Ke70 Tacho Dash Not Workin With 6 Cylinder

[KE70+AE92]

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

 

 

[oh what a nissan feeling!]

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.

[pozman]

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

[oh what a nissan feeling!]

Interesting, please find that link if you can. would be interesting to know what revs I'm doing at 110kph.

[KE70+AE92]

  On 11/5/2011 at 12:41 PM, pozman said:

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

[pozman]

yeah ill have a hunt for it

 

some have a big enough trim pot in them, mine didnt

[pozman]

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

[KE70+AE92]

Thanks for that ill measure the resistance of the original one and go from there

[KE70+AE92]

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