KE70+AE92 Posted November 5, 2011 Report Share Posted November 5, 2011 hey all I'm half way throught my commodore v6 t5 conversion in a ke70 and I'm havin problems with the tacho dash i purchesed this cluster last week and installed it today. i wanted to keep the same cluster for the conversion, ive got all the alt and oil lights and temperture gauge working so far but the tacho has left me stumped i no ive wired it up correctly but the needle on the tacho wont budge. i no its got a different signal to the original 4 cylinder but atleast the needle should move but be out ive tryed adjusting the trimpot on the back of the gauge but no luck. i did test the gauge by using a 12v charger and it did work I'm so confused why it wont work if anyone has some suggestions let us no they will be greatly appreciated Quote Link to comment Share on other sites More sharing options...
oh what a nissan feeling! Posted November 5, 2011 Report Share Posted November 5, 2011 Hi, I have actually had the same little drama with my vx powered pajero, hooked the feed from the ecu to the tacho but it has never worked. I have not been bothered to look into it, just figured it must use a different signal or something. but just so you know youre not alone. Quote Link to comment Share on other sites More sharing options...
pozman Posted November 5, 2011 Report Share Posted November 5, 2011 i had the same issue when i did the 7mgte conversion in my bundera basically the tacho in the ke70 is set up for high voltage/output pulse signal, coming directly from the coil the tacho signal coming from the v6 comes from the ecu, is lower voltage/output which means the signal isn't powerful enough to be read by your tacho there is a way around it, there is a resister inside the tacho that has quite high resistance, you need to replace this with a lower resistance one, the resister is not hard to find, its the first one in the board coming from the signal wire i can't remember the ohms of the resister i put in, ill see if i can dig up the info theres also the issue of the tacho will be reading wrong, it will be getting 3 pulses for every rpm now instead of two, this means the rpms will read higher than actually are this can be fixed by putting a potentiometer between the two wires that come out of the board to the needle, the +ve and -ve, you will then be able to adjust it to give the right reading i hope this has made sense, ill try dig up the link, it has pics and stuff, it was for a hilux but should be similar paul Quote Link to comment Share on other sites More sharing options...
oh what a nissan feeling! Posted November 6, 2011 Report Share Posted November 6, 2011 Interesting, please find that link if you can. would be interesting to know what revs I'm doing at 110kph. Quote Link to comment Share on other sites More sharing options...
KE70+AE92 Posted November 6, 2011 Author Report Share Posted November 6, 2011 i had the same issue when i did the 7mgte conversion in my bundera basically the tacho in the ke70 is set up for high voltage/output pulse signal, coming directly from the coil the tacho signal coming from the v6 comes from the ecu, is lower voltage/output which means the signal isn't powerful enough to be read by your tacho there is a way around it, there is a resister inside the tacho that has quite high resistance, you need to replace this with a lower resistance one, the resister is not hard to find, its the first one in the board coming from the signal wire i can't remember the ohms of the resister i put in, ill see if i can dig up the info theres also the issue of the tacho will be reading wrong, it will be getting 3 pulses for every rpm now instead of two, this means the rpms will read higher than actually are this can be fixed by putting a potentiometer between the two wires that come out of the board to the needle, the +ve and -ve, you will then be able to adjust it to give the right reading i hope this has made sense, ill try dig up the link, it has pics and stuff, it was for a hilux but should be similar paul that helps alot thankyou ill have a look at the size of the resistor and see what i can replace it with with the incorrect signal, ino when i had the 12v charger connected to the tacho to test the original trimpot could change the reading a whole 2000rpm but may not be enought Quote Link to comment Share on other sites More sharing options...
pozman Posted November 6, 2011 Report Share Posted November 6, 2011 yeah ill have a hunt for it some have a big enough trim pot in them, mine didnt Quote Link to comment Share on other sites More sharing options...
pozman Posted November 6, 2011 Report Share Posted November 6, 2011 (edited) took me a while but found it, obviously not going to be exactly the same as the ke70, but will give you enough to go off http://www.mindspring.com/~jayk3/toyota/tachmod.htm paul edit, maybe thats not it, but found another site that said the new resister should be around 10k ohms http://i6.photobucket.com/albums/y242/1Thsalvermo/Truck%20pics/Tach-fix-resistor-installed.jpg Edited November 6, 2011 by pozman Quote Link to comment Share on other sites More sharing options...
KE70+AE92 Posted November 6, 2011 Author Report Share Posted November 6, 2011 Thanks for that ill measure the resistance of the original one and go from there Quote Link to comment Share on other sites More sharing options...
KE70+AE92 Posted November 10, 2011 Author Report Share Posted November 10, 2011 hey after a bit of muckin around with resistors i got it working with a 1k0 resistor, the original one was a 39k so it was a big drop but it seems to work really good i just gotta get a digital tacho now to set it thank for everyones help Quote Link to comment Share on other sites More sharing options...
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