Need help with wiring BMW Tacho to 1JZ

[Dispatcher]

Good day all, I have my BMW E34 just converted to a 1JZ.
Have everything working except for the Tacho. Is this due to the signal being different and some kinda converter is needed ? Like converting Analog to Digital or Vice-Versa ?

Thank you
Dom

[kewp]

I had this problem when I did my sr20 e30 conversion, the sr ecu outputs a 5V tacho signal, it needs to be converted to 12V for the bmw tacho to read it. This is the circuit I used to convert the voltage. So if the 1J ecu outputs a 5V signal then you can use the same circuit.

Great conversion by the way!

[Dispatcher]

hi Kewp, great info thanks. What did you use to 'boost' up the signal to 12V ?

I like this conversion too, it's a great combo IMO.

Cheers
Dom

[lexsmaz]

Hi Dom,

Any chance of some pic's of the conversion, as it sounds like it would be a good thing ..

It looks like kewp boosted up the voltage to the Tacho via the 12 volt supply coming through the Diode, then onto the transistor which is triggered by the output from the ecu tacho wire & then the 12 volt signal is sent up to the Tacho .. ( he's obviously a bright cookie )

[kewp]

There is no diode, just a transistor and 2 resistor, u don't really need to understand how that circuit works if u don't want to, just build it and I think it will work for u

[Dispatcher]

Thanks mates. Any idea what transistor and diode I'd need to use?

Pics as requested.

Cheers
Dom

[Dispatcher]

More pics, I'll get a photo hosting site uploaded so anyone can
view the pics

Cheers
Dom

[kewp]

Look at the circuit picture I uploaded, there is no diode. It shows all the components u need

[Dispatcher]

Kewp, did as per your diagram, it did not work. I'm thinking the 1JZ is throwing out something larger than 5V.

Any ideas ?

Cheers
Dom