections at each end.

First off, remove the cable end from the firewall using a 15mm wrench or socket. Scrape the paint off down to bare metal and clean the wire terminal. Reattach securely.
Remove the other end of the cable from the rear of the head using a 3’4” socket. Clean all the oil, paint and crud from the stud. Clean the wire terminal of the cable and reattach securely.

A suggestion regarding the braided cable:
I prefer to add a #4 Gauge cable from the firewall to a bolt on the rear of the intake manifold, either to a heat shield bolt or fuel rail bolt. A cable about 18” long with a 3/8” lug on each end works great and you can get one at any parts store already made up. Napa has them as part number 781116.

A further improvement to the grounding system can be made using a #4 cable, about 10” long with 3/8” terminals at each end. Attach one end of this cable to the negative battery bolt and the other end under the closest 10mm headed bolt on the radiator support just forward of the battery. Napa part number 781115.

For those of us with Comanches, it’s very important to remove the driver’s side taillamp assembly to access the ground for the fuel pump. Remove the screw holding the black ground wire. Scrape the paint from the body and corrosion from the wire terminal. Reattach securely.

If you want to upgrade your grounds and battery cables in general, contact Jon at www.kelleyswip.com.  He makes an incredible cable upgrade for a very reasonable price.

Revised 03-04-2013
 

[ParadiseMJ]

Paradise, what about the signal from the speed sensor that sends a signal to C3 of the TCU? White w/brown at sensor through connector C114 to a tan w/tracer at c3 on TCU.

 

C114 is the 8 pin connector at the rear of the valve cover.

 

Shift point logic ground  goes from C5 of the TCU to the engine dipstick tube stud ground along with the road speed sensor ground and and solenoid grounds..

 

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.

[carnuck]

Could be throttle position sensor got wet. I'd readjust the TVS cable tighter to see if it changes

[cruiser54]

Could be throttle position sensor got wet. I'd readjust the TVS cable tighter to see if it changes

Please explain to all of us how adjusting the TV cable affects the TPS adjustment. And, how would that affect a wet TPS? And, who said the TPS got wet?

 

Do you purposely respond to people's posts hoping to send them down a dead end road? I'm totally baffled by your off-the-cuff nonsensical responses. How is this helping anyone?

[carnuck]

two separate things. There is a trans control bit in the TPS. Water messes them up. TVS being adjusted is different.

[cruiser54]

two separate things. There is a trans control bit in the TPS. Water messes them up. TVS being adjusted is different.

I'm very familiar with the operation of the TPS and the TV cable. I was Service Manager and Shop Foreman at a Jeep dealer from 1980 through 1992. I grew up with these Jeeps since they were new. My concern here is how you throw out inaccurate tidbits of info to unsuspecting posters and lead them astray.

[carnuck]

I throw out other possibilities to check that I have come across. Since the TVS cable was altered from the factory setting, I figured re-checking it wouldn't be a bad idea.

[cruiser54]

I throw out other possibilities to check that I have come across. Since the TVS cable was altered from the factory setting, I figured re-checking it wouldn't be a bad idea.

You throw out crap that most times doesn't apply and is off the subject matter. You're back-pedalling now, you know.

 

I feel we are here to help others, not lead them astray with off the cuff crap that wastes their time.

[RockMJ]

Hey guys. Yeah I have set the throttle kickdown linkage to both extremes with little to no difference in the driveability. My issue is likely electrical somewhere down the line and I ordered a new TPS sensor so I will be installing and calibrating it this weekend as well as the suggested refreshes to the Jeep. I will post up what I find out! Thanks a ton guys,

 

RockMJ