How do I improve the TPS/ sensors ground circuit? - Jeep Cherokee Forum
Jeep Cherokee Forum


OEM XJ Cherokee Technical. All XJ Non-modified/stock questions go here
XJ (84-01)
All OEM related XJ specific tech. Examples, no start, general maintenance or anything that's stock.
Sponsored by:
Sponsored by:

How do I improve the TPS/ sensors ground circuit?

Reply
 
 
 
Thread Tools Search this Thread
Old 11-11-2011, 11:25 PM   #1
Junior Member
Thread Starter
 
Join Date: Jun 2011
Location: Western WA
Posts: 77

View sansocal's Photo Album My Photos
Year: 1989
Model: Cherokee
Engine: 4.0
Default How do I improve the TPS/ sensors ground circuit?

I am having shifting issues when the jeep is warm and the resistance for the TPS ground to negative battery post is about 1.9. I have a new negative battery cord and soldered together the 6 ground wires in the harness by the firewall. I also cleaned all the grounds from the firewall to block, and the connections by the oil dipstick tube.

Is there anything else I can do to make this circuit better?
sansocal is offline   Reply With Quote
Old 11-11-2011, 11:52 PM   #2
CF Veteran
 
DFlintstone's Avatar
 
Join Date: Aug 2011
Location: Nor-Cal Coast
Posts: 10,068

View DFlintstone's Photo Album My Photos
Year: 90,84
Model: Cherokee
Engine: 4.0,2.5
Default

Wheres Cruiser? We need one of those spotlight deals like they shine up to call Batman! Can you isolate it? Block to neg post. Body to ground wires ect...

Plenty have added a ground from the dipstick tube bolt to a stud below the shock mount. I added one from a small bolt on the AC compressor to the a radiator mount bolt.

I'm no wiz on this stuff but I noticed that the "NSS" does allot more than stop starting in gear. Guess it also gives signals to the TCU. It seems to fail allot as a NSS, no idea if its common to cause shifting issues, but it stands to reason.
DFlintstone is offline   Reply With Quote
Old 11-12-2011, 05:40 AM   #3
::CF Moderator::
 
cruiser54's Avatar
 
Join Date: Aug 2011
Location: Prescott, Az
Posts: 34,620

View cruiser54's Photo Album My Photos
Year: 1990
Model: Comanche
Engine: 4.0
Default

Didn't I post that yesterday?

Anyway the ground circuit you tested was on the flat connector, right? That only affects the engine. The square connector is for the trans. Your TPS is really two TPSs in one and has separate potentiometers in each side to give info to two seperate control units.

My recommendation as far as shifting issues is to test the square connector per the instructions. Even before that I would find the trans control connectors over by the trand dipstick tube. They're kinda large and one is black and the other gray. Unplug them, spray out both sides with electronics cleaner, inspect for bent pins and plug them back in. All the info between the trans, NSS and TCU travel through those connectors.

As far as the 1.9 ohms of resistance in the sensor ground circuit, I have a fix for that which requires soldering. Let me know.
cruiser54 is online now   Reply With Quote
Old 11-13-2011, 11:18 PM   #4
Junior Member
Thread Starter
 
Join Date: Jun 2011
Location: Western WA
Posts: 77

View sansocal's Photo Album My Photos
Year: 1989
Model: Cherokee
Engine: 4.0
Default

I am attaching an excel sheet with the resistance values I found today.



Before I go any further I have three questions:
-I am assuming the resistance goes up with the key on because there is all that energy running from all those sensors, would a new (and thicker) ground strap be less affected from the juice, and keep a better ground potential ALL the time?

-Can I just run a cable from block to frame and solve all my issues?
Attached Files
File Type: doc Untitled 56.doc (18.0 KB, 53 views)

Last edited by sansocal; 11-13-2011 at 11:23 PM.
sansocal is offline   Reply With Quote
Old 11-14-2011, 05:13 AM   #5
::CF Moderator::
 
cruiser54's Avatar
 
Join Date: Aug 2011
Location: Prescott, Az
Posts: 34,620

View cruiser54's Photo Album My Photos
Year: 1990
Model: Comanche
Engine: 4.0
Default

My rule of thumb when checking these is to have teh key on when checking voltage, key off when checking resistance.
Your sensor ground circuit is a little high. Less than 1 ohm is what you want.
To simplify the general grounding issues with these Jeeps I do the following:

Add a #4 cable from the firewall ground point to the rearmost bolt of the fuel injection rail.
Add a #4 cable from the dipstick tube stud over to the passenger side inner fender. There is an 8mm stud almost directly below theupper shock mounting point.
Add a #6 cable from the negative battery terminal to one of the 10mm headed bolts on the radiator support.
Be sure to clean all connections to bare metal in the process.
cruiser54 is online now   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Okay. I'm gonna try looking for answers here one last time before I head to a shop. Zerocyde OEM XJ Cherokee Technical. All XJ Non-modified/stock questions go here 24 06-03-2017 02:10 PM
Auto Meter coolant temp sensor electrical hookup Team SAW MODIFIED XJ Cherokee Tech 1 09-11-2015 08:26 AM
1988 Jeep Cherokee back firing dock2778 OEM XJ Cherokee Technical. All XJ Non-modified/stock questions go here 3 09-08-2015 07:04 PM
99 XJ A/C blower intermittently working shotseven OEM XJ Cherokee Technical. All XJ Non-modified/stock questions go here 0 09-06-2015 03:06 PM
Hello from Louisiana! 4doorXJ Introductions 0 09-04-2015 07:33 PM



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -5. The time now is 07:22 AM.


 
  • Ask a Question
    Get answers from community experts
Question Title:
Description: