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The Believer
Samba Member
Joined: April 07, 2020
Posts: 11
Location: Hillsborough, New Hampshire
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 Posted: Thu Sep 23, 2021 7:12 pm Post subject: Re: Aftermarket Tachometer |
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I have a 90 Syncro and tried to install the Autometer 2306 & 2300 Tachometer with the inline noise filter 9116 with no luck.
I tired numerous grounds and tach signal pickups. The 2300 with 9116 got a bouncy unreliable needle.
Would love to have just bolted in a stock cluster with tach if they weren't becoming increasingly rare and overpriced. |
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djkeev
Samba Moderator
Joined: September 30, 2007
Posts: 32646
Location: Reading Pennsylvania
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jsmiller
Samba Member
Joined: June 09, 2011
Posts: 24
Location: South Australia
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| Posted: Sat Feb 21, 2015 3:46 am Post subject: |
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Ok folks success!! I wired the signal filter (Auto Meter model number 9116) in before the Tach as instructed and it WORKS!!!! Many thanks all
for the advice! |
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jsmiller
Samba Member
Joined: June 09, 2011
Posts: 24
Location: South Australia
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| Posted: Fri Feb 06, 2015 8:28 pm Post subject: |
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Thanks for that Dave!!
I had e-mailed Autometer as well so I got the same response from Cory!
I'm got going to order the signal filter he suggested and see what happens.
Thanks again Dave for your help! |
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djkeev
Samba Moderator
Joined: September 30, 2007
Posts: 32646
Location: Reading Pennsylvania
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| Posted: Fri Feb 06, 2015 4:46 pm Post subject: |
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Well....... I've the 86 Multivan with a BIG clock but no Tach...... So I guess I've got a Dog in this fight.......
I wrote to the company, referred them to this link and asked if they had feed back or suggestions......
Here is their response....... It's long...... Get a cup of coffee first! 
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Hello.
I have read through the forum, and while I do not have a definitive answer (impossible to give without have the van, the tach, or both in my presence to inspect & test), I can give you some tips & information.
First, the suggestion of using a resistor in line was a good suggestion. The resistor simply acts like a bit of a filter to help filter out spikes in the signal which can cause a jumpy pointer. I do not know why the user is hesitant on trying a resistor, but opted to try a diode. A diode is a one way check valve and does nothing to clean up a dirty signal. Resistors are cheap, so I recommend to try it.
We also offer a tachometer filter which was originally designed for the same symptoms when used on both points & electric ignitions on the VW's with Bosch distributor. I was directly involved with the research on this. Where the simple resistor fix did not help the tachometer filter did. The filter is an Auto Meter model number 9116. It is imperative when wiring this, that it gets grounded to the engine.
When wiring the tachometer itself (regardless of what the previous tachometer acted like), I recommend grounding it to the engine as well. If the tachometer has a weak or insufficient ground, it is unable to cancel/filter out ignition noise as efficiently as it otherwise could.
I do also recommend connecting to the negative side of the coil which on my diagrams through Alldata for US Versions appears to be a green wire.
In order to check the tachometer, you may simply perform a temporary hook up on another vehicle to see how the tachometer reacts. Comparing to an unknown brand of tachometer is not always the best solution, and here is why. While tachometers all give you essentially the same information (how fast an engine is spinning), a tachometer can react very differently from the next based on its input circuitry, its meter type, level of dampening, and quality of components used to build the circuit. For example, Auto Meter tachometers are built with a fine balance with its level of dampening in order to have a tachometer that is performance orientated, and able to respond quickly, and to still try and dampen it enough to keep the pointer calm in low pulse frequency situations, or dirty ignition signal situations. With that said, if the previous tachometer had heavy dampening it can do a better job of filtering out what is happening, though would be a slow responding tachometer as a result.
I hope this has been helpful, and look forward to hearing the results.
Thank you
Cory
Tech/Service
Auto Meter Products
413 W Elm St.
Sycamore IL 60178
866-248-6357
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crazyvwvanman
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Joined: January 28, 2008
Posts: 9941
Location: Orbiting San Diego
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| Posted: Thu Feb 05, 2015 8:54 am Post subject: |
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Yep, the Digifant tachs work in some cases. Many times not and they are known to behave differently from other tachs. As an example, read this from instrument maker Dakota Digital, for one of their tach related products.
"Product not compatible with '86-91 VW Vanagon's and other similar models"
http://www.dakotadigital.com/index.cfm/page/ptype=...prd128.htm
Mark
| Gauche1968 wrote: |
| crazyvwvanman wrote: |
There is a known issue with the tach signal on Digifant 2.1 models. The tach made for that works but other tachs often don't. Even the tach from an earlier Digijet can act crazy if hooked to the Digifant. Likewise the factory tach for Digifant models is known to give problems when you are trying to use it with something other than a Digifant.
Mark
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Using two Digifant tachs on Digijet without any problems.... |
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Gauche1968
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Joined: April 13, 2006
Posts: 1518
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| Posted: Thu Feb 05, 2015 8:40 am Post subject: |
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| crazyvwvanman wrote: |
The tach wire on the dash cluster 14 pin connector comes from the coil negative side anyway, which is also connected to the ECU since the ECU is what fires the coil. (on USA/CA vans the tach signal is on pin 9 of 14)
There is a known issue with the tach signal on Digifant 2.1 models. The tach made for that works but other tachs often don't. Even the tach from an earlier Digijet can act crazy if hooked to the Digifant. Likewise the factory tach for Digifant models is known to give problems when you are trying to use it with something other than a Digifant.
Mark
| jsmiller wrote: |
| I'm getting the signal from the the tach wire that goes to the cluster (pin 14??). But I've also wired it directly to the negative side of the coil and same thing happens! |
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Using two Digifant tachs on Digijet without any problems....
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djkeev
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Joined: September 30, 2007
Posts: 32646
Location: Reading Pennsylvania
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jsmiller
Samba Member
Joined: June 09, 2011
Posts: 24
Location: South Australia
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| Posted: Thu Feb 05, 2015 2:02 am Post subject: |
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Well someone suggested putting a diode in line with wire from the coil. So I tried it when i got home from work. It was worth a try I guess. But it didnt work, same issue diode or not?
How can the signal from the negative side of the coil have such a erratic pattern to we're a standard tachometer won't read it and the car still run? I'm starting to get pretty frustrated here. Especially because in sure it's a very simple answer!
Anywoo back to square one. |
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Merian
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Joined: January 04, 2014
Posts: 5212
Location: Orygun
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| Posted: Wed Feb 04, 2015 3:29 pm Post subject: |
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cars & tachs differ in how they do the pulse counting - e.g Porsche changed their method in the early 1970s
if the resistor doesn't work you might put a scope on the Van's trigger wire and see what it looks like |
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crazyvwvanman
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Joined: January 28, 2008
Posts: 9941
Location: Orbiting San Diego
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| Posted: Wed Feb 04, 2015 3:23 pm Post subject: |
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Most of our vans here came with tachs, the vast majority have them starting with 1985. Until recently they were easily available second hand at a reasonable price for people who wanted to add one.
Mark
| jsmiller wrote: |
Ok I've heard that putting a diode in line with the signal wire might work? And someone on another forum said they used an 'older' VDO brand tach on their 89 and it worked?
Come on guys, surely there's a answer to this? I thought this would be a no brainer on here? Maybe it's more complicated than I thought? |
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jsmiller
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Joined: June 09, 2011
Posts: 24
Location: South Australia
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| Posted: Wed Feb 04, 2015 3:14 pm Post subject: |
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Ok I've heard that putting a diode in line with the signal wire might work? And someone on another forum said they used an 'older' VDO brand tach on their 89 and it worked?
Come on guys, surely there's a answer to this? I thought this would be a no brainer on here? Maybe it's more complicated than I thought? |
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jsmiller
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Joined: June 09, 2011
Posts: 24
Location: South Australia
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| Posted: Tue Feb 03, 2015 8:26 pm Post subject: |
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| There's a video on YouTube by a 'mercedesdieselguy' where he had a similar issue when putting a tach in his 91. He did the resistor thing and it was no help? Hey I'd try it no worries just looking for a bit more of a solid confirmation that a fix actually does exist? |
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wcdennis
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Joined: July 20, 2004
Posts: 955
Location: Winston-Salem NC
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| Posted: Tue Feb 03, 2015 8:09 pm Post subject: |
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| Is it not worth even trying the resistor fix? |
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jsmiller
Samba Member
Joined: June 09, 2011
Posts: 24
Location: South Australia
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| Posted: Tue Feb 03, 2015 6:31 pm Post subject: |
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Thanks for that info Dave, however I don't believe this is and installation issue and is likely related the type of signal from the negative side of the coil specific to Digifant? Most tachometers rely on a 'square' type signal (I.e. on/off pulse from the coil) of which I'm starting to think (based on my research thus far) the Digifant system does not produce for reasons still unclear?
I'm tring to determine:
1. It's the signal from my Digifant coil unreadable by my new tachometer, and if so is there a solution? Different aftermarket tach that will work or some type of signal filter that will fix the issue; or
2. Is my newly purchased (Autogage 2300 tachometer) just broken?
As mentioned previously it appears to be a signal issue, that others have potentially also experienced? If any of you vanagon gurus can clear this up for me that would be much appreciated. |
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djkeev
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jsmiller
Samba Member
Joined: June 09, 2011
Posts: 24
Location: South Australia
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| Posted: Tue Feb 03, 2015 3:01 pm Post subject: |
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Ok pin 9 then, the green wire, the one the current tach is hooked too.
| crazyvwvanman wrote: |
| There is a known issue with the tach signal on Digifant 2.1 models. |
Well I'm thinking this must be the issue, but is there a known fix, or aftermarket tach that can read the signal? While I'd love to put a factory in dash tach in there, I've already got holes drilled in the dash for the tach that's there now. Plus a $60 aftermarket tach is way cheaper than and easier to find than a factory one. |
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crazyvwvanman
Samba Member
Joined: January 28, 2008
Posts: 9941
Location: Orbiting San Diego
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| Posted: Tue Feb 03, 2015 2:20 pm Post subject: |
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The tach wire on the dash cluster 14 pin connector comes from the coil negative side anyway, which is also connected to the ECU since the ECU is what fires the coil. (on USA/CA vans the tach signal is on pin 9 of 14)
There is a known issue with the tach signal on Digifant 2.1 models. The tach made for that works but other tachs often don't. Even the tach from an earlier Digijet can act crazy if hooked to the Digifant. Likewise the factory tach for Digifant models is known to give problems when you are trying to use it with something other than a Digifant.
Mark
| jsmiller wrote: |
| I'm getting the signal from the the tach wire that goes to the cluster (pin 14??). But I've also wired it directly to the negative side of the coil and same thing happens! |
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jsmiller
Samba Member
Joined: June 09, 2011
Posts: 24
Location: South Australia
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| Posted: Tue Feb 03, 2015 1:41 pm Post subject: |
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| I'm getting the signal from the the tach wire that goes to the cluster (pin 14??). But I've also wired it directly to the negative side of the coil and same thing happens! |
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MarkWard
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Joined: February 09, 2005
Posts: 17157
Location: Retired South Florida
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| Posted: Tue Feb 03, 2015 9:19 am Post subject: |
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I guess we need to know where you are getting your rpm signal from the ECU or directly from the ignition coil.
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