quattro Posted October 1, 2017 Share Posted October 1, 2017 (edited) Hi all, Most things working now and the car takes off like a scalded cat, drives nicely, starts well, etc. very please with the transformation from the four barrel Two problems still though, 1/. a bit of hunting now and then, which I'm sure I will chase down and sort completely very soon, and 2/. The Tacho - now that is driving me nuts Very long story, but I'll keep it as short as I can. End of 2016 I contacted a company who sells a device called a 'tachfix.' After conducting a few tests, like attaching the IDM to the tacho, where it made the tacho jump a little when engine turned on, and again when it turned off, nothing when running. I then disconnected the orange wire on the EDIS and brushed it against a ground with the ignition on, and the tacho jumped to 500 - 1,00rpm every time I did it. I then connected the SAW to the tacho and that worked but was reading 100rpm low, not a problem, that would do. He gave me two options, the one I chose was to send him the ECU and he fitted a tacho output, which connected up to the Tachfix. It arrived back and I connected it up, red to ignition live, black to earth, orange to new tacho output wire and yellow to tacho. Fired the car up, the tacho burst into life but the needle just bounced up and down. I have uploaded a video of the tacho with the tuner studio one next to it. The only other thing, which may or may not be connected is a strange reading from the "Rear bank O2 voltage," which shows the needle pinned to the end of the gauge, as in the pic attached. The car is ticking over when this is happening. I was just wondering if, somehow the output for the tacho is pointing at the O2 gauge instead? I don't know how or why, just guessing. Any ideas anyone? Richard Tacho.mp4 Edited October 1, 2017 by quattro Quote Link to comment Share on other sites More sharing options...
Quagmire Posted October 1, 2017 Share Posted October 1, 2017 Not sure what's going on but I use the tach out circuit to drive a relay with its guts removed to leave just the coil as per here: http://www.msextra.com/doc/ms2extra/MS2-Extra_Hardware.htm#tachoout Its dead accurate! Quote Link to comment Share on other sites More sharing options...
garrycol Posted October 1, 2017 Share Posted October 1, 2017 Not sure I totally follow but I take it you are after a correct reading tacho rather than rev input to the MS which should come from the trigger wheel. If so I had the same problem with my Edis 8 setup. I have a standard aftermarket tacho and it would not work but was OK with the old points and coil system I had. I made up one of these and it works a treat. This is is for EDIS 8 using wasted spark and be modified to suit other configurations - the left side is the input from EDIS to the coils and the right side is the signal to the tacho - worked fine for me. If you are having problems getting a tach signal to MS then please ignore. Garry Quote Link to comment Share on other sites More sharing options...
quattro Posted October 1, 2017 Author Share Posted October 1, 2017 Thanks to both of you I am however not brilliant at electronics. I can follow and make wiring looms, which I have done of course, but really not sure about making up these circuits. If all else fails though, I will try the 4 x 1N4004s in Quagmire's post. As I have a wire fitted to the ECU as a tacho output, a tachfix, and a Tacho which 1/. Worked with the coil set up, and 2/. a spare Tacho I have does the same and jumps, I can only assume that something is wrong with either the output wire or the tachfix. I was hoping that there is something in Tunerstudio was pointing in the wrong direction and that I could just hit a few keys and get it to work - now there's optimism for you Is there any way, with the help of a multi meter that I can check the output wire and the tachfix? I have done some basic testing - does this lot look right? Ignition off, I checked from the wire at one side of the connectors to the wire at the other side, to check for any resistance. None at all for any of them, so connectors are ok. Resistance from yellow wire on Tachfix to back of tacho - 0.04 ohms. Black wire on tachfix to chassis - 0.04 ohms. With the ignition on, all connected: - Red 12.58V Orange 0.81V Tachfix to ECU Yellow 0.04V Tachfix to tacho Black 0V Engine running Orange 0.06 to 0.13V Yellow 13.6 to 14V Richard Quote Link to comment Share on other sites More sharing options...
quattro Posted October 7, 2017 Author Share Posted October 7, 2017 (edited) Right, I got one of these, a box to put it in and chopped it to size. Then I purchased 4 x 1N4004 diodes and a 1N5355B Zener Diode and popped them in Soldered them all in And then connected the brown (plus tracer) wires to their respective colours on the wires to the coilpacks. Then the Zener to the tacho. Start the car and the tacho works, sittting there stable pointing ta 800 rpm which according to tunerstudio is correct Slowly increase the revs and the needly rises following tunerstudio, so excellent - UNTIL it reached 1,300 rpm when the needle just drops. So, I have The voltage from the purple/white wire to the tacho is around 7V on tickover, but goes up when the engine is revved, if that's any help? Have I done something wrong here? I have copied the diagram in Quagmire's link exactly Edited October 7, 2017 by quattro Quote Link to comment Share on other sites More sharing options...
quattro Posted October 7, 2017 Author Share Posted October 7, 2017 Video of tacho behaviour Tacho 1300.mp4 Quote Link to comment Share on other sites More sharing options...
garrycol Posted October 8, 2017 Share Posted October 8, 2017 You should have followed my circuit above - it works :-) Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted October 8, 2017 Share Posted October 8, 2017 So does the diode circuit above, for me... Does the tach work on another vehicle, even 4 cylinder, for testing? Quote Link to comment Share on other sites More sharing options...
Quagmire Posted October 8, 2017 Share Posted October 8, 2017 Sorry! I should have been a bit more precise with my link- it took you to the section on tach out in the msextra manual, which covers all the methods of generating a tach signal. I used a relay coil to emulate the old ignition coil, which is the third diagram down: Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted October 8, 2017 Share Posted October 8, 2017 @Quagmire, not used/seen that one before, looks a good option for sure! Quote Link to comment Share on other sites More sharing options...
quattro Posted October 8, 2017 Author Share Posted October 8, 2017 4 hours ago, Bowie69 said: So does the diode circuit above, for me... Does the tach work on another vehicle, even 4 cylinder, for testing? I don't have another vehicle, but I do have a 4 cylinder tacho. I tried this on my car with the tachfix and it did exactly the same as the 8 cylinder one, i.e. just bounced around. I haven't tried it yet with my made up box of tricks, but I will do shortly. Quote Link to comment Share on other sites More sharing options...
quattro Posted October 8, 2017 Author Share Posted October 8, 2017 3 hours ago, Quagmire said: Sorry! I should have been a bit more precise with my link- it took you to the section on tach out in the msextra manual, which covers all the methods of generating a tach signal. I used a relay coil to emulate the old ignition coil, which is the third diagram down: Hi Jamie, yes I realise that as I remember you using the relay in your build. I am not good at electronics, in fact this is the first time I have ever soldered anything into a board, so I wasn't confident enough to go into the ECU and add a tach feed wire. I sent it off to get it done from the same person who supplied the tachfix. As this didn't work, I don't know if I can trust the feed wire, so had to take the fourth option and take feeds from the coils. This system obviously works as the tacho is smooth right up the 1,300rpm:) which is 36mph in top, but it just breaks down above that. I have found this on a google search last night so might have a try at it:- ".......... you can try removing the zener and replacing it with a resistor of between 330R and 1K, the zener is not actually there to limit voltage to 18V, it is there to block the 12V present at steady state. Further, the IN4004 diodes will not really conduct well into an open circuit (which you effectively have with the zener there). An alternatve approach would mean adding a resistor of between 1 and 10K after the IN4004 diodes to ground BEFORE the zener, this will allow current to flow through the IN4004's properly and should allow the zener to break down as you expect." What could possibly go wrong ? Quote Link to comment Share on other sites More sharing options...
quattro Posted October 10, 2017 Author Share Posted October 10, 2017 So, I removed the Zener and replaced it with a 1K resistor, now it doesn't work at all For complicated reasons I can only make the box of tricks up at home, then go to the car and fit it, making it difficult to actually adjust it when fitting, so I have decided to buy a few bits and pieces in and make up a few different types to try. They're not really expensive and it does give me extra confidence in building these things @Quagmireis it obvious which way to connect that 2N5551?, does it matter what wattage the 1K resistor is, and do I take it that 0V means earth? I have googled the 4 x 1N4004 fix and found that it does indeed have problems, with someone saying his car ran like a bag of nails, some only starting to show RPM at 1,500, and others only showing up to 3,000, etc There are various ways to fix this and I'll be giving them a go as well. When attaching the four coil wires to the -ve side of the coil, does it matter if it's right up close to the coils, or can it be hidden away at the other end of the wire, close to the EDIS? Why is nothing ever easy Quote Link to comment Share on other sites More sharing options...
Quagmire Posted October 10, 2017 Share Posted October 10, 2017 (edited) Hey Quattro - you'll get there! These things can be a right pain in the bum sometimes. The transistor legs will be arranged as below depending on how it is packaged: I don't think the wattage of the 1k resistor is critical at all - there should be next to no current going through it, and yes 0v is earth. I should say that it's worth leaving the relay intact at first, that way you can hear it buzzing as it is rapidly powered on and off. Then you know that your source of tach signal is at least doing something. Once you are happy that everything is working, you can cut the relay open and remove the contacts, leaving just the coil. Edited October 10, 2017 by Quagmire Quote Link to comment Share on other sites More sharing options...
quattro Posted October 10, 2017 Author Share Posted October 10, 2017 40 minutes ago, Quagmire said: I should say that it's worth leaving the relay intact at first, D'oh! Quote Link to comment Share on other sites More sharing options...
quattro Posted October 12, 2017 Author Share Posted October 12, 2017 As I already had the wiring for the tachfix, I have made up the board as per Quagmire's diagram. It can be made up to just plug in to the same wiring so much easier and neater then trying to splice into the coil pack wiring. Nothing, tacho doesn't even flicker. As the tachfix doesn't work, and this set up doesn't either, I really do have to suspect the wire added to the ECU. Tapping into the coil packs does work albeit only up to 1,300rpm, but there is something there. Is there anyone on here that can check out the ECU for me? Cheers Richard Quote Link to comment Share on other sites More sharing options...
garrycol Posted October 13, 2017 Share Posted October 13, 2017 Did I tell you that the wiring diagram I put up works . The wiring diagram comes from this device https://www.autosportlabs.com/product/tach-adapter/ For a 8 cylinder you use the complete circuit, for a 6 reduce by one cell and for a 4 only use half. Garry Quote Link to comment Share on other sites More sharing options...
quattro Posted October 13, 2017 Author Share Posted October 13, 2017 They all work Garry , but the one you have put up is of an unknown quantity, the others are from the Megasquirt manual. I will try it if all else fails, so thank you for posting it There does appear however, to be something wrong with the feed wire from the ECU, so I really have to find out what it is and fix it, as I don't want to bring my car home one day in a box donated by the fire brigade. My problem is that I bought the system from supplier A, who was so difficult to get hold of, and then when I did, didn't have an answer so I found another supplier from another forum to buy a tachfix box. So, supplier B didn't sell the tachfix box and put me onto supplier C who I did a load of testing for, then bought the box, and it didn't work. C then added a wire to the ECU which would gaurantee that the tacho would work - it didn't. Then work and life got in the way and I just the car back on the road with a tacho bouncing about like a demented grasshopper. Now, I have the car off the road again and have contacted C who said, "hmmm that's strange," and now doesn't answer emails. I asked supplier B if he could look at the ECU to check it's connected ok, and he has refused, saying that I should go back to A or C. So, my options are 1/. Keep pestering you chaps 2/. Find supplier D 3/. Go the uni and become an electronics expert 4/. Put up with not having a tacho 5/. Remove the wire myself and make up some fixes and try them all out on at a time - hoping nothing burny happens. 6/. Get a 14CUX and admit defeat Quote Link to comment Share on other sites More sharing options...
zardos Posted October 13, 2017 Share Posted October 13, 2017 (edited) Option 7 Get a tacho known to work with the IDM signal ? Option 8 Build a raspberry Pi dash to show Turner Studio gauges ? (I seem to remember somebody has done this here already) Edited October 13, 2017 by zardos Added option 8 Quote Link to comment Share on other sites More sharing options...
Quagmire Posted October 13, 2017 Share Posted October 13, 2017 Options 3, 4, 6 and 7 are not required - I also have a P6 like Quattro running MS2 and EDIS and my tach works fine with the relay method. These suppliers need to man up and support their client. Richard - in the meantime can you post up some pictures of both sides of your MS PCB? Then people on here can take a peek at what has been done modification wise and possibly advise. Quote Link to comment Share on other sites More sharing options...
quattro Posted October 13, 2017 Author Share Posted October 13, 2017 38 minutes ago, Quagmire said: I also have a P6 like Quattro running MS2 and EDIS and my tach works fine with the relay method. I am running MS1 with EDIS, but the MS1 Extra manual has the same diagrams, so it should work I'll pull the ECU in a mo and get some pictures over the weekend Cheers Q Quote Link to comment Share on other sites More sharing options...
quattro Posted October 13, 2017 Author Share Posted October 13, 2017 1 hour ago, zardos said: Option 7 Get a tacho known to work with the IDM signal ? Option 8 Build a raspberry Pi dash to show Turner Studio gauges ? (I seem to remember somebody has done this here already) Really want the dash to look the same as it does now - and I don't believe Rover did a tacho to suit the IDM Quote Link to comment Share on other sites More sharing options...
quattro Posted October 13, 2017 Author Share Posted October 13, 2017 5 hours ago, Quagmire said: Richard - in the meantime can you post up some pictures of both sides of your MS PCB? Then people on here can take a peek at what has been done modification wise and possibly advise. I really have no idea what to look for here, any ideas anyone? Quote Link to comment Share on other sites More sharing options...
Quagmire Posted October 14, 2017 Share Posted October 14, 2017 Ok so it looks like they have added it to use pin js3, where does the orange wire connect to, it looks like one of the spare output pins under the map sensor? Do your tach settings in Tunerstudio show js3 as the output pin? Quote Link to comment Share on other sites More sharing options...
quattro Posted October 14, 2017 Author Share Posted October 14, 2017 Tunerstudio is showing JS3 I am just making up a small wiring diagram for the circuit he has added. I only have a photo of the top of the original, but hopefully it will do Quote Link to comment Share on other sites More sharing options...
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