Motronic 079 and 059 Differences

Specific conversations and info for the BMW E28 M5 and M535i.
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robertodonnell
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Motronic 079 and 059 Differences

Post by robertodonnell »

Hi team,

I have an S38b35 converted M535i, but it seems that the "converter" used the M535i ECU.

I have an 059 ECU, instead of what I believe should be an 079? Anyway, the car runs pretty good, and I wouldn't have known except that I pulled the ECU to amuse myself.

Does anyone know what the actual differences of the 2 systems are? I don't know if the 059 loom was cut and shut to fit the S38, or the S38 loom was cut and shut to fit the 079.

Should I be sourcing an 079?

Cheers,

Robert
Syndrome
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Re: Motronic 079 and 059 Differences

Post by Syndrome »

Good question. I don’t know the answer, but am curious whether the 079 can be moved from one car to another without programming the recipient car’s VIN into it. Does anyone know? Thanks.
Galahad
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Re: Motronic 079 and 059 Differences

Post by Galahad »

Syndrome wrote: Jul 23, 2022 10:34 AM Good question. I don’t know the answer, but am curious whether the 079 can be moved from one car to another without programming the recipient car’s VIN into it. Does anyone know? Thanks.
The ECUs have no idea what a VIN is, let alone what your's is "supposed" to be. You can swap ECUs around as long as you match the part number (it may even be less restrictive than that).
austin8753
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Re: Motronic 079 and 059 Differences

Post by austin8753 »

the improper controller will make the engine run improperly. i would install an 079 for the S38B35, for sure.
///M
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Re: Motronic 079 and 059 Differences

Post by ///M »

I am not surprised that you did not notice from driving the car. When I first swapped the "incorrect system" it was a long time ago. I had a e21 323i that had K-Jetronic. I fitted the engine to an "newer" e30 320i with L-Jetronic (fuel control only). I was amazed how well it ran. To all intents a fast 320i. From looking into the engine bay it looked standard. The extra 300cc made no difference as it provided sufficient fuel.
But thinking about it the first cars I had ran with carburetors and distributors. Ignition control was by springs and fuel control by "holes". So a crude system.

Your car is an M535i with a much better looking engine. The compression ratio of the M30 is similar to the US s38b35. The displacement is similar. The main difference is the 24 valve head will flow more air at higher rpm than the M30. The M535i motronic probably provides enough fuel but you could check with an air/fuel gauge.
The main reason for the different DME was that they could be tuned for each application. I have an e28 M5 full fat version, the DME is unique to the M5 and the M635csi.
Having the correct DME should in theory unlock the full potential of the engine.
Another option is to fit the DME and loom from a late e24 635csi or an early e34. These had Motronic 1.3 which was an improvement over the older motronic of the M5 euro and the motronic in your car.
Does your car have the two sensors on the gearbox?
robertodonnell
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Re: Motronic 079 and 059 Differences

Post by robertodonnell »

Hi guys,
Bit of an old thread of mine that's seen a revival!

TBH the engine runs fine on the wrong ecu, but at any rate I'm swapping it all out for a custom tuneable ECU and doing some stuff to the engine to unlock all the power these donks have. This will also mean removal of the antiquated flapper air flow meter, which in itself should improve engine air flow at higher RPM.

I decided the car is unoriginal enough to warrant this, as it's never going to be anything other than a mish mash of different cars, albeit a bloody good one!

Cheers,

Rob
Syndrome
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Re: Motronic 079 and 059 Differences

Post by Syndrome »

Yeah, I tend to look for old, relevant threads and revive them whenever possible. I think it can be better to build on old knowledge and experience than to start new threads and get part way there. I have a question for the DME gurus. Is it possible that the only difference between the 059 and 079 is the chip? Isn’t that where the specific programming resides? In other words, would it be possible to have a 059 DME with a 079 chip in it and have the very same results?
robertodonnell
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Re: Motronic 079 and 059 Differences

Post by robertodonnell »

Exactly what I was theorising. Essentially it's the same engine with more revs, so the ecu just needs to be able to cope with the increase in fuel demand and deliver it. The AFM would need to have a greater range too I suppose.

Before I wrote off this, I spoke to some BMW specialist tuners about having a chip flashed to do the job. Nobody in Aus had the data needed, so I would be spending money to have a dyno run (or runs) done to make an appropriate tune. After that I just decided a modern ECU would be a better way to spend my tuning money...
Syndrome
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Re: Motronic 079 and 059 Differences

Post by Syndrome »

Is there a turnkey modern ECU out there? I’d like to have contact details and other info, please!
///M
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Re: Motronic 079 and 059 Differences

Post by ///M »

One of the things with the AFM is that over 4500 rpm it tends to be fully open and fuel and ignition are the main factors. I have never been a fan of the tunning side of things. My way of tunning is to fit a bigger engine. To improve the power of an E30 I fitted the E36 M3 evo engine. So out of the box 320bhp that will run around town all day or drive 500 miles without problems.
Paying for dyno time is expensive. BMW spend a lot of money on development, no one without a limitless budget will match it for all round drivability.
With regard to the DME it is something that I have considered doing. If I cloned the chip in a e34 M5 DME that i have and fitted into the DME of a standard e34 535i (both are motronic 1.3)
As I mentioned and as robertodonnell found in his car, the car may run but you need a dyno with before and after to get an objective result to see if there are any gains.
In my time I have seen people spend large sums of money for little gain. My favorite was at a track day where there was a 1000bhp BMW e30 (really?)
I do not think it managed many laps and never went past me. Reminds me of the old joke "I have a 12" member but I don't use it much as a rule"
Syndrome
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Re: Motronic 079 and 059 Differences

Post by Syndrome »

Interesting. I happen to have an e34 M5 DME in the garage. Two questions. First, would its chip fit directly into an 079 E28 M5 DME? Second question, would that do anything good? Thanks.
///M
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Re: Motronic 079 and 059 Differences

Post by ///M »

The e28 has the earlier motronic so is not compatible with the e34. The e28 should have the two sensors on the gearbox the e34 has the one on the front crankshaft damper.
I have an e34 535i engine and loom so to do a modification to an e28 M5 engine the components are theoretically as follows
e34 M5 engine DME and loom fitted to e28 M5,crankshaft damper with toothed ring. Problem is the MAF on the e34 is unique so you would have to use it. This would be the best combination most similar to the e34. Not a e34 M5 but a similar engine with different management. You would want a good improvement if you were to pay for the parts. The MAF is very difficult to find and a crazy price. An M3 engine would produce more power for probably similar outlay.
For a Euro car the e28 M5 has 286bhp and the e34 M5 3.6 has 315bhp. You would not match the e34

Other option is the e34 535i loom and DME fitted to the e28 M5 with e34 AFM and a chip from the e34 M5 DME. The e34 M5 DME would connect up but from memory there are some mismatches so each pin must be identified on the loom and the DME.
I do not believe this would work.
The reason is the MAF on the e34 M5, the e34 535i loom has an AFM. So while you can fit the chip the wiring is mismatched. That is a no go.

The way to view it is that the engine does not care about the management system (as long as no large change in displacement/compression ratio) as much as the management system does care what electrical components it is connected to.
You could possibly get things to work together but the easiest and cheapest solution is the correct DME for the car. That is the reason that I follow the American idea "No substitute for cubes" (may not be technically correct)
Syndrome
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Re: Motronic 079 and 059 Differences

Post by Syndrome »

Interesting stuff! Would there be any benefit in putting my E34 M5 MAF and air cleaner setup on my E28 M5?
///M
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Re: Motronic 079 and 059 Differences

Post by ///M »

What other parts are you hiding? For BMW I like to think "Lego". If you have the e34 M5 MAF and DME then you have the main parts of a conversion to the motronic 1.3 on the e28 M5 but you would need the e34 M5 engine loom or adapt a loom from another motronic 1.3. It would not be just plug and play.
You would be missing the air intake system of the e34 M5 which was part of the improvement for the e34.
When I was playing with BMW "lego" parts were more readily available and sometimes I picked up parts or cars for free. The e34 M5 parts you have are worth money to someone. Fitting them to an e28 could be done but gaining very little improvement in performance.
Making changes to something like an M5 is probably going to devalue it as people want originality.
robertodonnell
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Re: Motronic 079 and 059 Differences

Post by robertodonnell »

The E34 M5 DME would need a proper dyno on the E28 M5. Smaller capacity and less cam would mean less fuel.

To be honest, I would not even bother going that way. If you were to use a more modern aftermarket ECU (and they are getting cheaper used), you would benefit from things the M1.3 doesn't have. Such as a variable TPS input (M1.3) is idle, off idle, and WOT), and a full wideband O2 sensor input.

The above is why I decided to toss the OEM and go aftermarket.

These alone would improve driveability, and probably fuel consumption. Change your exhaust cam to the S14 Evo cam gear, and get maybe another 50 HP!
Syndrome
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Re: Motronic 079 and 059 Differences

Post by Syndrome »

OK, now you’ve got me. My E28 M5 is a really nice, fully stock example. It sat for many years after it overheated under previous ownership. It’s a California car, which even had the cool chrome plated stock E28 M5 wheels, so there is no rust anywhere on the chassis. All panels are original with their matching VIN. Even the paint is all original and very presentable. I’ve dumped so many hours and dollars in so far that I insist on perfection at this point. For me, it’s been a real labor of love.

I am on the hunt for another stock 079 DME (at a price that I can actually afford at this point in the game, without having to forego lunch and dinner for a month, ugh). Alternatively, I’ve heard there are modern DMEs that are cheaper and, arguably, better than the stock DME. But I have no information about this unicorn. Does anyone know exactly what DME I’d have to source, in detail? As long as it’s plug and play and I keep the original, it wouldn’t devalue the car. Can someone please help me with either a stock or modern DME for my lovely old car?

Almost everything on my car that was affected by its overheating has been rebuilt using parts I buy at the BMW dealership near me. Whenever things are no longer being produced by BMW, I’ll get them fromTurner, ECS, FCP, etc. Now, I’m trying to shake out some running issues. I’ve always had and worked on Porsche 911s, and these are my first forays into Bimmer world. Now I know why Rommel liked oil cooled motors in the desert. Overheating is a really sucky problem for water cooled motors!

Now, the car is back up and running, but not yet to a level I expect. Basically, it’s not perfectly easy to start up, it runs a little roughly (until it doesn’t, i.e. it sporadically runs better with a bias toward rough running), throttle response is a bit slow, and it has some small backfiring in the exhaust). Everything in the fuel delivery system is new, new OEM ignition is all new, all sensors are new and OEM (unless I’ve missed something I’m not aware of), all new cooling system, all new rubber hoses, bellows, etc. No known vacuum leaks. There are no dummy lights lit up, other than the brake light warning caused by a crumbled brake switch under the pedal. I have a new switch arriving today. The engine runs at a nice temperature too, which is great.

So here I am. Who can help me diagnose this final problem so I can finally put this thing to bed? I hope I’m not the first and only guy who is or has gone through this process.
Last edited by Syndrome on Jul 27, 2022 6:43 AM, edited 1 time in total.
robertodonnell
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Re: Motronic 079 and 059 Differences

Post by robertodonnell »

So you have the 079 ECU already?

If you have the inclination, I would knowledge up on the beast that is the Bosch Motronic:

https://mercedessource.com/store/bosch- ... ent-manual

If you don't have one and you need to source one, I would go full on OEM with your car. My car is different, it engine swapped and doesn't have any cache like yours, so I can go hard and not devalue my car. Yours, on the other hand, it's worth more stock.
Syndrome
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Re: Motronic 079 and 059 Differences

Post by Syndrome »

Yup. I do have the original DME in the car. I’m 50% sure the DME is causing my problem. Yeah, that’s a really low level of confidence. I just don’t know what else to look at. Ideas? Tell me about your DME.
robertodonnell
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Re: Motronic 079 and 059 Differences

Post by robertodonnell »

I think my DME is a 535i one, with the loom hacked to fit the S38. No idle control, I have traced it back to the ECU as faulty. Engine runs well enough, but seems to lack what I think it should have.

I am in Australia, and over here there are places that can set your ECU up on a bench, and simulate the car running to diagnose faults and repairs. I would perhaps look at that, are confident there are no sensor faults and the engine isn't the issue.
Syndrome
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Re: Motronic 079 and 059 Differences

Post by Syndrome »

Thank you!
///M
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Re: Motronic 079 and 059 Differences

Post by ///M »

So all of this is because your car is not running correctly? I would forget all of the above and get the standard system working. A lot of threads on the forum are about people swapping lots of items and not fixing the problem and blaming the DME then replacing the DME and it is still not fixed. When I first worked on cars this would have been seen as someone who does not know what they are doing. Of course they were simpler then.
But as things progressed even Main Dealers were guilty of the practice when stuck. They would put the part back on the shelf for you to buy and tell you there is no return if you fit it.
What is the problem with your car that you are so keen on a change of management?
robertodonnell
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Re: Motronic 079 and 059 Differences

Post by robertodonnell »

I am not sure who you are directing that question to?

If it's me, I have decided am not going to go down the OEM path. I have plenty of standard cars to enjoy, should I wish to! I posted this thread just after I acquired the car and now I know a lot more about the 079 DME, It's not going to do what I want it to do when I upgrade the engine's internals.
///M
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Joined: Apr 17, 2009 11:21 PM

Re: Motronic 079 and 059 Differences

Post by ///M »

Hi robertodonnell
The response was for Syndrome. I know that it is easy for people on forums to get the wrong impression. I am not telling you what to do with your car. So the best of luck to you and Syndrome with your cars.
robertodonnell
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Re: Motronic 079 and 059 Differences

Post by robertodonnell »

Agree completely mate, but yes his car is certainly more worthy of chasing the OEM route.
///M
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Joined: Apr 17, 2009 11:21 PM

Re: Motronic 079 and 059 Differences

Post by ///M »

Hi robertodonnell
I think that we share the same opinion on Syndrome's car a car to be kept standard.
I would have more interest in the road you go down with your car. I did my first engine swap in the early eighties and my interest was only in modifying
cars. People spent time and money on performance parts. I fitted bigger engines. Back in the 90's new magazine at the time did some dyno tests before and after, one that I remember was a K&N intake and filter fitted to an e30 320i. The car lost power. Other tests on performance parts were similar. Now of course what happened was that that practice stopped. Advertisements in magazines are the major income so don't do anything to jeopardize the income. From then on more of "you could expect to gain X number bhp" in other words what the manufacturer said it gained. I always wanted the biggest bang for the buck.

I would have the same idea as you with regards to modifying your car except I always did it to the cheapest car. A lot of the likes of the 518 were often better as they could be one owner low mileage but little value. Point being the parts were worth more than the car. Sell the parts and you lose almost nothing. The M535i used to be cheap car as people moved into secondhand e34's but now big money.
If you are going to modify your car I hope that you put the build on here. I enjoy reading other peoples builds that go in a non standard direction. They are much less frequent now as the value of the cars has risen.
Particularly interested in the aftermarket engine management and what is involved for the investment of time and money. Other peoples experiences have put me of. Various examples over the years of people spending huge sums of money. There is a guy in Australia with a 6 series putting in the e34 M5 3.8. As one person said he was paying people to learn on his car. I could have bought the e39 M5 engine and gearbox almost 400bhp out of the box for a fraction of what it was costing him was all I kept thinking. There are parts from the e34 that could be used in your car if they are still cheap in Australia.
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