Quick Q on ECU no's M40 engine

[soul4t]

Hi,

I was reading the Motronic section on the wiki and noticed 2 numbers for the 316i M40 engine:

http://www.e30zone.net/e30zonewiki/index.php/Motronic

Could anyone tell me the difference? If there is one?

Thanks

[TPS]

Is one a Cat. version?

[soul4t]

Hmm,

I did think that, but I think my 174 one is cat compatible...not sure though!

[Billwill]

What does realoem.com say about the part numbers?

[magpie]

i've got a few ecu's here that are from m40's with cat's fitted .

http://www.ebay.co.uk/itm/bmw-e30-316i- ... 27cca540e5

[soul4t]

Just checked the ECU's on my (07/1990) car and the latest model (04/1991), both have the same number...also, when checking for lots of parts, there have been 2 part numbers...exhaust specifically, Cat or No Cat, so I guess it's not different because of Cat fitment.

@magpie, I might take a chance and buy one from you, then see if it works...I know there's a grey/black wire that needs to be plugged in to ensure the ECU knows that a Cat isn't fitted (probably goes to an O2 sensor when fitted), so unless anyone knows why it shouldn't work!

[jmc330i]

^^ The wire I think is to connect the CO2 adjustment pot. You need to connect the pot if you're removing the lambda sensor.
The 'cat' ecu in my '93 318i runs fine without the lambda fitted, I connected the wire under the bulkhead wiring cover and as the AFM doesn't have the co2 pot I needed to fit a non-cat AFM.

I'm not sure if a non-cat ECU will work on cat/lambda equipped car.

[soul4t]

Cool, thanks for the input...do you have an M42 engine fitted? If it's anM40, do yoi know what ecu no. It is?
Ta

[jmc330i]

Its an M40. If I get chance tomorrow and its not pissing down, I'll pop the ECU out and check the numbers.

I've got an '89 non-cat ECU here somewhere, I'll try and find that one as well for the numbers.

[soul4t]

Nice one mate! Hope the weather's good then!

[jmc330i]

Sorry for the delay chap... Both ECUs, from the 1989 and 1993 318i have the same number, 0 261 200 387.

So when I said the '89 ECU was non-cat, it seems its cat ready and should work fine in a later car.

[soul4t]

Cool,

No worries about the delay...yep looks like the cat's not the reason then!

Cheers!

[soul4t]

Right,

I think I've got it, I found an ecu on ebay ending 989, popped in the bmw part number in realoem and it came up with touring models. It's price is a couple of hundred pounds more as well!?

So what could be the differences? Imoboliser or something? (clearly stabbing in the dark!)

It seems to feature in both manual and auto cars. (As does the 174 ecu)

I wonder!

[Brianmoooore]

Late M40 ECUs fitted to E30s were fitted with EWS 1.

[Andyboy]

Late M40 ECUs fitted to E30s were fitted with EWS 1.

Not sure about that. EWS 1, iirc, needs a general module to tell the ECU if the car is locked or unlocked and E30's never had one. EWS1 was a refined version of drive away protection where there are high and low signals from the general module to detect if the car is locked, deadlocked or unlocked and prevent the car from starting via a signal from the GM to the starter interrupt relay and ECU.
E36's and E34's had EWS1 from Jan 1994 but I don't recall E30's having it. The ECU was replaced with a modified version in June 1994 to recieve a direct signal from the starter interrupt relay.
The last E30 Tourings were built in Jan/Feb 1994 so didn't get it. There are however different E36 M40 and M42 ECU part numbers.

Edit: According to the BMW tech bulletin, the E30 and E32 models were not fitted with EWS1, probably because both models were discontinued in Feb - March 1994.

[Brianmoooore]

Late M40 ECUs fitted to E30s were fitted with EWS 1.

Not sure about that. EWS 1, iirc, needs a general module to tell the ECU if the car is locked or unlocked and E30's never had one. EWS1 was a refined version of drive away protection where there are high and low signals from the general module to detect if the car is locked, deadlocked or unlocked and prevent the car from starting via a signal from the GM to the starter interrupt relay and ECU.
E36's and E34's had EWS1 from Jan 1994 but I don't recall E30's having it. The ECU was replaced with a modified version in June 1994 to recieve a direct signal from the starter interrupt relay.
The last E30 Tourings were built in Jan/Feb 1994 so didn't get it. There are however different E36 M40 and M42 ECU part numbers.

Edit: According to the BMW tech bulletin, the E30 and E32 models were not fitted with EWS1, probably because both models were discontinued in Feb - March 1994.

Read what I wrote! The ECUs were fitted with EWS - not the cars. AFAIK, BMW never made use of the facility in the E30, but I've come across one aftermarket immobiliser where it was connected up, which is why and how I'm aware of it. An extra wire is connected to the ECU plug (grey/red or red/grey IIRC) to a pin somewhere near the middle of the plug, but I've never discovered where the other end of this wire is.

[Andyboy]

Read what I wrote! The ECUs were fitted with EWS - not the cars.

So, if the ECU has EWS and the car doesn't, how does the car start?

Answer - it won't, but the M40 ECU's were NEVER fitted with EWS.........that would be EWS11 from January 1995. What you may have found is drive away protection or some non factory set up.

The first ECU's to actually read a signal from the starter interrupt relay were introduced in June 1994, several months after the E30 left production and - would you credit it - to coincide with the launch of the M43 engine. How about that?

But to actually answer the OP: The non cat version (102 bhp) is the regular 174 ECU and the catalyst cersion with 100 bhp has the 989. It's calibrated to run leaner and thus with a hotter exhaust.

[Brianmoooore]

EWS 1 ECU just looks for a simple high/low DC signal. No digital code that has to be aligned with a control module like with EWS 2 and onwards, so as long as the appropriate DC level is always present on the ECU pin, why wouldn't it start and run.
The immobiliser on the one I found with a connection to the additional loom wire was an aftermarket one, but I've also found the same extra wire on a couple of other late tourings. Both of these had factory immobilisers, but these were just connected to break the engine loom switched ignition live, as on earlier E30s.

[eko]

I have an `989` Orange label ECU from a good running car if needed

[Andyboy]

The factory immobiliser on the pre 1/94E36, E34 and E31 is Drive Away Protection, NOT EWS1.
DAP was fitted from September 1993, so very late cars only. DAP works by giving a signal to the DME unit - the very same signal and circuit that the OBC uses to immobilise the car.

EWS 1 is different. It uses a starter immobiliser relay, and is linked in with the transmission selector on autos and the OBC as before. The relay needs inputs from the ignition switch, the OBC, engine ECU and the gear selector on autos, and it gives output back to the starter motor and engine ECU.
EWS1 was not fitted to E30's because the E30 doesn't have a general module like the E36 and E34. Therefore it cannot interpret high and low signals from the door locks to tell the ECU if the car is locked or not.

The alarms are dealer fit and most are the 3T type which have connections into the car loom for the fuel pump and starter motor.

Anyway, I'm off down the pub.

[eko]

Mines from a March 1994 Touring BTW

[soul4t]

Interesting conversation guys!

@eko, thanks mate, but I think I ought to stick to the 174 if what Andyboy says is true, I would like to get a guaranteed working ECU...which could be alot to ask for, but one from a well running car is probably the best I can hope for.

My problem appears to be fuel/temp/ICV signal related, all obviously checked out component and wiring wise, so I am eliminating any faulty processing from the ECU, I need to rule it out I believe to continue my efforts to resolve my problem. (http://www.e30zone.net/modules.php?name ... highlight=) if you have the patience to read.

Thanks for the input all!

[magpie]

fookin amazing battle of the multi meters

[eko]

I should add that the ECU I have originally came from my 94 Touring.
I removed the M40 engine around 2 years ago in favour of an M52.
My old M40 engine and ECU then went into a G reg(1990) 318i.
No changes were made to any keys etc to make it run,just a simple plug and play M40 swap....certainly no signs of any factory immobiliser/EWS.

[Andyboy]

Proper immobilisation started with EWS11 in 1995. Before that you could swap ECU's at will. DAP & EWS1 were just slowing a thief down.

[markus_74]

hello, soul4t

mine ecu was 0261200157, it for 1991 M40 318i
mine is non cat and fit with co adjustment afm, 028020203

hope this help
Markus

[soul4t]

Hmm, interesting...

lets not stab in the dark at what it could be...

Continue your thread and we'll see what your investigations dig up, I'm pretty much out of ideas on mine!