tdi conversion rev clock inaccurate

[VirginAtlantic]

I'm in exactly the same boat as Warren. I did adjust the screw behind the sticker down to 1000 RPM but when I accelerate the rev's go off into their own world. Nothing is accurate after tick over. I did discover when I wired it incorrectly I got the revs at 900 but the battery light wouldn't go out! headache.

In the words of Warren "has nobody made a gizmo to alter signal from the new alternator to fool rev clock or something along them lines?" I was thinking along the lines of inserting an inline resistor in the w signal wire. has anyone out there beaten this problem other than fitting a separate rev counter???

[wozza825y]

I was thinking of connecting the mk3 dash up to the ecu just to see how far out the rev clock is, surely somebody must have an idea how to fool the rev clock.

[VirginAtlantic]

ok, I think I have the answer - but I'm not yet wholly committing to this so please bear with me on this one. of course if someone has beaten me to this then "Where the hell have you been?"

I'm now leaning in this direction - you'll need a VW T3 Diesel Rev or Tach clock instrument in your bus and this a Dakota Digital



They are priced at $66 on ebay.com but look away at the shipping costs!

This manufacturers states - "Product not compatible with '86-91 VW Vanagon's and other similar models" - I've read success stories by Vanagon owners in the US using a diesel Rev Counter. If Dakota Digital are aiming this product at the US market and as, I assume, the majority of US Vanagons are petrol, perhaps they're assuming this product will not work on TDI conversions into petrol Vanagons but not thought about TDI Conversions into Diesel Vanagons?

I must put in a disclaimer:- I do not know whether this will fix my problem, so if you decide to try, on your head be it!

i'm going to try this and let you know the outcome.

[VirginAtlantic]

I Sent Dakota Digital some emails - I've decided to publish them for your interest

Dear Dakota Digital
I have a VW Vanagon with a 1.9 TDI Rabbit engine fitted with a 120 Amp alternator/generator. The W+ connection is not sending a compatible signal to the original Rev dial. Do you have available a frequency conversion box to alter the signal to allow the use of the original Rev instrument? Any help would be appreciated. Have you had this same question asked by anyone else?
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Thank you for the email. Is this a mechanical tachometer or a electronic one?
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Hi Justin
Electronic Tacho - The engine is a AHU 1.9 TDI 1996 with the 120 amp alternator, the removed engine was a VW 1.6TD JX 70 amp alternator. I've connected the engine up and the revs are running about 2500rpm while the engine is just ticking over at 900rpm. hope this helps
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Hi Justin
RE: VW 1990 Vanagon 1.6TD now with 1.9 TDI AHU Engine installed.
Just to follow up on my previous email to you (below). Have you had any luck with an answer to my query? I've noticed that you sell a product DSL-1 but it states :-
"Product not compatible with '86-91 VW Vanagon's and other similar models" Is this directed at Gas Models, Diesel models or both Vanagon model engines? I know my original VW instrument cluster is set up as a diesel by it's original 1.6TD JX engine. Therefore would this make a difference in the use of your DSL-1 to my vehicle? Opposed to a Gas instrument Tach's in many US vans between 1980-1991 Vanagon's? It appears to be a common problem with this vehicle on the forums, some Vanagon members write that they have had success using your DSL-1 only with the use of a VW diesel Tach. Have you any knowledge of this?
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We’ve done some digging and I’ve been in touch with our tech’s on this topic. The SGI-5 MIGHT work, but we’re going into unchartered waters here! It’s a complete unknown! Still digging though! Justin Olsen Dakota Digital.


This really is a topic no one is prepared to commit to.....so we must continue to learn. just a thought any club members with a friend in VDO?

[lloydy]

i presume you have tried the adjuster on the back?

[VirginAtlantic]

Yes it's works but the voltage in the Rev instrument is to high and the needle just wants to run away when you increase the Rev's. I would guess by 50%.
I've read some forums about Subaru conversions where resistors are removed and replaced. but noting about the Diesel Rev clock with a 70 amp to a 120 amp alternator.

I have also been emailing a friend who mentioned It should work without any adaptors. You have to find the terminal on the alternator that give approximately 7 volts (probably before the diodes). The rev counter should give 1200 rpm at idle, then adjust with the screw on the back of the revcounter. It should be possible, hundreds of tdi conversions outthere

This is something I did try and it worked but the battery light on the dash just wouldn't go out, and now thinking about It, I didnt rev the engine to see the results! - perhaps I should just disconnect the LED for the battery and run with this?

[lloydy]

you can fit a petrol T3 rev counter and connect it to the rpm signal from the ecu, via one of the adapter things you've linked to. Pretty sure kingprawn done this among others. Ill try to find it...

[lloydy]

http://forum.club8090.co.uk/viewtopic.p ... i#p8030765" onclick="window.open(this.href);return false;

[VirginAtlantic]

My conversion is Mechanical

[lloydy]

Aahh.....