General Technical & Electrical General technical and electrical discussion for the Ford Ranger that does not fit in any other sub-forum.

Tachometer is way off.

Thread Tools
 
Search this Thread
 
Old May 25, 2011
  #1  
sheltonfilms's Avatar
Thread Starter
|
Member
Joined: Apr 2010
Posts: 645
Likes: 2
From: Knoxville, TN
Tachometer is way off.

So I installed some Explorer Sport gauges a long long time ago (like 6 or 7 years ago) and the tach worked perfect. Idle was right on and so was redline. But just recently the the tach is showing idle around 400 RPMs and Redline is around 4000 something.

Just recently I changed out my GEM and wiring harnesses from another ranger with power doors. But I looked at my wiring manual and it showed that the tach signal is coming straight from the PCM. So what could be the problem?
 
Reply
Old May 25, 2011
  #2  
V8 Level II's Avatar
RF Veteran
iTrader: (4)
Joined: Nov 2004
Posts: 7,910
Likes: 27
From: Michigan
Correct. The tach pulse comes directly from the PCM.

However, the ground wires present in the cluster connector of the dash harness determine if the Ranger/Explorer tach is calibrated for a 4, 6 or 8 cylinder engine. If you swapped a V6 dash harness into your 4-cylinder truck, the tach will read 2/3 of actual RPM because of the lower number of pulses/revolution.

Originally Posted by rwenzing

96~2003 Ranger tachometer wiring for 4, 6 or 8 cylinders:

8-cylinder: "Selector" ground configuration:
  • pin 8 of the 10-pin: (NOT connected to anything)
  • pin 16 of the 16-pin: (wired to chassis ground)

6-cylinder: "Selector" ground configuration:
  • pin 8 of the 10-pin: (wired to chassis ground)
  • pin 16 of the 16-pin: (NOT connected to anything)

4-cylinder: There is no "Selector" ground
  • pin 8 of the 10-pin: (NOT connected to anything)
  • pin 16 of the 16-pin: (NOT connected to anything)
So, assuming that you have a V6 dash harness transplanted into your 2000 2.5 truck, you'd need to disconnect the black/yellow ground from pin 8 of C216.
 
Reply
Old May 25, 2011
  #3  
sheltonfilms's Avatar
Thread Starter
|
Member
Joined: Apr 2010
Posts: 645
Likes: 2
From: Knoxville, TN
Brilliant answer! I just noticed that little box next to the ground wire that reads "3.0 and 4.0", and it was a V6 donor harness. I take it you had to mod yours for your V8 conversion.
 
Reply
Old May 26, 2011
  #4  
95lorange's Avatar
Member
Joined: Mar 2009
Posts: 54
Likes: 0
From: Hurt, VA
Don't mean to hijack, but yes I do. What about for a 95? I can't find much info on that.
 
Reply
Old May 26, 2011
  #5  
V8 Level II's Avatar
RF Veteran
iTrader: (4)
Joined: Nov 2004
Posts: 7,910
Likes: 27
From: Michigan
Originally Posted by sheltonfilms
I take it you had to mod yours for your V8 conversion.
Yes, recalibration is as simple as releasing the 'V6' ground pin from one of the cluster connectors and moving it to the new 'V8' position in another connector.
 
Reply
Old May 26, 2011
  #6  
V8 Level II's Avatar
RF Veteran
iTrader: (4)
Joined: Nov 2004
Posts: 7,910
Likes: 27
From: Michigan
Originally Posted by 95lorange
Don't mean to hijack, but yes I do. What about for a 95? I can't find much info on that.
Compared to the years before and after, 1995 uses a unique cluster and a unique harness pinout and it is not clear in the 95 EVTM how the tach difference between 4 cylinder and 6 cylinder trucks is accommodated.

Based on what was done in 94 and 96, here's my best GUESS for 1995. A black/yellow wire to ground from pin #1 of the 14-pin calibrates the tach for a 6-cylinder; no ground from pin #1 of the 16-pin sets the tach up for a 4-cylinder. Remember, this is an unproven guess, nothing more.
 
Reply
Old Aug 24, 2011
  #7  
mojeeper's Avatar
Member
Joined: Aug 2011
Posts: 17
Likes: 0
From: St Joe Mo
OK so if I understand this its just plug and play to put in an instrument panel with a tach in my 2000 with 2.5 in it ranger?
 
Reply
Old Aug 24, 2011
  #8  
sheltonfilms's Avatar
Thread Starter
|
Member
Joined: Apr 2010
Posts: 645
Likes: 2
From: Knoxville, TN
Originally Posted by mojeeper
OK so if I understand this its just plug and play to put in an instrument panel with a tach in my 2000 with 2.5 in it ranger?
Yeah that is correct. I put in an Explorer Sport white faced cluster in mine and it was plug and play. Probably the easiest mod I've ever done.

My problem was with swapping out a wiring harness.
 
Reply
Old Aug 24, 2011
  #9  
StxDangerRanger's Avatar
RF Veteran
iTrader: (2)
Joined: Dec 2010
Posts: 6,315
Likes: 8
From: Michigan
Originally Posted by rwenzing
Compared to the years before and after, 1995 uses a unique cluster and a unique harness pinout and it is not clear in the 95 EVTM how the tach difference between 4 cylinder and 6 cylinder trucks is accommodated.

Based on what was done in 94 and 96, here's my best GUESS for 1995. A black/yellow wire to ground from pin #1 of the 14-pin calibrates the tach for a 6-cylinder; no ground from pin #1 of the 16-pin sets the tach up for a 4-cylinder. Remember, this is an unproven guess, nothing more.
Wasn't 95 the year they changed the dash over and went to OBD2?
wouldn't that make it the same? as what you said above?
 
Reply
Old Aug 25, 2011
  #10  
V8 Level II's Avatar
RF Veteran
iTrader: (4)
Joined: Nov 2004
Posts: 7,910
Likes: 27
From: Michigan
Originally Posted by StxDangerRanger
Originally Posted by rwenzing
Compared to the years before and after, 1995 uses a unique cluster and a unique harness pinout and it is not clear in the 95 EVTM how the tach difference between 4 cylinder and 6 cylinder trucks is accommodated.

Based on what was done in 94 and 96, here's my best GUESS for 1995. A black/yellow wire to ground from pin #1 of the 14-pin calibrates the tach for a 6-cylinder; no ground from pin #1 of the 16-pin sets the tach up for a 4-cylinder. Remember, this is an unproven guess, nothing more.
Wasn't 95 the year they changed the dash over and went to OBD2?
Yes



Originally Posted by StxDangerRanger
wouldn't that make it the same? as what you said above?
No.

The 1995 cluster appears outwardly identical to the 96~2003 style clusters but there are differences in the 95 cluster itself and its connector pinouts.
 
Reply
Old Aug 25, 2011
  #11  
mojeeper's Avatar
Member
Joined: Aug 2011
Posts: 17
Likes: 0
From: St Joe Mo
Thanks for the reply Anthony thats what I plan on doing to mine
 
Reply
Old Sep 20, 2011
  #12  
mojeeper's Avatar
Member
Joined: Aug 2011
Posts: 17
Likes: 0
From: St Joe Mo
Originally Posted by sheltonfilms
Yeah that is correct. I put in an Explorer Sport white faced cluster in mine and it was plug and play. Probably the easiest mod I've ever done.

My problem was with swapping out a wiring harness.
OK now that I have the 02 explorer sport cluster in my 2000 ranger every thing works but the check engine light is this common on this swap?
 
Reply
Old Sep 20, 2011
  #13  
sheltonfilms's Avatar
Thread Starter
|
Member
Joined: Apr 2010
Posts: 645
Likes: 2
From: Knoxville, TN
By saying that the light doesn't work do you mean that its on?

Have your codes read if it is.
 
Reply
Old Sep 20, 2011
  #14  
mojeeper's Avatar
Member
Joined: Aug 2011
Posts: 17
Likes: 0
From: St Joe Mo
Originally Posted by sheltonfilms
By saying that the light doesn't work do you mean that its on?

Have your codes read if it is.
no it doesn't light at all and i'm sure that the bulb is good
 
Reply
Old Sep 20, 2011
  #15  
sheltonfilms's Avatar
Thread Starter
|
Member
Joined: Apr 2010
Posts: 645
Likes: 2
From: Knoxville, TN
Did your check engine light come on before the swap?

Does it not come one when you first turn your ignition on?
 
Reply
Old Sep 20, 2011
  #16  
mojeeper's Avatar
Member
Joined: Aug 2011
Posts: 17
Likes: 0
From: St Joe Mo
[QUOTE=sheltonfilms;1894329]Did your check engine light come on before the swap?

Does it not come one when you first turn your ignition on?[/QUOTE

yes Im sure it came on before the swap and no it dont come on when you first turn on the ignition
 
Reply
Old Sep 20, 2011
  #17  
sheltonfilms's Avatar
Thread Starter
|
Member
Joined: Apr 2010
Posts: 645
Likes: 2
From: Knoxville, TN
Ok looks like the is a pinning difference. Let me double check all the wires for both models and see if others are switched too.

Edit: For some reason I was looking at a 95 Ranger diagrams (got confused with above posts)
 

Last edited by sheltonfilms; Sep 20, 2011 at 04:04 PM.
Reply
Old Sep 20, 2011
  #18  
sheltonfilms's Avatar
Thread Starter
|
Member
Joined: Apr 2010
Posts: 645
Likes: 2
From: Knoxville, TN
Pins on 2000 2.5 and 2002 sport look identical. Check engine light pin is the same. I would say you have a bad bulb.
 
Reply
Old Sep 20, 2011
  #19  
mojeeper's Avatar
Member
Joined: Aug 2011
Posts: 17
Likes: 0
From: St Joe Mo
Originally Posted by sheltonfilms
Pins on 2000 2.5 and 2002 sport look identical. Check engine light pin is the same. I would say you have a bad bulb.
Ill pop it out and change it and see what that does thanks for the help
Brent
 
Reply
Old Sep 21, 2011
  #20  
mojeeper's Avatar
Member
Joined: Aug 2011
Posts: 17
Likes: 0
From: St Joe Mo
Originally Posted by mojeeper
Ill pop it out and change it and see what that does thanks for the help
Brent
well three different bulbs and sockets later I now have a check engine light
Thanks for all the help Anthony
 
Reply
Old Jul 1, 2019
  #21  
Hbrector's Avatar
Member
Joined: Oct 2016
Posts: 14
Likes: 1
From: Key West, FL
Tach starts at 3400rpm

I'm sorry, I have not done any modifications to my truck. Over the past 6 months my Tach would sometimes jump to 3400rpm and then drop back to accurate RPM's (2000). Now it has stuck at the jump spot (3300-3400rpm). Does anyone REALLY know what causes this?

Thank you, BR
 
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
arownious
8-Cylinder Tech
36
Oct 17, 2024 03:43 PM
Bob G
General Technical & Electrical
4
Oct 8, 2008 04:42 PM
LayingFrame89
General Technical & Electrical
4
Jan 18, 2008 07:10 PM
AgPete139
General Ford Ranger Discussion
3
Nov 26, 2007 04:56 AM
Needforspeed3685
General Technical & Electrical
5
Aug 11, 2007 10:25 AM




All times are GMT -6. The time now is 08:08 AM.