**help needed** m20b25 into 316i

Post Mon May 11, 2009 5:43 pm

post number 8 fpor my latest problems.

i should be picking up my new engine, gearbox, loom and ecu in a few weeks. its comeing with rad and bits like that. i know i will also need a new diff, prop and exhaust.

ive already got 325 suspension and front brakes on, got rear brakes waiting to be fitted.

anyhting else i will need?

also how do you go about registering it as a 2.5??

Post Mon May 11, 2009 5:53 pm

You need a 6 pot coding plug to make the clocks read right.

To register simply fill in the spaces on your V5 with new capacity and engine number, and send to DVLA.

Post Wed May 13, 2009 12:50 pm

can you give me some more details on this coding plug.

and anyone think of anything else i will need??

Post Sun May 24, 2009 8:25 am

quick question, do i need to change cross member/front subframe?

i was told by someone last night that i definately did.

ive just got this problem that my cambelt snapped yesterday so i have 2 days to do the conversion

Post Sun May 24, 2009 9:14 am

No need to change the cross member at all.

It's a good idea to get the 6 pot pas pipe from the pas tank to the pump as well, as the one from the 4 pot as it's a PITA trying to get the 4 pot one to the one on the 6 pot pump
If you can, get the metal section that the wiring sits in along the bulkhead to save trying to hide it behind the 4 pot plastic cover

Remember the oil cooler and pipework AND the 2 plastic brackets and spire clips to mount the cooler (you'll see the holes where the clips go on the front bracing bit).

Also the 325 header tank and pipe from the rad to header tank,and the plastic mount for it as well(will have to make 1 up to hold the bottom of the tank) and the bracket for the relay holder that normally mounts on the passenger side wing(assuming it's a low comp facelift lump that's going in)

I've probably forgotten some other little detail, but it's a start for now.

Post Sun May 24, 2009 9:34 am

no time to source extra parts, ive got he oil cooler and pipework.

are all facelifts low compression?

Post Sun May 24, 2009 9:39 am

yeah_mick wrote:
are all facelifts low compression?

Should be unless someones slotted an early hi comp sport lump in there.

Post Tue May 26, 2009 12:09 am

due to my unforseen circumstances ive had to jump into this without being fully prepared and ive run into a few problems.

do i need to change the fusebox?

ive also got a few wires/plugs that i dont know where they go, ive taken pics so hopefully someone can identift them for me.

here they go

this one comes off near the diagnostics plug, looks like the afm plug on the 316i afm, but her plug ont he afmi got with the engine is a rectangle?

these 2, one comes off the loom just after it comes out eh bulkhead and the other comes from thhe fusebox, i tihnk these 2 are positives for the battery?

and these 2 which look like they have previously been bolted together also come off the loom just after they come out the bulkhead.

and here is a pic of the ecu, these codes mean anthing to anyone? as there is a handwritten sticker on the other side of the ecu saying "e34 525i m20"

hope you guys can shed some light on this as im without a car and need it for work.

Post Tue May 26, 2009 12:15 am

yeah_mick wrote:
these 2, one comes off the loom just after it comes out eh bulkhead and the other comes from thhe fusebox, i tihnk these 2 are positives for the battery?

and these 2 which look like they have previously been bolted together also come off the loom just after they come out the bulkhead.

Those 2 look like power and earths to me.
I'll need to check which way round they go when i get back to the car.

I'll check the Ecu number while i'm there.
I'm pretty sure my one is a 173.

Post Tue May 26, 2009 12:18 am

any idea on the other round plug?

Post Tue May 26, 2009 12:21 am

Not at the moment.
I just removed the power and earth wires and left everything else attached(minus the ecu) when i lifted mine out. Same when it went back in.

I've got a couple of spare lumps with wiring still attached i can have a look at when i get over there tomorrow

Post Tue May 26, 2009 7:47 am

cheers mate, that will help alot if you can.

Post Tue May 26, 2009 9:02 pm

The 2 wires from the fusebox go to +12V at the battery
The 2 that come through the bulkhead go to the earth stud on the strut tower.

The round multipin connector goes under the inlet manifold. there should be a plug under there for it to connect to.It should be roughly in the middle of the block about 2 1/2" below the manifold,and there should be a metal bracket to hold the plug as well.

HTH

Post Tue May 26, 2009 10:49 pm

The ECU is from another M20B25 engine just from an E34. I blew my old one up!

Can't remember why I disconnected that round plug... Spastic moment?

Post Fri May 29, 2009 8:04 pm

all up and running now. bgi thank you to andyp for answering all my annoying phone calls and nelly for being utterly useless at getting my parts for me

when i came to start the car, i couldnt hear the pump prime and it wouldnt start, i pulled the hoses off and tried turning it over and no fuel came out, so i wired the pump direct to the battery to check i still worked and it squirted petrol everywhere so i knew ther pump worked. so i connected the fuel lines back up and tried starting it with the pump direct to the battery and it started within seconds. i just pulled a wire from the battery and obviously it cut out. so i plugged the pump back in properly and tried to start it and ever since its now been fine.

anyone got any ideas on why it done that? just cant get my head around how connecting it up direct to the battery seems to have kicked it into life