Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help




Go Back   PeachParts Mercedes-Benz Forum > Mercedes-Benz Tech Information and Support > Diesel Discussion

Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 12-22-2018, 01:32 PM
Registered User
 
Join Date: Dec 2018
Posts: 111
Tach install

Looking at one of these, I have a 300TD swap, the sensor lead from the pickup on the crank shaft ( front of engine, see Pic) is still on the engine.. Just wondering if I could use that sensor/pickup for this tach??

Sent from my SM-G892A using Tapatalk
__________________
Brad

Bunch of old metal, trying to keep it on the road....
Reply With Quote
  #2  
Old 12-23-2018, 11:36 AM
cornemuse's Avatar
red herring
 
Join Date: Sep 2012
Location: Geographly, heaven. Politically, hell.
Posts: 746
Should work, they're just simple wire coil sensors (sense disruption in magnetic field at the groove in that pulley/harmonic balancer, what ever it is)
__________________
"I applaud your elaborate system of denial"
Reply With Quote
  #3  
Old 12-23-2018, 12:45 PM
Registered User
 
Join Date: Dec 2018
Posts: 111
That's what I was hoping....

Sent from my SM-G892A using Tapatalk
__________________
Brad

Bunch of old metal, trying to keep it on the road....
Reply With Quote
  #4  
Old 12-23-2018, 01:49 PM
jay_bob's Avatar
Control Freak
 
Join Date: Oct 2011
Location: Columbia, SC
Posts: 3,273
Or find a tach/clock instrument from a diesel 123 and switch it out for the clock part of your cluster. Gas tach won’t work on a diesel because it counts the sparks.
__________________
2014 ML350 Bluetec (wife's DD)
2008 E320 Bluetec (my DD)
2008 ML320 CDI (Older son's college DD)
1998 E300DT (Younger son's college DD)
1987 300TD sold to vstech
----------
gone but living on
1983 240D (body to greazzer, engine to t walgamuth)
Reply With Quote
  #5  
Old 12-23-2018, 01:54 PM
Registered User
 
Join Date: Dec 2018
Posts: 111
Quote:
Originally Posted by jay_bob View Post
Or find a tach/clock instrument from a diesel 123 and switch it out for the clock part of your cluster. Gas tach wonít work on a diesel because it counts the sparks.
Looked into that, have to have the tach Amp and the wiring harness, my 240d didn't have one from the factory so no wiring harness...

Sent from my SM-G892A using Tapatalk
__________________
Brad

Bunch of old metal, trying to keep it on the road....
Reply With Quote
  #6  
Old 12-23-2018, 07:07 PM
Registered User
 
Join Date: Dec 2018
Posts: 111
Quote:
Originally Posted by jay_bob View Post
Or find a tach/clock instrument from a diesel 123 and switch it out for the clock part of your cluster. Gas tach wonít work on a diesel because it counts the sparks.
I've found an 83 300Td, has the gauge cluster and the Amp on the inner fender and all wiring, question is what wiring do I need, I have the pickup and wire on my engine now that is attached to the front crank pulley, but that's it (see pics) what would I need off the 83??

Sent from my SM-G892A using Tapatalk
__________________
Brad

Bunch of old metal, trying to keep it on the road....
Reply With Quote
  #7  
Old 01-06-2019, 11:54 AM
Registered User
 
Join Date: Dec 2018
Posts: 111
After doing more research, the 85 300Td I have in this 81 240D would get its tach signal from the speed sensor reading from the flywheel, I believe the sensor is still there.. But.. The signal goes through an EGR computer first (which I don't have on the 240) then to the gauge, don't know if not having this and trying to do a "direct wire" from the sensor to the gauge would work.. Found a video that the guy did just jumper the leads of the EGR computer plug in to get his to work, so I'm assuming that would be the same as a direct wire.... Anybody got any input on this??? I'd like to keep it stock looking but hate to fork out the $$for a gauge cluster just to find out it won't work....

Sent from my SM-G892A using Tapatalk
__________________
Brad

Bunch of old metal, trying to keep it on the road....
Reply With Quote
  #8  
Old 01-06-2019, 12:48 PM
ykobayashi's Avatar
Registered User
 
Join Date: Jun 2005
Location: Irvine, CA
Posts: 559
Heads up that the 85 is an entirely different animal than the other 80’s turbos.

The tach amp is behind the 85 glove box with a 10a blade fuse on top.

You can probably use the 83 turbos amp and the 240 pickup but you have to do your own wiring for 12v, god, signal low, & amplified signal. Sounds like you already know this.

Images of amp in post 31 of my 85 thread.
Got a 1985 300D turbo

Edit - ugh like usual I spoke too soon. The little silver box under the fuse may not be the tach amp. The fuse supplies power to the tach amp electronics which is likely in the EGR controller that you do not have. I’ve been searching around and I cannot find the thread about redesigning the tach amp. They had pinouts and schematics for the 83 version which can help you with your rewire job.

Here is the schematic. A little fuzzy but it has all the pinout numbers for the wiring.
How the Tach Amp works
__________________
ykobayashi
82 240D stick shift 335k miles (SOLD)
82 300SD 200k miles
85 300D Turbodiesel 160k miles

Last edited by ykobayashi; 01-06-2019 at 01:08 PM.
Reply With Quote
  #9  
Old 01-06-2019, 02:08 PM
Registered User
 
Join Date: Dec 2018
Posts: 111
Quote:
Originally Posted by ykobayashi View Post
Heads up that the 85 is an entirely different animal than the other 80ís turbos.

The tach amp is behind the 85 glove box with a 10a blade fuse on top.

You can probably use the 83 turbos amp and the 240 pickup but you have to do your own wiring for 12v, god, signal low, & amplified signal. Sounds like you already know this.

Images of amp in post 31 of my 85 thread.
Got a 1985 300D turbo

Edit - ugh like usual I spoke too soon. The little silver box under the fuse may not be the tach amp. The fuse supplies power to the tach amp electronics which is likely in the EGR controller that you do not have. Iíve been searching around and I cannot find the thread about redesigning the tach amp. They had pinouts and schematics for the 83 version which can help you with your rewire job.

Here is the schematic. A little fuzzy but it has all the pinout numbers for the wiring.
How the Tach Amp works
I'll go through this also, I just have the 85 engine, everything else is the 81 240D...so I have nada on the wiring side for this... That's why I was hoping if I took everything out of the 83 300d parts car I would have what I needed... Thank you for the diagrams.. I'm out messing with it now, I don't have a sensor lead coming off the flywheel area that I can find anyway...

Sent from my SM-G892A using Tapatalk
__________________
Brad

Bunch of old metal, trying to keep it on the road....
Reply With Quote
  #10  
Old 01-07-2019, 12:19 AM
ykobayashi's Avatar
Registered User
 
Join Date: Jun 2005
Location: Irvine, CA
Posts: 559
Quote:
Originally Posted by BATComm1966 View Post
I don't have a sensor lead coming off the flywheel area that I can find anyway...

Sent from my SM-G892A using Tapatalk
You know whatís funny, I went through the same thing on my 1982 240d and I recall there was some kind of pickup there. It was funny because the car didnít have a tach...just a big nice clock. But I recall there was something down there. Maybe it was a stud on the balancer? Memory failing me. I feel like there was a cable with a diagnostic plug at the firewall...but I may be mixing up my cars.

Good luck. Probably best to pull everything you can from the 83 300d for the transplant.
__________________
ykobayashi
82 240D stick shift 335k miles (SOLD)
82 300SD 200k miles
85 300D Turbodiesel 160k miles
Reply With Quote
  #11  
Old 01-07-2019, 12:49 AM
Registered User
 
Join Date: Dec 2018
Posts: 111
Quote:
Originally Posted by ykobayashi View Post
You know whatís funny, I went through the same thing on my 1982 240d and I recall there was some kind of pickup there. It was funny because the car didnít have a tach...just a big nice clock. But I recall there was something down there. Maybe it was a stud on the balancer? Memory failing me. I feel like there was a cable with a diagnostic plug at the firewall...but I may be mixing up my cars.



Good luck. Probably best to pull everything you can from the 83 300d for the transplant.
Yup... Mine has the pickup on the crank pulley also... But I'm thinking the same, grab everything off the 83 and it "should" bolt on and work...

Sent from my SM-G892A using Tapatalk
__________________
Brad

Bunch of old metal, trying to keep it on the road....
Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

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 On
Trackbacks are On
Pingbacks are On
Refbacks are On




All times are GMT -4. The time now is 05:06 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2018 Pelican Parts, LLC - Posts may be archived for display on the Peach Parts or Pelican Parts Website -    DMCA Registered Agent Contact Page