M104 HFM Swap in W201

[S70/2]

Alright, putting a 94 M104 into a 89 2.6 5spd W201 (Green/Black). Anyone with experience in HFM swaps care to shed some light as to exactly what I need to pull out of the donor 124? I've gotten the complete HFM/CC/ISC harnesses out, ready to harvest more. Going to add the flywheel magnet to a single mass M103 FW

I was really hoping this car would have a soy throttle body and harness but no, already replaced so no Megasquirt yet

Also, this new forum layout is freaking me out

 

[S70/2]

Forgot to mention this is also a non-ASR engine, the amount of wire harnesses and modules even on the simpler 6cyl is a bit staggering....I think adapting a BMW M50 motronic would probably be easier

 

[2phast]

Steve Geyer has done this swap with his 190E, he would be an excellent source for this. His forum name is SG Motorsports

 

[JC220]

A number of years back I had converted a manual 1987 W124 200 (4 cylinder carb engine) to a 3.6 HFM engine and auto trans.

I had transplanted all wiring and running gear from a non ASR W202 C36 AMG donor I bought complete. It was a rust bucket so ideal to take all the bits I needed from.

Initially do take some time and read through the thread link below. In there I had detailed the conversation and discussed the issues I had came across

https://www.google.co.uk/amp/s/www....d-td-class/2408521-e36-amg-project.html?amp=1

 

[S70/2]

Spent the better part of 5 hours yesterday pulling the body side HFM, ABS, ISC/CC, Diagnostic harnesses out, entire interior and dash needs to be removed. Once laid out it makes alot more sense, pretty straight forward with only a few mysteries. Going to use the entire 124 ABS harness and computer also...more photos and explanation to come for future reference

 

[Stevester 500E]

View attachment 80295

Spent the better part of 5 hours yesterday pulling the body side HFM, ABS, ISC/CC, Diagnostic harnesses out, entire interior and dash needs to be removed. Once laid out it makes alot more sense, pretty straight forward with only a few mysteries. Going to use the entire 124 ABS harness and computer also...more photos and explanation to come for future reference

Don't tear into the 190e yet, I would like to purchase it from you !

 

[S70/2]

Don't tear into the 190e yet, I would like to purchase it from you !

Not mine but I'll pass it along to the owner

Decided for good measure to remove the entire body harness from fuse box back....probably won't need much of anything from it but I'll always have correct color coded wires/connectors for future repair

 

[S70/2]

Ok got it all nearly wrapped up this past week, around 60 hours or so to turn key M104. Once all the wiring is laid out it is pretty simple to figure out. Picture time

One sad little 2.6






The complete HFM required wiring and late model ABS, W201 has fuel pumps on the driver side so I ended up just adding a single pole W124 connector to the existing harness next to the OVP rather than reusing W124 sub harnesss




Reuse M103 Starter harness, bracket even lines up on M104 filter housing


TDC Magnet added to single mass M103 flywheel


A little bit cleaner, most of w124 wiring added behind battery box









The W201 fuse box is kind of a pain to get the connectors off, I ended up using the some of the existing m103 harness and added an X26




Looking good and fired right up without even a CEL!

 

[captruff]

Very nice! well done!

 

[S70/2]

A few more things for anyone wanting to do the swap

Rubber custom length to replace plastic OEM hoses, temporary "Low emission" injection hose. I've had really bad longevity with CRP 8mm ID fuel hose only lasting around 6 months and completely dry rotting and leaking. Genuine BMW Part #: 16-12-1-180-409-BOE is the best option for this



W201 vs HFM 124 Throttle cables, must use HFM 124 as 201 and Jetronic 124 are both too short. Direct replacement



103 vs 104 thermostat housing, same but 103 already drilled and tapped for coolant return to expansion tank



124 ECU/OVP box fits pretty well





Definitely put the transmission onto the motor before installing together, because this thing is a damn tight fit in the 201 tunnel. I would without a doubt pull the motor and trans together for any service



Heater core and radiator connections are both identical, M103 vacuum hard line fits well, 124.104 PS Pump has larger fittings 201.103 is direct replacement just swap over rear mount bracket, late model 124 AC discharge lines up with condenser..suction just needs one crimp to combine 103 upper and 104 lower half

 

[R0BB09]

Hello S70/2, I’m new to this forum, well any forum in fact but I need a lot of help, I’m currently undertaking an m104 hfm swap, the motor is in and have managed to wire it to the extent where it turns, fuel pump responds to m104 fp relay but can’t seem to get it to spark, I’ve currently taken all the wirering back out to start again, I have full wirering diagrams printed out, one thing I’m confused with is how the ecu is supplied with power? If the fuel pump runs does this indicate power? I’m very glad I’ve discovered this thread as when I started the swap in January this wasn’t posted yet, I’m mechanically minded but new to cars and electrics in general, any pointer will be much appreciated, thanks!

 

[Stevester 500E]

what happened to S70/2??
I was enjoying this thread,

 

[S70/2]

The ol' girl has probably done around 8-10k trouble free miles since the swap, until the air pump bearing decided to retire and smoked the belt. Is there a cross reference for this or is the ebay special the best bet? Is removal and shorter belt fitting possible? Not needed anyhow

 

[S70/2]

Refurbishment of the world's lamest supercharger, found bearings on eBay for only $14..will see how long it lasts

 

[S70/2]

Still just enough clearance to get the top bolt out with radiator in place, the belt replacement is a pain but very doable. Smooth running once again...

In other news ive been screwing around with a few variations of a RUF boost controller knob in CAD with the 3d printer, the technology sure is crazy these days..

 

[TonyStark]

A few more things for anyone wanting to do the swap

Rubber custom length to replace plastic OEM hoses, temporary "Low emission" injection hose. I've had really bad longevity with CRP 8mm ID fuel hose only lasting around 6 months and completely dry rotting and leaking. Genuine BMW Part #: 16-12-1-180-409-BOE is the best option for this

View attachment 81708

W201 vs HFM 124 Throttle cables, must use HFM 124 as 201 and Jetronic 124 are both too short. Direct replacement

View attachment 81709

103 vs 104 thermostat housing, same but 103 already drilled and tapped for coolant return to expansion tank

View attachment 81710

124 ECU/OVP box fits pretty well

View attachment 81713



Definitely put the transmission onto the motor before installing together, because this thing is a damn tight fit in the 201 tunnel. I would without a doubt pull the motor and trans together for any service
View attachment 81714


Heater core and radiator connections are both identical, M103 vacuum hard line fits well, 124.104 PS Pump has larger fittings 201.103 is direct replacement just swap over rear mount bracket, late model 124 AC discharge lines up with condenser..suction just needs one crimp to combine 103 upper and 104 lower half

Hello, I am currently doing a SWAP of m104 on a W201 and I would like to know the box you put on your model? thank you