Easy DIY Adapter - 5V ECU tacho signal to 12V dial | 924 S Turbo Build 59
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- Опубліковано 8 вер 2024
- Walk through what I did to fix the rev counter not working with the VW Audi engine. The 1.8T engine uses a 5V signal from the ECU to feed the tacho (rev counter). The Porsche tacho dial uses a 12V signal from the ignition coil. This is a relatively easy fix. Some soldering required - you could use choc connectors instead, but it will be a little bigger.
Using:
4 pole relay (preferraly one you can easily take the cover off)
1K Resistor
2N5551 Transistor
Chock box (optional)
Part of the 924 S 1.8T AEB engine swap, installing the VW Audi engine - DIY project, restomod type thing.
Twitter: / pawnsacrifice
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I am a hobbyist mechanic with no formal training, I am sharing what the work I'm doing on my cars, this is not a guide on what to do, but by all means learn from my mistakes... or prototyping, depending on your positivity.
Thanks a bunch mate! Did this for a Mitsubishi 4G91 ECU, retrofitting it to Proton Satria 1.5 VDO RPM Meter (on cluster meter). Works like a charm!
Tried this today on my 1979 BMW 320 where i have swapped the engine and have Maxx ECU engine management. Worked perfect! Thank you so much😃
Note for other people trying this - verify you don't have any voltage back feeding from the tach gauge line - it can blow the transistor pretty easily. For reference, a vw Vanagon with the high oil pressure alarm circuitry may have voltage flowing back from the gauge cluster, and it will kill the transistor. Also, if you hook it up backwards (switch the tach out and signal in), the 5v without a current limiting resistor will carry enough current backwards through the tach gauge output line (now hooked up incorrectly as a 5v signal input) to kill the transistor, and the diode will protect you from that failure mode. I'll try to remember to add which diode I used shortly.
Uf4007 is the diode I used. Soldered inline so the tach signal can go to the gauge but no voltage is allowed back in through that wire.
Amazeballs! Just made my 1.8T Golf MK2 work after following your guide. Thanks a bunch.
1st class explanation. Love the diagrams. I was trying to explainthis to a friend. This explains it far better than i do.
Best video I’ve watched on this thank you for making the time to do this
Thank you! I'm going to try this on a triumph motorcycle.
Hi, this has to be the best video of this out there. As you say, others assume that everyone doing this has a certain level of knowledge already. Not sure if you can answer this? Why do you need the transistor? I got a diagram from an aftermarket ECU maker, showing exactly what you have, less the transistor. I have made up a converter, using the relay housing, removing the contactor, and joining the resistor from pin 86 to pin 87, then it will be connected via spade terminals. 12V to pin 85, tach sig pin 86, ECU output pin 87. Still wiring the engine and transmission, so haven't tried it yet. Thanks for the great video. Cheers
Thanks, and not sure re the transistor, may be for the flow control or failsafe, not sure - I was really just following the original diagram.
Perfecto!!! , pude ahorrar y funciona a la perfección en mi mk2 swap 1.8t ,muchas gracias
Great video. Very helpful. Thank you!
Thanks for this - epic stuff
Dear friend you are the best.we tested on the 205gti 'works great with em221 ecu,we changed resistor to 4'7k
Thanks for the info - may well help others, good work.
Witch engine was that with? I'm trying to get my Peugeot 205 working with the TU5J4, its looking like the same issue Pawn Sacrifice is explaining. Thank you for the video @Pawn Sacrifice massive help.
Very helpfull. Thanks for your time!
About ready to do this. Although a modern 90s suzuki car.. the signal the tach gets is like an older style and requires newer to older style adaptor when you add aftermarket components.
this is very interesting... if the relay isn't using the switch side and is only using the coil... could you just use... a coil? like an inductor? seems like they just want an inductor in that circuit. perhaps they are using an auto relay because they know automotive folks would have those on hand? anyhow, thanks for filming and sharing.
Honestly, I have no idea - I just followed a few different sets of instructions out there, I only put this together following others' work as there seemed to be gaps in other "how to" guides or assumption you know what the diagrams mean.
Sir if a car has no ecu only plug coil and distributor then this diy thing can help me
good tutorial. u know something about noise filtering? i build this to my mk2scirocco but with bd139 transistor and have some noise.
Sorry I don't. Assuming this is right for your setup (I believe there are some difference - if your car does work differently the video will hopefully help understand any documentation - that was my biggest challenge) I would probably check the grounds to see if there is an obvious source for the problem.
to complicated use the same relay housing... put the transistor and resistance inside the relay housing buy a relay connector and do the connections
the best mean
The resistor and transistor thing flys way over my head. I got the tach working using just the coil but wonder if that will mess up the cdi ignition box, which is my situation.
Hi. Excellent video. Would this also work with a diesel tacho designed to receive a 12V alternator (sinusoisal) signal, driven from a 5V ECU pulse please.
Sadly I cannot tell you - I had to follow / patch together instructions and then do research just to get through this.
@@PawnSacrifice hi, I wonder if its the other way around? Like if the signal is a 12v signal going to a 5v tachometer gauge?
thanks! The tachometer still has lower rpm than real, is any way i can improve the circuit to adjust this issue?
To be honest, I'm not sure, you'll need to research that one - if you fix it and update for others would be great. Good luck!
@@PawnSacrifice Thanks! I installed a diode too, maybe if i remove it the rpms will improve...
Hi there...thanks for the video, may I know what kind of ignition coil setup that used to drive the Porsche dial? Is it distributor, wastespark, dumb or smart coil. Thanks
I'm struggling to get the dial (negative coils pickup) working.
The factory Porsche setup uses a distributor. Hope that helps - and good luck!
Hi honest question, how is the STAHLWERK tig welder doing?. would you still recommend it? I'm looking at the STAHLWERK AC/DC MIG 200 ST IGBT £499 Amazon it's a bit cheaper than yours but I hope you might be able to throw some light on the subject before I commit unless the one you got is better.Thanks
The foot pedal or something has gone on mine, still working well for stainless steel but something's not right for aluminium - not helped by me being a total novice. Mine broke in the early days and had it sorted under warranty but needed shipping back to Germany, that would be an expensive and lengthly exercise now. If you get a TIG check Hobbyweld for the gas.
Hey! Where have you got to? Been a while...
Erm... couple "smaller" jobs and things in the background not worth filming (and far too many other things to get done away from the car). I am in the middle of something that'll hopefully be up soon.