Home 
Home Search search Menu menu Not logged in - Login | Register

 Moderated by: Greg Fletcher
New Topic Reply Printer Friendly
trouble shooting my tach  Rating:  Rating
AuthorPost
 Posted: 01-18-2013 08:06 pm
  PM Quote Reply
1st Post
JHDSL
Guest
 

Joined: 
Location:  
Posts: 
Status: 
Offline
Anyone have any thoughts on what to do to trouble shoot my tach. i have a 1974 JH and the tach looks original. Its dead all the timeother than a recent highway drive when it came alive for a few minutes, stuck at 4000 and then died. Where to look in the engin bay for wires and termination point? and  - Would anyone know the red line speeds for 1st, 2nd and 3rd gears? Thanks

Back To Top PM Quote Reply  

 Posted: 01-19-2013 12:57 am
  PM Quote Reply
2nd Post
Jensen Healey
Super Moderator


Joined: 03-11-2005
Location: San Anselmo, California USA
Posts: 983
Status: 
Offline
Welcome to the forum!

Please post your vin number and, if you can see it above the starter, engine number to the VIN database. The Jensen historian Ric Calver keeps track of running cars, junked cars, and all things Jensen.

The current for the ignition flows through the tach and the tach "reads" the electromagnetic field around the wire.

If the car is running, we can assume the problem is in the tach itself.

The speed per 1000 rpm are listed in the repair manual. do you have a 4 speed or 5 speed transmission?

Cheers, Kurt

Back To Top PM Quote Reply

 Posted: 01-21-2013 10:42 pm
  PM Quote Reply
3rd Post
JHDSL
Guest
 

Joined: 
Location:  
Posts: 
Status: 
Offline
I emailed richard and he has my vin number, and I'm looking for teh engin number. An update on the tach. I was on drive yesterday and late in the run it starts working, not working very well but working. Is there anything else I could check? Are there moving parts inside that i could clean or lubricate? thanks

Back To Top PM Quote Reply  

 Posted: 01-23-2013 05:30 am
  PM Quote Reply
4th Post
answerman
Member
 

Joined: 09-10-2012
Location: Little Chute, Wisconsin USA
Posts: 435
Status: 
Offline
Mine hasn't worked since I got it, doesn't move at all. Curious to see what you come up with. I've established that it's not the wiring or ignition in my case.

Back To Top PM Quote Reply

 Posted: 01-23-2013 12:16 pm
  PM Quote Reply
5th Post
JHDSL
Guest
 

Joined: 
Location:  
Posts: 
Status: 
Offline
I believe it's the tach itself. I guess thenonlynway to test this is to buy a replacement. Not suremim there yet. I will keep this post going.

Back To Top PM Quote Reply  

 Posted: 01-24-2013 07:13 pm
  PM Quote Reply
6th Post
dwalls1
Member
 

Joined: 04-11-2008
Location: Bloomfield, New Mexico USA
Posts: 207
Status: 
Offline
MOMA in Alburquerque, NM can fix it for you. They can also modify it to work with the Pertronics ignition. I am sorry I do not have their contact information at hand, but it should be readily available in this modern age.

Back To Top PM Quote Reply

 Posted: 01-24-2013 08:49 pm
  PM Quote Reply
7th Post
JHDSL
Guest
 

Joined: 
Location:  
Posts: 
Status: 
Offline
Mo Ma Manufacturing - instrument repair
13211 Second Street. NW
Albuquerque, NM 87102
Ph (505) 766-6661 - Fax (505) 766-5419
momanm@aol.com

Thank you - I will give them a call. Does anyone have any tips for removing the tach?

Back To Top PM Quote Reply  

 Posted: 01-24-2013 10:34 pm
  PM Quote Reply
8th Post
Frank Schwartz
Member
 

Joined: 02-18-2011
Location:  
Posts: 313
Status: 
Offline
I have a couple of Tachs from Junked JHs...they all look the same to me...and if you are using the standard ignition and not Pertronics or something else, they should work just fine. So if anyone wants one, please contact me off this site...at mfsjr2@comcast.net
Frank Schwartz

Back To Top PM Quote Reply

 Posted: 01-25-2013 09:35 pm
  PM Quote Reply
9th Post
answerman
Member
 

Joined: 09-10-2012
Location: Little Chute, Wisconsin USA
Posts: 435
Status: 
Offline
JHDSL wrote:Does anyone have any tips for removing the tach?It's actually pretty easy... assume the Lotus position with your head shoved under the dash, remove 3 wires (I believe) and then remove the two thumbscrews that pull it back against the back of the dash.  Comes right out the face of the dash then.

Back To Top PM Quote Reply  

 Posted: 01-25-2013 11:06 pm
  PM Quote Reply
10th Post
JHDSL
Guest
 

Joined: 
Location:  
Posts: 
Status: 
Offline
Thanks - I see there are two screws on the face od the dash. Do these come out, the dash face comes of and then its as you explained?

Back To Top PM Quote Reply

 Posted: 01-26-2013 07:58 pm
  PM Quote Reply
11th Post
Gary Martin JH 15371
Member
 

Joined: 03-12-2005
Location: Portland, OR
Posts: 98
Status: 
Offline
The dash cluster (or binacle as the Brits call it) with all four gauges will come out, but it can be difficult if it has not been out recently. On the back of the cluster in the center there is a metal rod that slides within a clip to hold the cluster. After years it gets rusty and prevents cluster from coming out easily. If you can clean and lube the rod from under the dash first it will make it a lot easier. The only other things to remove first are the two screws you see from the front, and the speedo cable. It might just be easier to remove the tach and not the whole cluster.

My car has the Pertronix. The tach works most of the time, but it jumps around a lot. I think I need to get it modified. Thanks for the info on MoMa Instrument Shop. Anyone know of a similar shop up here in the Pacific NW ?

Gary  

Back To Top PM Quote Reply  

 Posted: 01-28-2013 05:46 pm
  PM Quote Reply
12th Post
answerman
Member
 

Joined: 09-10-2012
Location: Little Chute, Wisconsin USA
Posts: 435
Status: 
Offline
JHDSL wrote: Thanks - I see there are two screws on the face od the dash. Do these come out, the dash face comes of and then its as you explained?I don't think we are talking about the same thing.   The tach is mounted in a hole in the dash.  If you disconnect the wiring, and look at it from the back/underneath, you will see two knurled nuts that hold clamps that pull the tach back into the face of the dash.  If you remove those, from behind you can push the tach right through the hole (toward the steering wheel).  It pops right out.  You don't need to remove anything else.

Back To Top PM Quote Reply

 Posted: 01-28-2013 08:08 pm
  PM Quote Reply
13th Post
JHDSL
Guest
 

Joined: 
Location:  
Posts: 
Status: 
Offline
OK - this makes more sense. Thanks for the clarification. I hope I can fit/contort myself under the dash :)

Back To Top PM Quote Reply  

 Posted: 01-29-2013 02:44 am
  PM Quote Reply
14th Post
Mike Aubuchon
Member
 

Joined: 03-13-2005
Location: Surprise, Arizona USA
Posts: 20
Status: 
Offline
I found it easier to remove the drivers seat. With the seat out you can lay on your back and reach under the dash. Still a tight squeeze but at least you can see what you are doing. There is a lot of wiring in a small area behind the dash so be careful not to disturb the other circuits.

Mike

Back To Top PM Quote Reply

Current time is 12:37 pm  
> Jensen Healey & Jensen GT Tech > Electrical & Instruments > trouble shooting my tach Top




UltraBB 1.172 Copyright © 2007-2011 Data 1 Systems