Dammit have I got the right ECU here? El Dyno eet say YES :)

[blue30]

Hay yall,

Just been for the first little cruise in my newly M50b25'd 320i. All went well, it just, er, felt a bit slow

I wasn't giving it major beans and it has only got 1/2 an exhaust but still, I expected it to feel a bit more torquey and willing than it does.

It runs smoothly, idles smoothly except it idles at 500rpm...

One thing - the guy who sold me the engine & ECU gave me two ECU's, cause he said he thought one was for a m50b20 but couldn't remember which one. I tried both and they run roughly the same.

Google gives conflicting answers, some pages list both as being for an m50b20 and some list them both as being b25

The one pictured says 0 261 200 405 on the big label, the other one says 0 261 200 403. The top of the 403 one appears to have been brillo-padded and one of the torx bolt heads is sheared off...



Any thoughts?

Many thanks kind peoples!!

Neil
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[Cook318IS]

I have a "405" ecu in my m50'd e30. the 405 ecu will be a b25 one.

[E30BeemerLad]

I've got a spare red label 402 ECU here, my M50 came from an E34 525, not sure if this is different to the ECU from the E36.

That 402 ECU was for a non-vanos lump

[glenn]

the ecu in the picture is from......
e34 saloon
525i
prod date 06/1991
m50 rhd with manual transmission.

if you enter the last seven digits of the chassis number on the realoem site, it will give you this information.

[blue30]

Ah, simples! The WBA.. number is the chassis number then? Many thanks, looks like im on the right track with that one. Will leave that one in and troubleshoot from there.

I dare say I'll be back in a week or so with more stupid questions

[daimlerman]

M50 does seem to lack torque low down,I find that I need to keep it above 2000rpm all the time,and be prepared to go above 4000rpm to find the real grunt.
What gearbox/diff combo are you running?

[blue30]

The blue streak is off getting its zaust done today so will be able to give it some more beanage soon, not taken it over about 5K yet and I've been driving it with eggshells under the throttle while the zaust was so loud.

Thats the other thing, I'm running an M40 box with a 3.05 diff - intergalactic-tastic! But I was running this diff for 10 months or so on the m20b20 and was pretty used to it. You have to use the gears differently but overall I preferred it to the way the car was before. It suited the cruise-y character of the car. But I've been hairing round in a little short geared hot hatch while the e30s been in surgery so maybe I just need to get used to the lazier delivery again. Either that or drop the 4.1 back in again

[daimlerman]

I found that a 3.45 was too high,spending all my time in fourth off the motorway,with no significant gain in economy.
I now have a 3.64,find it very much better for all circumstances and last week the thing returned 33mpg!
A lot of zoners are using even lower ratios,3.91 seems a popular choice,would certainly make the grunt more 'available' in the top three gears but seems to render 1st redundant.

[blue30]

Yeah it was the first gear thing around town that used to piss me off, with this thing on first pulls round to 30 odd which is lovely when you're just nipping about the place, 4th is allmost exactly where 5th used to be. I'll pick a 3.64 up when I've got some more cash to spend and give it a whirl!

Got the zaust sorted today and gave it a bit more beanage, I think the power is there its just the smoother delivery and the uuber long diff thats making it feel slower than it is. You kind of pick up speed so smoothly that you don't realise you're doing it. Its a lot smoother than the M20 was.

The zaust is the thing I'm least happy with really, I bought a pre-modded m3 manifold and a custom stainless system from someone breaking a conversion on the bay and allthough its got me on the road after a bit of re-working I wish I'd spent a tiny bit more and got something that looked and sounded a bit less council. Will definitely get it re-done when I've got the dollar.

Anyone wanna buy an M20b20?

[daimlerman]

Exhaust manifold was a major issue for me,I had several attempts at making one,then a huge income tax rebate arrived,so I 'phoned Fritzbits!
Combined with a stock GSF centre and rear section,it is quiet when cruising and a pleasant roar when sending instructions for more power!

[Cook318IS]

Ive heard an m52 with the full fritzs s50 stainless exhaust system. It sounds immense - im definately going to invest in one for my m50!

[blue30]

So many different ways of doing things! One thing I did which most people don't seem to is keep the e36 flywheel and cluch with the m40 box - it seems to work quite well, is the m20 one just lighter?

Oh and I had that thing where the clio server clunked half way through its travel that a lot of people posted about - but after driving round with it as normal for a mile or two that just disappeared. It only did the clunk before it had had vacuum on it in-situ, if that makes sense...

[Cook318IS]

So many different ways of doing things! One thing I did which most people don't seem to is keep the e36 flywheel and cluch with the m40 box - it seems to work quite well, is the m20 one just lighter?

correct, the m20 one is lighter.

[blue30]

OK, slight update!

I've been running around in it for a week now and allthough it runs quite well I'm sure theres something not quite right with it, when you tip the throttle in it feels a bit weak and hesitant. It never misfires or anything but you can feel the torque coming and going a little bit and the enegine note getting fluffy, as if the fuel pump was weak but then if you pull round to 6K it does pull quite well which kind of rules that out I think.

Anyway I got the MAF with the engine, in the same box 'o' bits as the two ECU's cause he couldnt remember which was for a 2.0, and I've just googled the part number on it and it comes back on some sites as for a 750/850 and on some as for 2.0 e34... real OEM can't find a match for the number and it certainly doesn't match any of the cars I looked up with an m50b25NV.

The magic number is 0 280 212 010, does anyone know anything about it??

Many thanks again!!

[E30BeemerLad]

your symptoms do sound quite similar to what my M52 was doing when the cam sensor was shagged. It had not much bottom end shove and although it would rev around to the redline, it was a bit sluggish getting there and you did feel it surge occasionally and give a little bit more and then die out again

Trouble is, it's an expensive day out oif it doesn't cure your problem at £75 from BMW for a new sensor. Not worth buying a £30 aftermarket one.

[blue30]

Cheers
I definitely think that I've got the wrong MAF here, I looked up what it should be to match the details from the ECU chassis number and they are the same for e36 and e34 NV's, and mine aint that one!! I think its probably off a 520. So I'm going to get another MAF and see where I am then, then I'll look at the cam sensor... dammit, thats what you get for buying a box 'o' bits rather than a running car

[E30BeemerLad]

yep, been there, done that

[daimlerman]

I think I have a spare M50 MAF in my treasure store...I bought a second one to eliminate poor running on my car,turned out to be a poor engine earth...let me know if you want it!

[DanThe]

A 2.0 litre engines inlet boot is smaller in diameter than a 2.5, same goes for the MAF and throttle body

That number you posted is the Bosch part number

[blue30]

A 2.0 litre engines inlet boot is smaller in diameter than a 2.5, same goes for the MAF and throttle body

That number you posted is the Bosch part number

Cheers
Theres a number underneath that one that should be the BMW number but it comes up with nothing on real OEM or google Googling the Bosch number brings back loads of stuff about 850i's, and the odd bit about 520's... i'm pretty sure in my mind now what maf I need, gonna try and find one on saturday!!

Daimlerman cheers for the offer, i'm in super-impatient mode at the moment trying to get it sorted asap so will try and source one locally first but if I can't I'll PM you!

[mick_318is]

Don't want to scare you.

Reading through your problems I noticed is that in your "box of bits" you seem to have a lot of M50B20 parts.

Did you but the engine from a reliable source?

Don't know a great deal about the M50 engines, though I have read before that someone was sold a M50B20 instead of a M50B25 and it was hard to tell the difference.

[blue30]

Cheers will look into the 2.0 thing, feels a bit strong for a 2.0 though.

Major drama last night, picture a sodium lit car park in the middle of market drayton at about midnight, with me huddled against the freezing cold in my finest lady friendly clothes as I climb aboard the e30 and thumb the ignition. The odd pack of drunks stagger here and there as the mighty m50 fires up, I aim the bonnet over at the car park exit, and rumble forwards. The dark, empty roads of shropshire bekon.

Just imagine my disappointment, angst and inner turmoil then when I glance down before leaving the car park and notice that the oil pressure light has come back on again. fffuuuuuuuuuu..... I've sold my runabout too

Having killed it again and ascertained that there was actualy some oil in the thing I tried it again, same result. But the light was weird and flickery, kind of 1/2 on and didn't respond to revs. The engine sounded perfect if a little rough cause of the MAF thing.

So I took an executive descisionm, tucked my balls in and went for it. I just drove it 20 odd miles home like that, no drama, no noises. Spend half the night lying awake stressing, going over in my head when I did the oil pickup, was the gasket on right, did I torque the bolts properly, could it be the sender, etc. etc. etc.

Anyway long story short it was the sender! I put the one off the M20 on and its fixed it. I spent the day giving the old girl some good lovin, cleaned up all the grounds, re grounded the ECU, put an extra ground on the engine, rotated the MAF so it was sitting up straight rather than canted over, swapped the heater hoses round so the heater actualy works. Swapped the rad for one that doesn't leak, replaced the missing front lip, washed it for the first time in months and some part of that lot has made the engine really wake up - the uneven-ness and un-willing ness has almost completely gone now. The idle's still a touch low but its much steadier now.

Having spent the day messing around with that lot I ended up not getting another maf. Still wanna try one though.

Daimlerman!! Still wanna sell me that MAF? Is it a non-vanos one? I tried a vanos maf that I picked up locally on friday night but sadly its only got 4 pins, mine's got 6 on it....


Cheers for the help so far all

[hongkongfuey]

just as reference, i have got the ecu out of my old 325 non vanos e36, the number is 0 261 200 403, green lable

[blue30]

Just thought I'd tag this on for info - I got rolling roaded today at Mikeanics in Congleton. The current spec is 2.5 non-vanos, modded M3 manifolds currently blowing at the flexi, custom front pipes into standard new egay special 3-piece 325i system. Halfords special cone filter intake, & the ECU as above:






Thats a flywheel figure, I didn't get a print of the wheels figures but I saw it heading up around the 180 as he was doing the run

It was part of a group day and when it came to mine he didn't look under the bonnet and I didn't actually tell the bloke that it wasn't a 320i, as I wanted the rollers to do the talking kind of thing. Allthough I think he figured it out pretty quick when he started the runs lol. I mention that cause otherwise I thought it might look a bit suss getting the exact stock figure for that engine

[Speedtouch]

Congratulations! It could, of course, be further improved with an m50B25 non-VANOS chip

[Cook318IS]

Thats not bad! my non vanos only made 183bhp but with a TINY induction kit. its got a halfords special one back on too

I think i may need to invest in a speedtouch chip soon...

[blue30]

Congratulations! It could, of course, be further improved with an m50B25 non-VANOS chip

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