tdi conversion rev clock inaccurate

Post by **wozza825y** » 21 Jan 2015, 21:10

hi, just completing a 1z tdi engine conversion to my syncro pickup, which has taken a lot in both terms of money and time, anyway my original clocks didn't have a rev clock so i fitted my speedo head into a diesel rev clock binnacle and connected it all up it works great but with engine at tick over it reads around 1400 rpm. I have read that you can adjust the potentiometer at the rear of the rev clock with a screw driver. any body any the wiser?
cheers warren

Post by **lloydy** » 21 Jan 2015, 21:56

Theres a little sticker on the back, peel it off and you'll see the screwdriver adjustment. It will never read that accurate though as the alternator is different

Post by **ninja.turtle007** » 21 Jan 2015, 22:44

As Lloyd said it won't be that accurate.

Sell the rev counter setup and buy a Scanguage. Spend the rest on beer.

Post by **wozza825y** » 22 Jan 2015, 22:47

cheers for that, has nobody made a gizmo to alter signal from new alternator to fool rev clock? or something along them lines, thanks for the replys.

Post by **ninja.turtle007** » 22 Jan 2015, 23:10

Wouldn't be just having the correct ratio pulleys?

Post by **Timburrows** » 23 Jan 2015, 07:41

ninja.turtle007 wrote:Wouldn't be just having the correct ratio pulleys?

What he said your crank pulley is probably larger by 50% circumference giving you the 1400 rpm tick over

Post by **VirginAtlantic** » 29 Jan 2015, 17:42

I've got a similar problem. I fitted my AHU MTDI 1.9 and wired the alternator as you do. But when I started the engine, my rev clock remained still.

Any ideas?

the alternator is producing a current for a rev meter so its working, is it a different pulsar on this alternator to the previous 1.6TD alternator?

any ideas would be appreciated

Post by **wozza825y** » 29 Jan 2015, 18:34

I am using the alternator from the mk3 golf 1z engine, 70 amp with a two pin connector at the back, one is the dash battery light and the other is for the rev clock. i just plugged it in and it worked but used the short loom from the rear of the alternator to battery from the mk3. are all your connections good/ have you had the dash out, the connections can be a bit crappy on the dash plug. can't really think of anything else, let me know if you find anything. warren

Post by **VirginAtlantic** » 29 Jan 2015, 18:56

The battery light doesn't light up on the dash when the engine is running so its charging the battery

I've wiggled and giggled the dash connector while running the engine but the rev's still doesn't come alive. I've revved the engine and nothing on the needle?

Post by **wozza825y** » 29 Jan 2015, 19:33

have you checked connections in the engine bay fuse box, if they are ok i would check continuity between alternator and dash plug. was the dash working before engine change ?

Post by **lloydy** » 29 Jan 2015, 20:42

Mine didn't work, ran a new wire wire from alt to connector on dash pod and it did

Post by **VirginAtlantic** » 29 Jan 2015, 22:37

yes the previous engine was working the rev counter but the new alternator doesn't, apparently its the biggest alternator on the 1.9 TDI engine you can get.

I have been e-mailing a friend of mine on here, and it appears the Rev's are taken off the crank case sensor not the alternator. The connection on the plug of the alternator is not connected internally for the rev counter but is connected only for the battery light led. He suggests opening up the back of my alternator and solder in a wire to the plug. I would assume this is only if you are using the 120 amp alternator and not the 90 amp I forgot to ask where this wire actually comes from inside the unit to the plug! Apparently there is a youtube video on this. If you can find it you're better than me.

Post by **lloydy** » 30 Jan 2015, 07:38

Some pics on my build thread of me opening the alternator up and connecting to one of the phases for the W signal
Also you can do it on any alternator

Post by **VirginAtlantic** » 30 Jan 2015, 17:54

thanks Lloydy found your piece - which prong works the rev counter any or specific one?

https://club8090.co.uk/forum/viewtopic.p ... l#p7987418" onclick="window.open(this.href);return false;

got my alternator out, where does that wire go again!

Post by **lloydy** » 30 Jan 2015, 18:19

Good, you found it. I had a look while at work and couldn't..was looking at my other build thread

I chose the middle phase, apparently they all give a slightly different pulse... I can't comment on whether the middle one is best as I never connected me me up, I went for Andys dashpod which takes the revs from the ECU

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tdi conversion rev clock inaccurate

tdi conversion rev clock inaccurate

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