Definitive Aftermarket Tacho Convertor

[chownr 0]

OK

 

Ive done a search an dcompletely confused myself. Having now got my Omex up and running I was hoping to run the tacho on my 205 off the ecu output. But sods law its not doing anything so I figure my choices are a convertor, change the clocks to a later style (bx etc) or an adaptor of the coil. id really like to simply use the ecu output (albeit converted) then simply plug into wire 112.

 

Is this feasible? Can anyone point me in the right direction to make or buy one (cheaply!!) or have I lost the plot altogether?

 

Thanks in advance

 

Rich

[allanallen 528 2 Cars]

OK

 

Ive done a search an dcompletely confused myself. Having now got my Omex up and running I was hoping to run the tacho on my 205 off the ecu output. But sods law its not doing anything so I figure my choices are a convertor, change the clocks to a later style (bx etc) or an adaptor of the coil. id really like to simply use the ecu output (albeit converted) then simply plug into wire 112.

 

Is this feasible? Can anyone point me in the right direction to make or buy one (cheaply!!) or have I lost the plot altogether?

 

Thanks in advance

 

Rich

 

QEP do a little gizmo for about £40 that'll convert it i think. Theres also a diagram knockin about on here showing how to do it with a few resistors. al

[All Praise The GTI 3]

spiky may be able to help you. drop him a pm

[Super Josh 4]

Rich, you could also mod the tacho pcb and bypass the input resistor. This has been known to work. Drop me a PM if you like and I could come round one evening after work and we could try it out.

 

 

 

Josh

[Toddy 7]

Rich, you could also mod the tacho pcb and bypass the input resistor. This has been known to work.

Josh

 

That is how my GTI6 engine is done, with standard management, iirc wire 112 input straight to pin 1 of the chip bypassing the resistors, quickest & cheapest way!

 

I tried a QEP convertor on mine and it didnt work.

[welshpug 1,621]

That is how my GTI6 engine is done, with standard management, iirc wire 112 input straight to pin 1 of the chip bypassing the resistors, quickest & cheapest way!

 

I tried a QEP convertor on mine and it didnt work.

 

odd, I tried that and it didn't work at all so I made an adapter like the one that Spiky can supply.

[Toddy 7]

odd, I tried that and it didn't work at all so I made an adapter like the one that Spiky can supply.

 

Looking at the post you made

 

http://forum.205gtidrivers.com/index.php?s...st&p=719815

 

You connected the input to pin 14 not pin 1 which explains why it didnt work for you!

[pug_ham 240 3 Cars]

Connecting to pin one does work, iirc Alex (Bales on here) has managed to do it that way with no problems.

 

Also Merian, you had two signals running to the chip with your extra wire fitted to the chip pin from the pcb join. The original wire to the pcb should be removed & fitted directly to pin 1 for it to work.

 

I make converted 205 rev counters with the digital internals from a later coilpack equipped car's rev counter that plug straight into the 205 loom with no extra wiring.

 

Graham.

[welshpug 1,621]

still unsure where I went wrong, I did interrupt the original path might take you up on the converted rev counter though Graham, how much do you do them for? (I can supply the original rev counter)

[petert 549]

I did another one today and can verify it works fine if you bypass the input resistor and capacitor. I find it easier to solder the jumper wire to the Pin 1 side of the capacitor, as it's near the corner of the board. Then you don't have to completely disassemble.

[chownr 0]

OK Im having a go at bypassing the input resistor in an attempt to get my Tacho working. Clocks came out without incident, even managed to strip the binnacle down part way last night but Im stuck getting the Tacho out of the front section of the binnacle. How do you get the needle through the binnacle? or do you dismantle the whole back section of the tacho? Sure Im missing something really easy here. Any advice gratefully received before I have another tantrum!!

 

TIA

 

Rich

Edited March 20, 2008 by chownr

[chownr 0]

OK so I think ive answered my own question now. Just prized the needle off carefully (I used a couple of knives and used the mounting screws as leverage) and that lets you access the circuit board. now ive just got to add a jumper wire and hopefully we will be in business

 

Rich

Edited March 20, 2008 by chownr

[pug_ham 240 3 Cars]

I did another one today and can verify it works fine if you bypass the input resistor and capacitor. I find it easier to solder the jumper wire to the Pin 1 side of the capacitor, as it's near the corner of the board.

Peter, could you post a picture of one you've converted to show where you have soldered the wire to help with any future people looking at this conversion?

 

Graham.

[tidypug 5 2 Cars]

Thought i'd bring this thread back up as i couldn't find a definitive answer to say this is how you mode the rev counter.

I can confirm that you need to put a link wire in just like Welsh pug did.

http://forum.205gtidrivers.com/index.php?s...st&p=719815

[pug_ham 240 3 Cars]

Miles has wired a rev counter in with the input going directly to pin 1 of the chip & I'm hoping to do one this week before trying it in my car to also prove it works with no extra wiring etc needed.

 

Graham.

[Miles 331 1 Cars]

As Graham's said, I've tested 3 like this now and they all work spot on, Yet to try it with a GTi6 loom but I can;t see why it wouldn't

[tidypug 5 2 Cars]

it's worked fine with mine, i thought i'd post a definitive reply as i was searching through and could only find the question but no real answer

[Super Josh 4]

This is what we did with Rich's (Chownr's) Tacho and it works fine. I jusr desolder the signal wire and tack it onto the leg of one of the resistors, this way you don't need to disassemble the tacho

 

 

 

Josh

[pug_ham 240 3 Cars]

I've now got everything ready to do this so just to make sure I wire it right first time, which wire from the pcb do I reposition to chip 1 on the pin?

 

Yellow as shown in WP's picture below?

 

 

Graham.

[Toddy 7]

I've now got everything ready to do this so just to make sure I wire it right first time, which wire from the pcb do I reposition to chip 1 on the pin?

 

Yellow as shown in WP's picture below?

 

 

Graham.

 

 

Yes, exactly as that.

[pug_ham 240 3 Cars]

 

Thanks, good job I asked.

 

I was to busy at work last night but I was going to use the blue wire thinking it carried on the normal rev counter signal wire colouring.

 

Graham.

[pug_ham 240 3 Cars]

As an update on this topic, I've modified two rev counters with the wire running to pin 1 of the chip but unfortunately it doesn't work on MP3.1 (confirmed by Miles yesterday) so I haven't been able to check it works on my car.

 

 

Strange that it doesn't work though because the one's I've done before where I fitted the internals from a later car's rev counter work on MP3.1, MM8P & various other systems (Omex etc) but this mod doesn't work in reverse. Hopefully I be able to check if this mod works on MM8P next weekend.

 

The wire runs through the pcb solid, not soldered either side before anyone suggests I've wired it up wrong. I drilled the pcb hole out to feed the wire through to keep it neat.

 

Graham.

[Cameron 16]

Im going to try this out but first I think I should check that I have my rev counter wired up correctly. I made new looms for my 205 using the old looms as a guide but there was some confusion around the rev counter. Could somebody quickly explain which pin of the 4 pin connector is for what? Eg pin 1 tacho signal, pin 2 earth (probably not that at all, just an example). Would be much appreciated.

[pug_ham 240 3 Cars]

IIRC the plug on the car loom should be pin 1 12v power, pin 2 earth & pin 3 tacho signal.

 

AFAIK all cars only have three pins in the car loom plug as standard but some rev counters have four wires from the plug to the counter pcb (the random fourth wire goes to the same place on the pcb as the wire from pin 3 on the clocks plug).

 

Graham.

[Cameron 16]

Aha so I'm missing the +12v then! That could help.

 

Thanks for that, I'll try it out today.