1996 sport rpm gauge is off about 200-300 rpms - JeepForum.com

 
LinkBack Thread Tools
post #1 of 6 Old 08-13-2013, 09:46 AM Thread Starter
oldschool88
Registered User
1996 XJ Cherokee 
 
Join Date: Nov 2012
Location: cadillac
Posts: 41
1996 sport rpm gauge is off about 200-300 rpms

1996 cherokee sport.. rpm gauge is low.. sometimes way to low.. around 1500 rpms when it should be around 2000.. i notice it while accelerating.. at idle it always reads around 750.. my 1992 laredo did the same thing before i sold it.. from what i understand the rpm readings come from the pcm.. how can i fix this ?

oldschool88 is offline  
Sponsored Links
Advertisement
 
post #2 of 6 Old 08-13-2013, 10:46 AM
bigbill888
Registered User
1996 ZJ 
 
Join Date: Nov 2009
Location: michigan
Posts: 969
Did you hook up another tachometer to it? How do you know its reading low?

96 ZJ Laredo, 4.0, 242, 230K
95 ZJ Limited, 4.0, 242, 140K
98 XJ Sport, 4.0, 231, 140K
All work well
bigbill888 is offline  
post #3 of 6 Old 08-13-2013, 11:07 AM
CJ7-Tim
Real Jeeps have dents
 
CJ7-Tim's Avatar
2000 XJ Cherokee 
 
Join Date: Apr 2002
Location: out in the garage - Minneapolis
Posts: 24,665
It might bug you, but it isn't a problem worth the time or effort to fix.

.

A recent Gallup public opinion poll shows the NRA, at 58% approval, has a higher approval rating than either Hillary Clinton or Barack Obama.

Progressive Liberalism: Bringing you new Healthcare ideas so wonderful, they have to include mandatory participation ...

Originally Posted by Ronald W. Reagan: Government is not the solution to our problems; Government is the problem.
CJ7-Tim is offline  
post #4 of 6 Old 08-13-2013, 11:08 AM Thread Starter
oldschool88
Registered User
1996 XJ Cherokee 
 
Join Date: Nov 2012
Location: cadillac
Posts: 41
no i didn't hook up another tach to it. sometimes it reads normal, acceleration patterns and shift patterns are the same.. then it will all of a sudden read 1500 rpms while im accelerating instead off the usual 2000 rpms. its kinda hard to explain.. but i know the rpm gauge is off.. when im accelerating i ushally am around 2000-2200 rpms.. when the rpm gauge is acting up its around 1500rpms, with the same amount of throttle. sorry for any confusion, im trying to explain it best i can..
oldschool88 is offline  
post #5 of 6 Old 08-15-2013, 06:59 AM
JWELK
Registered User
1999 XJ Cherokee 
 
Join Date: Apr 2011
Location: Ceiba
Posts: 910
I have a 99, the tach seems to be a combination of the Crankshaft Position and Cam Shaft Position sensor inputs. It seems they go to a counter circuit in the PCM and the resulting digital output is sent to the tach. It is similar on my 95 Wrangler. However the gauge is different. There is uprocessor in the gauge that counts the pulses and then adjusts an electromagnet in the gauge to give the proper reading. As you don't mention other issues, I would venture the tach gauge is the culprit. Again that is for a 95, I don't know about the '96.

Let us know,

Regards,

Jim W
JWELK is offline  
post #6 of 6 Old 08-15-2013, 08:38 AM Thread Starter
oldschool88
Registered User
1996 XJ Cherokee 
 
Join Date: Nov 2012
Location: cadillac
Posts: 41
Thanks for the info , greatly appreciated... I will dive deeper into it once I get some time.. I will update this post when I figure it out.. Thanks again.
oldschool88 is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the JeepForum.com forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid e-mail address for yourself.



Email Address:
OR

Log-in









Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Posting Rules  
You may post new threads
You may 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 On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome