+- STD (https://www.superturbodiesel.com/std)
+-- Forum: Tuning (https://www.superturbodiesel.com/std/forumdisplay.php?fid=6)
+--- Forum: Engine (https://www.superturbodiesel.com/std/forumdisplay.php?fid=7)
+--- Thread: Adding a tachometer (/showthread.php?tid=97)
Pages:
1
2
Adding a tachometer - ForcedInduction - 06-18-2008
Adding a tach to a car without one or with an 84-85 setup is very easy. You can get all the parts new or used, but the junkyard is best since you need several inches of the wiring harness.
Parts needed:
Tachometer with two prong plug, three will not work, and a few inches of the pigtail.
Pickup sensor, all OM61x engines have the bracket in place to mount it.
Base/amp bracket, all W123 models have predrilled holes to mount the bracket on the drivers side fender by the glowplug relay.
Amp base and a few inches of it's pigtail.
Tach amp.
16' of ~24 gauge wire.
Misc electrical butt connectors, tape.
Wiring:
Plug white pickup sensor into it's base socket.
The pigtail of the amp base will have 3 wires- Brown, green, black.
Brown is ground, attach it to any clean ground connection in the engine bay.
Black is power for the amp and tachometer. Connect it to a switched power source (there is one in the glow relay) with an inline 3amp fuse, run that wire from the amp base to the black/red stripe wire on the tach pigtail to power both the amp and tach.
Green is RPM signal output. Run that wire to the green/stripe wire of the tachometer pigtail.
Start the engine and enjoy.
Re: Adding a tachometer - ForcedInduction - 06-18-2008
techguy512 of the Mercedesshop.com forums has built a modern replacement for the old tach amplifier.
He is asking $46 each. The thread and his contact information can be found here:
http://www.mercedesshop.com/shopforum/showthread.php?t=219949
Re: Adding a tachometer - winmutt - 06-18-2008
Here is a writeup on a DIY digital one:
DIY - Microcontroller based digital tachometer
RE: Adding a tachometer - Gasoline Fumes - 02-15-2009
Why wouldn't a 3-prong work? I'm hoping to swap my 617.952 into a manual 240. It looks like my tachometer from the 300D is a 3-prong.
RE: Adding a tachometer - ForcedInduction - 02-15-2009
(02-15-2009, 10:01 AM)Gasoline Fumes Why wouldn't a 3-prong work?
I don't know what each pin is wired for. The two pin is simple: power-signal.
RE: Adding a tachometer - Gasoline Fumes - 02-15-2009
(02-15-2009, 11:26 PM)ForcedInduction(02-15-2009, 10:01 AM)Gasoline Fumes Why wouldn't a 3-prong work?
I don't know what each pin is wired for. The two pin is simple: power-signal.
They're labeled on the back of my cluster:
W
-G
+
I think I can figure it out.
RE: Adding a tachometer - ForcedInduction - 02-15-2009
(02-15-2009, 11:41 PM)Gasoline Fumes They're labeled on the back of my cluster:
W
-G
+
I think I can figure it out.
Ah, thats good. The three-pin one I have isn't labeled.
RE: Adding a tachometer - winmutt - 02-16-2009
Whats W?
RE: Adding a tachometer - Gasoline Fumes - 02-17-2009
(02-16-2009, 09:51 PM)winmutt Whats W?
I'm pretty sure that's the signal.
I looked at the harness in my '85 300D and the -G pin is not used, only two wires there.
RE: Adding a tachometer - winmutt - 02-17-2009
85 has two pick ups, one on the balancer for testing and the other on the bellhousing/flywheel.
RE: Adding a tachometer - ForcedInduction - 02-17-2009
The EGR computer drives it, the same way it works on the 240D.
RE: Adding a tachometer - Gasoline Fumes - 02-17-2009
So to use the '85 tach in an '83 240D, I need the EGR computer, or the tach amp, or both? Is there a good wiring diagram out there for the '85 300D? I have the Haynes manual, but I'd never call it good.
OK, I just read the thread on Mercedesshop.com and I see I don't have the amp. The tach amp he's selling is tempting, but I'll probably just use the EGR computer to drive it. That's behind the little door in the kick panel, right?
RE: Adding a tachometer - BRABUS - 06-15-2010
hello
Im not so good in english.
What is Amp base and Tach amp.
Is sensor reading from the crank shaft wheel?
Is it still possible to get the modern replacement for the old tach amplifier ?
Thanks for helping me.
Best regards
RE: Adding a tachometer - charmalu - 06-15-2010
(06-15-2010, 06:42 PM)BRABUS hello
Im not so good in english.
What is Amp base and Tach amp.
Is sensor reading from the crank shaft wheel?
Is it still possible to get the modern replacement for the old tach amplifier ?
Thanks for helping me.
Best regards
The link in post #2 doesn`t work, mercedesshop is now peachparts.
here is the new link...OM617A tach Amp
http://www.peachparts.com/shopforum/showthread.php?t=219949
this link is... How the tach amp works
http://www.peachparts.com/shopforum/showthread.php?t=206808
read through this might get you up to speed.
Charlie
RE: Adding a tachometer - Syncro_G - 06-16-2010
those are posts for Bob Myers' custom tach amp.
here's his official site:
http://www.mbelectronicupgrades.com/
I worked with him to make a tach amp that can work with more aftermarket or gasser tachs - thus opening more options.
for example, he made me a tach amp that could drive my stock M110 tach that was designed to receive a 12V pulse from a coil 3 times per revolution.
he also has upgraded programmable wiper relays that are really awesome when driving in variable rain conditions.
RE: Adding a tachometer - ForcedInduction - 06-16-2010
The versatility is the beauty of using modern computing to do something so simple. He can also program it to send a voltage signal at a desired RPM range to trigger a high boost stage, water injection, nitrous, etc. Memory is limited though, so some more complicated things might mean he has to delete the "self test" startup sweep feature to make room.
RE: Adding a tachometer - Captain America - 06-16-2010
DOPE!!!!
RE: Adding a tachometer - SixSpeed - 06-17-2010
Hey Guys, question.
I am in-process of wiring up my Unimog. I have a VDO programmable tach I am going to use with my 617's crank sensor. I also am planning on using the electronic amp from MBelectronicUpgrades.com
Anyways, In order to calibrate the VDO tach....I need to know what my idle RPM is. Anyones guess on the easiest way? Use a 300DT tach?
RE: Adding a tachometer - ForcedInduction - 06-18-2010
Optical tachometer.
http://www.harborfreight.com/digital-photo-sensor-tachometer-66632.html
RE: Adding a tachometer - GREASY_BEAST - 06-19-2010
No electronic speedometer yet?
RE: Adding a tachometer - JB3 - 06-26-2010
Ok, so after reading through this thread, and techguys thread, Im still not completely sure how the tach works on some of these cars without an amp.
I want to put a tach in my 80 240, which had none, so I went to the yard this morning and unfortunately could not find a single 123 with an instrument cluster left.
Instead, I grabbed the instrument cluster out of an 82 300SD, the tach base, pickup, and now I don't understand how this worked. Wires from the pickup come over to the base, and wires leave the base, theres no amp, but the wires aren't connected in some way ????? Did the tachs on SDs with a 617 work differently?
Do I need to grab some more parts, like the EGR computer? will I be able to make this work in my 240?
here are some pics
[attachment=3005]
RE: Adding a tachometer - ForcedInduction - 06-26-2010
That wasn't an 82 SD. The 300SD was only offered with SRS in 85, which has an EGR computer that drives the tachometer.
The base you grabbed is for 84/85 and g@s engine models and is just a diagnostic plug for a mechanic to check engine RPM. The parts you have, except the tachometer, will work for your car but you'll need to get an amplifier from an 82-84 model. The W126 tach will not physically fit in a W123.
RE: Adding a tachometer - JB3 - 06-26-2010
(06-26-2010, 10:53 AM)ForcedInduction That wasn't an 82 SD. The 300SD was only offered with SRS in 85, which has an EGR computer that drives the tachometer.
The base you grabbed is for 84/85 and g@s engine models and is just a diagnostic plug for a mechanic to check engine RPM. The parts you have, except the tachometer, will work for your car but you'll need to get an amplifier from an 82-84 model. The W126 tach will not physically fit in a W123.
I probably misread the door plate. I have a brand new tach amp for an 83, so I should be able just to screw that onto this diagnostic port I pulled, hook everything else up, and the only problem would be the size of the tach itself?
The tach won't fit in the 123? the gauge faces look approximately the same size, is it much larger behind?
EDIT- I see why it won't fit. I wonder if you could pull the gauge stuff out, or cut the back plate and make it fit. Would be way easier to just find the correct cluster.
RE: Adding a tachometer - ForcedInduction - 06-26-2010
Completely different.
RE: Adding a tachometer - techguy512 - 07-17-2010
(06-26-2010, 09:33 AM)dropnosky Im still not completely sure how the tach works on some of these cars without an amp.
Nor am I. I have a 3 pin tach from the EGR controlled set-up, but I don't have the rest of the car to examine, which is really sort of needed to any productive reverse-engineering.
The objective is of course to allow the 3-pin tachs to be used with the 2-pin systems. I have a feeling that EGR computers might become scarce in the future.....
Anyone near Austin, TX with a 3-pin D or SD with working tach willing to help out? I'm trying to determine what sort of signal is presented on pin W. It seems to be nothing like the 2 pin version.
Thanks,
Bob
'82 300D, Petrol Blue-Green Metallic
RE: Adding a tachometer - 85-300Dt - 07-25-2010
Ended up reading about this and stumbled on other possible tach options.
Good thread here that covers it.
http://www.dieselplace.com/forum/archive/index.php/t-198847.html
Auto Meter 2888 "Z-Series" Pedestal Mount Diesel Tachometer - any alt external pickup- on this one
http://performanceparts.com/part.php?partID=166241
Universal Diesel Alternator Tachometer Interface
http://www.dakotadigital.com/index.cfm/page/ptype=product/product_id=128/prd128.htm
Diesel Tiny-Tach (i think hooks up to an injector line)
http://www.tinytach.com/tinytach/diesel.php#
http://teleflexmorse-eu.com/library/instructionmanuals/Tachometer%20Diesel%20Alternator.pdf
http://www.downloadingfiles.co.uk/teleflexfiles/gauges/Diesel%20Alternator.pdf
Auto Rectifier - BB834
http://www.bikudo.com/product_search/details/144377/auto_rectifier_bb834.html
RE: Adding a tachometer - BRABUS - 08-08-2010
(07-25-2010, 09:57 PM)85-300Dt Ended up reading about this and stumbled on other possible tach options.
Good thread here that covers it.
http://www.dieselplace.com/forum/archive/index.php/t-198847.html
Auto Meter 2888 "Z-Series" Pedestal Mount Diesel Tachometer - any alt external pickup- on this one
http://performanceparts.com/part.php?partID=166241
Universal Diesel Alternator Tachometer Interface
http://www.dakotadigital.com/index.cfm/page/ptype=product/product_id=128/prd128.htm
Diesel Tiny-Tach (i think hooks up to an injector line)
http://www.tinytach.com/tinytach/diesel.php#
http://teleflexmorse-eu.com/library/instructionmanuals/Tachometer%20Diesel%20Alternator.pdf
http://www.downloadingfiles.co.uk/teleflexfiles/gauges/Diesel%20Alternator.pdf
Auto Rectifier - BB834
http://www.bikudo.com/product_search/details/144377/auto_rectifier_bb834.html
Anyone tried some of these?
RE: Adding a tachometer - BRABUS - 01-17-2011
bump!
RE: Adding a tachometer - Syncro_G - 01-18-2011
(02-17-2009, 06:39 AM)Gasoline Fumes(02-16-2009, 09:51 PM)winmutt Whats W?
I'm pretty sure that's the signal. I looked at the harness in my '85 300D and the -G pin is not used, only two wires there.
I'm pretty sure -G is ground + is 12V and W is signal. The G-Wagen has a different tach but has the same connectors on the back. Yours may be grounded elsewhere (like via a metal casing) leaving that connection unnecessary.
(07-17-2010, 06:43 AM)techguy512(06-26-2010, 09:33 AM)dropnosky Im still not completely sure how the tach works on some of these cars without an amp.Nor am I. I have a 3 pin tach from the EGR controlled set-up, but I don't have the rest of the car to examine, which is really sort of needed to any productive reverse-engineering.
The objective is of course to allow the 3-pin tachs to be used with the 2-pin systems. I have a feeling that EGR computers might become scarce in the future.....
Anyone near Austin, TX with a 3-pin D or SD with working tach willing to help out? I'm trying to determine what sort of signal is presented on pin W. It seems to be nothing like the 2 pin version.
Thanks,
Bob
'82 300D, Petrol Blue-Green Metallic
Bob,
I converted my 85 engine to use the tach amp when I installed it in my truck. I'm pretty sure the computer was using an inductive signal from the flywheel to drive the tach but the car had both the crank shaft and flywheel sensors so retrofitting was easy. In any case, I have the computer and some harness in a box and both senders still on my truck. If you have the tach, then we have all we need to figure it out. So when you're in Calif, let me know.
-Christian
RE: Adding a tachometer - Walkenvol - 01-19-2011
82 300sd going into a Jeep Comanche...can I transplant this tach system along with my repower?
This is the crank sensor right?
![[Image: WqGP1l.jpg]](http://i.imgur.com/WqGP1l.jpg)
The gray wire from the crank sensor runs to the scan tool connection right?
![[Image: LDhpql.jpg]](http://i.imgur.com/LDhpql.jpg)
And I hope the wiring harness from the scan tool connection is all there is to the dash unit?
![[Image: xwPWIl.jpg]](http://i.imgur.com/xwPWIl.jpg)
The MB dash tach unit and clock appear to be the correct size to fit into the new vehicle. Am I missing something here or is it as straight forward as I'm thinking?
RE: Adding a tachometer - ben2go - 01-19-2011
If you use the Benz tach,you need the Benz wiring.The Jeep engine electronics won't work with the Benz engine.
RE: Adding a tachometer - Syncro_G - 01-19-2011
(01-19-2011, 09:34 AM)Walkenvol The MB dash tach unit and clock appear to be the correct size to fit into the new vehicle. Am I missing something here or is it as straight forward as I'm thinking?
You have the right parts. Properly wired, that should work. Those tach amps (in the lid of the test socket) are known to be fickle. Earlier in this thread you'll see info for Bob's tach amps. If you wanted to keep your original tach, he probably has an amp that will drive it
RE: Adding a tachometer - Walkenvol - 01-19-2011
Ben - my idea was to keep the MB parts shown in the pictures (crank sensor, scan tool connection, and dash mounted tach with clock) and fit them into the Jeep. Obviously, I would keep the MB wiring (or a like substitute) between the 3 pieces. The Jeep tach would be removed from the dash when replaced with the MB tach. Don't know what drives the stock Jeep tach, but the Jeep engine is leaving. What am I missing concerning the "Jeep engine electronics won't work with the Benz engine"?
Syncro - The MB tach and clock were working in the donor vehicle before I pulled the engine so hopefully everything is good? There have been a few other OM617 Jeep repower threads I've followed, and I don't recall one that had a working tach. I would prefer to not have to mess with the Jeep dash to transplant the MB tach pod and would prefer to wire the MB scan tool connection into the Jeep wiring to run the Jeep tach. If there is a way to make that work I'd love to know it!
RE: Adding a tachometer - Syncro_G - 01-20-2011
(01-19-2011, 02:08 PM)Walkenvol If there is a way to make that work I'd love to know it!
it should be pretty simple but you first need to know a bit about the original engine that was in your Jeep. If the jeep tach was fired using the coil, then it's probably a 12V square wave trigger at 3x (straight six) or 4x (V8) per engine rev. Once you know those, then I think Bob (see earlier posts in this thread) can make a custom tach amplifier (fits in the cap of your test socket)
I kept my original tach (matched to a straight six gas engine) and used one of his custom tach amplifiers to drive it using the crank position sensor.
Good luck, Christian
RE: Adding a tachometer - Walkenvol - 01-20-2011
Sent Bob an e-mail and got a response back. Sent him the factory service manual electrical info for the Jeep tach. The Jeep tach has an adjustable potentiometer in the dash mounted tach unit to adjust between different engine choices. Hope he can work something out.
RE: Adding a tachometer - Walkenvol - 01-21-2011
e-mail back from Bob appears hopeful;
"I have written some tach amplifier software that converts the standard "one pulse per rev" output to the standard MB tach to a "two pulse per rev" or a "three pulse per rev" output. This, along with some circuitry that shifts the output level from 5V to 12V works quite nicely with standard aftermarket tachs that are switchable for 4, 6, or 8 cylinder operation, like most are....."
interesting the MB system operates on 5V?
RE: Adding a tachometer - ben2go - 01-21-2011
(01-19-2011, 02:08 PM)Walkenvol Ben - my idea was to keep the MB parts shown in the pictures (crank sensor, scan tool connection, and dash mounted tach with clock) and fit them into the Jeep. Obviously, I would keep the MB wiring (or a like substitute) between the 3 pieces. The Jeep tach would be removed from the dash when replaced with the MB tach. Don't know what drives the stock Jeep tach, but the Jeep engine is leaving. What am I missing concerning the "Jeep engine electronics won't work with the Benz engine"?
Syncro - The MB tach and clock were working in the donor vehicle before I pulled the engine so hopefully everything is good? There have been a few other OM617 Jeep repower threads I've followed, and I don't recall one that had a working tach. I would prefer to not have to mess with the Jeep dash to transplant the MB tach pod and would prefer to wire the MB scan tool connection into the Jeep wiring to run the Jeep tach. If there is a way to make that work I'd love to know it!
Ok I get it.I was half awake, or half asleep,when I read through that and posted.Sorry.I try to do better next time.
RE: Adding a tachometer - 85-300Dt - 01-21-2011
(07-25-2010, 09:57 PM)85-300Dt http://teleflexmorse-eu.com/library/instructionmanuals/Tachometer%20Diesel%20Alternator.pdfi noticed these 2 links for 'diesel tach wiring' have gone dead, a google has lotsa stuff
http://www.downloadingfiles.co.uk/teleflexfiles/gauges/Diesel%20Alternator.pdf
RE: Adding a tachometer - Walkenvol - 02-02-2011
Received this e-mail from Bob;
"I have a unit that puts out a 12V pulse (instead of the normal 5V pulse) with special software for 4cyl tachs or 6cyl tachs. It is used in the W460 G-Wagens with petrol tachs that have had diesels transplanted. It is also used with some aftermarket tachs like Sunpro, etc. for other diesel swaps.
The price is $10 over the normal tach amp ( $59). Keep it in mind as you contemplate your project...."
Strikes me as a better option than attempting to mount the MB dash tach into another vehicle. I plan to give it a shot when I get to that point.
RE: Adding a tachometer - Imaginos - 03-14-2011
I did some research, am I safe to assume installing a tacho on European car (W123 300TDT) would be a major PITA?
RE: Adding a tachometer - ForcedInduction - 03-14-2011
Easy.
RE: Adding a tachometer - Imaginos - 03-15-2011
Yes, I just checked on my car and I think you are right. The reason I asked is that I found that there's supposedly no tach pickup sensor on European 300D, obviously there should be one on 300TD Turbo.
Now I just need to find a tacho.
RE: Adding a tachometer - mike-81-240d - 03-15-2011
Forced are the mounting points already there for the pickup sensor on the non turbo 5 cyl block? I already have 2 tachs, and acess to a turbo parts car in the yard. I just remove the sensor, amp, and all related wiring correct?
RE: Adding a tachometer - 4rnnr33 - 04-15-2011
As Im finishing up my 617 turbo swap into a toyota pickup im trying to find a way to use the factory toyota tach with the diesel. Has anyone had experience with these? http://www.dakotadigital.com/index.cfm/page/ptype=product/product_id=128/prd128.htm
![[Image: tachconverter.gif]](http://i54.photobucket.com/albums/g96/yamarider3/tachconverter.gif)
It says it can use the signal from a flywheel sensor but im not sure about the Crank sensor? And also if it will use the crank sensor do I need the mercedes amp or can I just wire the 3 wires coming of the CPS straight to this converter?
RE: Adding a tachometer - Syncro_G - 04-15-2011
(04-15-2011, 05:05 PM)4rnnr33 As Im finishing up my 617 turbo swap into a toyota pickup im trying to find a way to use the factory toyota tach with the diesel. Has anyone had experience with these? http://www.dakotadigital.com/index.cfm/page/ptype=product/product_id=128/prd128.htm
It says it can use the signal from a flywheel sensor but im not sure about the Crank sensor? And also if it will use the crank sensor do I need the mercedes amp or can I just wire the 3 wires coming of the CPS straight to this converter?
You could try it. Many of the 617A alternators don't have the w terminals so you may end up spending more to get it working.
If your engine has the sender on the front of the crank shaft, you'll likely come out ahead using Bob's custom tach amp as mentioned above.
RE: Adding a tachometer - 4rnnr33 - 04-16-2011
(04-15-2011, 11:38 PM)Syncro_G(04-15-2011, 05:05 PM)4rnnr33 As Im finishing up my 617 turbo swap into a toyota pickup im trying to find a way to use the factory toyota tach with the diesel. Has anyone had experience with these? http://www.dakotadigital.com/index.cfm/page/ptype=product/product_id=128/prd128.htm
It says it can use the signal from a flywheel sensor but im not sure about the Crank sensor? And also if it will use the crank sensor do I need the mercedes amp or can I just wire the 3 wires coming of the CPS straight to this converter?
You could try it. Many of the 617A alternators don't have the w terminals so you may end up spending more to get it working.
If your engine has the sender on the front of the crank shaft, you'll likely come out ahead using Bob's custom tach amp as mentioned above.
Thats what I would rather do but Ive emailed him a couple times and have not gotten a response back. And I would be using the Crank sensor if I used this converter since I dont have the w terminal on my alternator
RE: Adding a tachometer - 85-300Dt - 04-16-2011
(07-25-2010, 09:57 PM)85-300Dt Auto Rectifier - BB834haven't looked at this for a bit ..but i think the idea with this rectifier was that it allowed you to have a W connection where there was none before
http://www.bikudo.com/product_search/details/144377/auto_rectifier_bb834.html
RE: Adding a tachometer - 4rnnr33 - 04-17-2011
Does anyone know if the saab alternators have the w terminal I completely forgot im not using the original mercedes
RE: Adding a tachometer - 85-300Dt - 04-17-2011
what make is the tach? volvo diesel has a bosch with the W
http://auto.pantaiwan.com.tw/proimages/2010112516184938538.pdf
EP130009
also maybe this
http://www.vwdiesel.net/forum/index.php?topic=358.0
Quote:"if you have your alternator cracked open at a rebuild shop of some kind, they can usually tap into the signal you need and give you a terminal to hook up to... even if your alternator didn't originally come with one."
not sure what's going on here "Alternator" 115 Amp Bosch AL129X works in 123s!"
http://www.peachparts.com/shopforum/showthread.php?t=93569&highlight=saab+alternator&page=9
EDIT- http://www.thesamba.com/vw/forum/viewtopic.php?p=4821564
Quote:"I would try to modify a gas one into a diesel one,some people have done it,I found the schematichttp://www.thesamba.com/vw/forum/viewtopic.php?p=4819683&sid=1fc5822e673ba5ebeb152a79406c17bd#4819683
You may need to modify the alternator to add the W connection inside if it has not been done in factory."
RE: Adding a tachometer - 4rnnr33 - 04-17-2011
(04-17-2011, 04:32 PM)85-300Dt what make is the tach? volvo diesel has a bosch with the W
http://auto.pantaiwan.com.tw/proimages/2010112516184938538.pdf
EP130009
also maybe this
http://www.vwdiesel.net/forum/index.php?topic=358.0
Quote:"if you have your alternator cracked open at a rebuild shop of some kind, they can usually tap into the signal you need and give you a terminal to hook up to... even if your alternator didn't originally come with one."
not sure what's going on here "Alternator" 115 Amp Bosch AL129X works in 123s!"
http://www.peachparts.com/shopforum/showthread.php?t=93569&highlight=saab+alternator&page=9
EDIT- http://www.thesamba.com/vw/forum/viewtopic.php?p=4821564
Quote:"I would try to modify a gas one into a diesel one,some people have done it,I found the schematichttp://www.thesamba.com/vw/forum/viewtopic.php?p=4819683&sid=1fc5822e673ba5ebeb152a79406c17bd#4819683
You may need to modify the alternator to add the W connection inside if it has not been done in factory."
So this is telling me I can just swap out the rectifier for one with a w terminal? Ill have to go to the rebuild shop and talk to them tomorrow