M20B25 post conversion niggles

[kaypee]

Hi all,

I have recently fitted an M20B25 to my old 1989 318is.

Engine is in and runs perfectly but has a few minor niggles id like to iron out.

The speedo seems to be reading right but the rev counter is having a right spaz and thinks its revving round to 10K rpm. Any ideas on the cause of this? Where does the signal for the rpm get taken from?

Thanks

kp

[Scruffymurphy]

Did you change the plug in at the front of the clocks for a 6 cylinder one?

[m_jermyn]

Yup you have not changed the coding plug, it located at the front beneath the taco or on old clusters its at the back of the taca..

[kaypee]

Many thanks, swapped the coding plug over tonight and the tacho now reads as it should!

What is the difference if any between the 318is diff and a standard 325 diff (non lsd)?

Do i NEED to swap them over or will the 318is diff cope?

[Scruffymurphy]

It should cope ok. The 318is diff will be a small case and a 4.10 ratio so it won't be as strong and it will rev a bit higher than if you had the medium 3.91 diff from a 325.

[333i]

but accelleration will be awsom

[kaypee]

Yeah, the casing is different between the two which is why i asked ... The donor 325 diff looks like its seen better days and my original 318is diff looks mint in comparison so its one part i would prefer not to change over unless it was 100% essential. Just need to swap over the front springs to eliminate a little of the front end nosedive under braking and i believe its ready for an MOT and going back on the road.

The car itself has been in the family from brand new and carrys alot of good memories with it. I was devestated when i heard that the M42 died so i took it upon myself to bring it back to life

Thanks for the help guys.