BillyW124
MB Enthusiast
- Joined
- Oct 22, 2010
- Messages
- 2,891
- Location
- North West London
- Car
- W124 E320 coupe, W211 E320 V6 CDI, W211 E63 V8 AMG, R129 SL 280 V6, W215 CL 600 V12 Bi Turbo.
Hello Chaps,
After much umming, arring and mind changing over the last year or so I’ve been toying with the idea to ditch my perfectly running no – nonsense, exactly what it says on the tin 2.2 M111 swapping it for a 3.2 M104.
The 4 pot has served me well up until now and I expect the 6 pot to serve me better. I have no doubts that it will. Would it have been easier and cheaper to have gone out, sold my current car and bought a 320 Coupe – yes. Would it have given me the same fulfillment – No. Besides, I’ve done quite a bit of work on the coupe already to let it go like that.
The M104 will also give me better options available to me in terms of performance upgrades down the line should I consider something like it!? For now though, I’ll be a happy chappy with an unmodified straight six.
So, the engine conversion marks the start of various mods that I have been planning since I’ve owned my coupe. This includes exterior stuff, interior mods and a few other things up its sleeve.
In fact in all honesty an engine mod was last on my list!
The M104 320 lump for the conversion is from an early 1993 320E with just 99k on the clock. Although there's not a huge difference between an early 320 and an M104 from a 1995, I believe the stand out differences between the two engines are the early ones maybe are a little less ‘electronically’ managed than the later ones. Also the donor car came with no A/C which would help things along as my coupe hasn’t got it either.
The donor car I bought was spotted out of chance trawling through the net at a cheap price. The engine has a solid history which has been well maintained with the dreaded wiring loom and head gasket being replaced, all of which is documented In the service pouch. It did have its issue as advertised with an intermittent cutting out problem hence the price. The engine would fire up then cut out when it wanted to. The owner from who I bought it off had intentions to fix it but he had two other lovely merc’s and didn’t have the time to mess around with this one. Knowing this intermittent cut out issue I still bought it….after all how hard could it be fault finding it?
Dropped the car to Simon (Carat 3.6) one Sunday evening on the back of the trailer and promised me that we’ll have her up and running. Getting it up and running he did indeed. We both suspected the fault to be a possible fuel pump relay issue. This wasn’t the case, then we hoped it to be the OVP relay among the other likely causes. It wasn’t these either. Moved on to ECU diagnosis. At this time I was beginning to touch cloth…
Turns out the ECU had been opened up and repaired previously more than once! However the company who repaired the thing had no info on what they actually had done to it. So had the ECU tested and was all clear but it read 76 faults! Being the nut case I am, I kindly asked Simon to do away with this piece of junk and I got on the case for a replacement pronto. There was no way I’m having a bodged up ECU even if repaired (again) that there was a slight chance of it messing up in the future. Besides I want my 6cyl M104 experience to be blissful not hampered. I got the ECU sourced from the good chaps @ German SPOB and guess what….The car still cut out!
Not all bad though, this ECU actually read what the fault was which the old one didn’t. We think that the old de-grading loom sparked something in the ignition circuit causing the cutting out problem. (I suspect this is why the loom was changed by the owner before the chap I bought it off in the first place) A bit of soldering and by passing (?) later the engine is running sweet with no issues. I’m sure Simon can elaborate more on the fix then I can! All I know is that I’ve got an ECU that works and an engine that doesn’t cut out!
...Roll on the conversion.
After much umming, arring and mind changing over the last year or so I’ve been toying with the idea to ditch my perfectly running no – nonsense, exactly what it says on the tin 2.2 M111 swapping it for a 3.2 M104.
The 4 pot has served me well up until now and I expect the 6 pot to serve me better. I have no doubts that it will. Would it have been easier and cheaper to have gone out, sold my current car and bought a 320 Coupe – yes. Would it have given me the same fulfillment – No. Besides, I’ve done quite a bit of work on the coupe already to let it go like that.
The M104 will also give me better options available to me in terms of performance upgrades down the line should I consider something like it!? For now though, I’ll be a happy chappy with an unmodified straight six.
So, the engine conversion marks the start of various mods that I have been planning since I’ve owned my coupe. This includes exterior stuff, interior mods and a few other things up its sleeve.
In fact in all honesty an engine mod was last on my list!
The M104 320 lump for the conversion is from an early 1993 320E with just 99k on the clock. Although there's not a huge difference between an early 320 and an M104 from a 1995, I believe the stand out differences between the two engines are the early ones maybe are a little less ‘electronically’ managed than the later ones. Also the donor car came with no A/C which would help things along as my coupe hasn’t got it either.
The donor car I bought was spotted out of chance trawling through the net at a cheap price. The engine has a solid history which has been well maintained with the dreaded wiring loom and head gasket being replaced, all of which is documented In the service pouch. It did have its issue as advertised with an intermittent cutting out problem hence the price. The engine would fire up then cut out when it wanted to. The owner from who I bought it off had intentions to fix it but he had two other lovely merc’s and didn’t have the time to mess around with this one. Knowing this intermittent cut out issue I still bought it….after all how hard could it be fault finding it?
Dropped the car to Simon (Carat 3.6) one Sunday evening on the back of the trailer and promised me that we’ll have her up and running. Getting it up and running he did indeed. We both suspected the fault to be a possible fuel pump relay issue. This wasn’t the case, then we hoped it to be the OVP relay among the other likely causes. It wasn’t these either. Moved on to ECU diagnosis. At this time I was beginning to touch cloth…
Turns out the ECU had been opened up and repaired previously more than once! However the company who repaired the thing had no info on what they actually had done to it. So had the ECU tested and was all clear but it read 76 faults! Being the nut case I am, I kindly asked Simon to do away with this piece of junk and I got on the case for a replacement pronto. There was no way I’m having a bodged up ECU even if repaired (again) that there was a slight chance of it messing up in the future. Besides I want my 6cyl M104 experience to be blissful not hampered. I got the ECU sourced from the good chaps @ German SPOB and guess what….The car still cut out!
Not all bad though, this ECU actually read what the fault was which the old one didn’t. We think that the old de-grading loom sparked something in the ignition circuit causing the cutting out problem. (I suspect this is why the loom was changed by the owner before the chap I bought it off in the first place) A bit of soldering and by passing (?) later the engine is running sweet with no issues. I’m sure Simon can elaborate more on the fix then I can! All I know is that I’ve got an ECU that works and an engine that doesn’t cut out!
...Roll on the conversion.
Last edited:
not the most reliable systems but before i took it out of a donor i know it worked!
