M635CSI ECU (055) help needed!

[masterdog]

Hmm, well, good luck with it!

I meant to mention that the internet leads me to believe that all big 6 (of the era) water pumps are currently the same replacement part.

Offer still stands if you want me to use my car as the guinea pig with your ECU!

Cheers,

Ray

I thought the same thing about the pumps before, but it turned out m88/s38 engines use more powerful one (p/n 11511312539).
I think it produces 1.4 bar instead of 1 bar standard, but I may be wrong.

I do know that after I installed the correct one I could actually FEEL the difference squeezing the hose.
What's misleading is that they DO look almost identical and differ only in impellers...

Thank you again for going through all this trouble for me!
And I appreciate the offer, but as of now I firmly believe I have the wrong ECU so there's not much point in subjecting your car to the misery of running with it...

[rlkrlk]

BfC doesn't like your attachment

But I have an inkling anyway.

So, what is your plan now?

Just for grins I drove around the block with the Lambda box unplugged. No difference noted, tho I suppose the Motronic may have been moreso in open-loop.

Cheers,

Ray

[masterdog]

Ok, I'll try again )
911.jpg

This post also lists some component part numbers, that match your ECU, but not mine...
https://members.rennlist.com/messinw...TimPolzin.html

I'm on the mission now to figure out what the hell do I have for the ECU )

What I've just learned is that Bosch part number does not positively identify ECU, there could still be differences from unit to unit.
I also understand, that although components may be located in slightly different places from board to board, they still bear the same number and apparently same function.

[rlkrlk]

That sort of makes sense. Like 2002 (the car) turn signal relays being different internally and carrying the same p/n. As long as it functions for the purpose, it works.

[masterdog]

Ok, after spending most of the day in front of my laptop I've learned 2 things:
1. If I look at another photo of ECU I will probably throw up
2. I did not find the picture of the ECU that I have, I did find the one that has same PCBs, but not the components.
Here's the photo:
078-.jpg

What I'll try to do is to copy your ECU as much as I can.

It turns out that there's not that many differences between the two - I've circled the chips that actually differ, so I'll replace those and see what happens.

055b2.jpg

I've also learned that my ECU is originally not-catalyzed and probably is made for 4k chip, but was converted to 8k by jumping 2 pins later.

Probably it also had 24 pin socket and later was upgraded to 28, but I'm not sure.

[rlkrlk]

To revisit the water pump discussion here, I did do some research before going with the Graf pump, which is spec'd as fitting the M30 as well as M88, S38. There are a number of messageboard threads where some notable contributors had said using M30 pumps caused no issues. Blunttech as well as Turner sell pumps listed as fitting all those motors, rather than M88/S38 specific pumps.

The Graf I bought from Blunttech is described online as a completely new, not rebuilt pump (not written up as such on the Blunttech site tho).

I'm wondering if the impeller design was changed to universally accommodate.

I did compare my original and the replacement pump and while I didn't measure (or count!) the impeller vanes, I saw no difference in design.

The temp gauge rides where it always has in the car; just about in the center.

All FWIW!

Cheers,

Ray

[masterdog]

Well, if it is spec'd to work on both, I guess it should work. Especially if your temp is where it needs to be.
Maybe all modern pumps are made more universal, it kinda makes sense, but the fact that m88s have larger coolant capacity so there's more fluid to move around, which would require more capable pump back in a day, makes sense also.

What I had on my engine was an older pump made by BMW, which led me to believe that it was the original unit installed at the factory.
I might still have it laying somewhere, I'll try to dig it up.

But when I ran the part number off it back then, m6 was not listed, so it was a no-brainer - I just replaced it. And there was a difference.

Actually what bothers me about my cooling system a bit is the fact that I don't think I've EVER heard my aux fan coming on (except for when the AC is on).
Both temp switches are new, in fact they are both 82 degrees.
All circuitry is fine, shorting the wires does trigger the fan, I've removed the radiator, cleaned it and had it checked and it seems to be ok.

[rlkrlk]

Well...

https://smile.amazon.com/Etekcity-La...rmometer&psc=1

- - - Updated - - -

And now that you have me thinking about it, I'm not sure I've heard mine run!

[masterdog]

I think the problem is also in the location - those switches are in the area where the water has cooled down quite a bit (unlike the temp sensor that is placed in the hottest part)

Back to my favorite problem - I've found another part of PCB where component was removed (the very top square, one of the resistors):

02.jpg

I'm still searching the web using different BMW and Porsche part numbers and I do occasionally find new pictures of PSBs that give me more and more information.
Also a lot of solder joints on my boards were reflown, so sometimes it is hard to tell whether the component was replaced or was it just reflown.
As of now I do believe that I have an ECU from Porsche (I know it's very unlikely, but my top PCB looks exactly like 911 Porsche from late 80s), and most likely European...

So my plan for now is to make my boards look exactly like yours by replacing all non-matching components. I know it's not too much of a plan, but that's the only one I can think of right now ))

[rlkrlk]

Keep us posted!

Cheers,

Ray

[sofiabghome]

Hi Gents,

Let say hypothetically M635CSi owner does not want to
add Stand Alone, then..

In Socal M635CSi is not so friendly
in therm of emissions as we all know
and some other areas as well and passing
smog is not possible.

Moons ago I had converted S38-B35 complete
harness transferred it to M635CSI M88/3 and
adding the proper and really operating 02 Sensor
not like that Jansen rubbish box which never ever
f. work properly.......I think that was just to dust
off the EPA pass.

Any M88 will chew up any cats installed in no
time.

Installing the S38-B35 harness including the 079
is really Win, Win, over the original M88/3.

The car becomes a lot more drivable and friendly
and pleasant to enjoy.

The fueling mixture and the potential to tune is
more friendly and precise for variety of
weather temperatures over the standard.

One can add 02+Cats and tune it more properly
and still make power out of the M88/3 engine easy
because has the 264s already and the M88 headers.

From 88' M6 untouched engine, just M88/3 Headers,
3.6 Cams (my timing), exhaust, Miller Maf. I am able to
pull ~267RWHP, it does eat any stock M635CSi in existence.

But then, if convert the M635CSI will make
more power because the gains from the 10.5CR
are obvious over 9.8CR.

MPG ? it does improve dramatically and so carbon
build up is reduced by massive amount.

It does extend the piston rings live as well, burning
in most of the time on the rich side is washing
little at the time the rings and then, every M635
when you rev it to 6k rpm and then let the
throttle off a big cloud of smoke come from the
muffler unless fresh rebuild.

My customer till today could't be happier whit my
conversion on his M88/3.

Passes smog like S38-B35 in the skin of M88/3 with
the proper set up because easy on the Eprom.

Personally never been a fan when one drives M635CSi
with open windows and then, red light approach to
stop and very little wind from the back make the
cabin to stink like very very bad.....even driving
on the freeway I can still smell the de-cated set up.

Full blown race car then fine but for what most
M635CSI owner are using it for then no brainer.

For the purist ? Still remain original matching M88/3
but much more friendly and properly running engine.

Just a thought, makes one to think hard..

Regards
Anri

[masterdog]

Thank you for the suggestion Anri!

Thoughts of standalone and other ways of dealing with the issue have passed through my mind many times, but right now I really want to finish the car sooner and be done with it, rather than turn it in another project.
Especially if it involves dealing with the exhaust again. I mean I do weld, the current piping on my car was made by yours truly, but I utterly hate working on exhaust.
Plus between x-pipe, 2 flex joints, 2 huge resonators and a muffler, there is NO extra space down there now, so if I wanted to add cats I would have to do quite a bit of work....
I mean if I stumble into cheap 079 ECU I will definitely buy it, I don't see much problem in modifying my harness a bit, adding that pressure sensor and purge valve what have you, just hate returning to this exhaust again...

[sofiabghome]

Hey Masterdog,

Always, sir.

Well, don't be lazy, hehehe
specially if you weld. Easy to
convert, then.

Think, what's another week in
wee hours of fun Wine work ?

Then Masterdog will cruise and
not to worry for smog and
rich burn smell and can make
a family trip whiteout poisoning
the people inside the cabin...

Mpg will be more easy on
the pocket, fuck, even with 3.73
longer differential and nearly
350pounds lighter than S38/M6
Half a tank goes in just to go the
caffe shop in spirited driving.....

Regards,
Anri

[rlkrlk]

I remember reading somewhere that the 055 ECU does have provision to run closed loop. Maybe a search of the pinouts would shed some light on that...

Cheers.

Ray

[sofiabghome]

Hi Ray,

If price was skyscraper
for 079 then may worth
to look over 055 and search
for to covert 02 and then
If can happen its not
sure thing, tell you that..

Easy to spent tons of time
trial and error then not
worth it, knowing a used
079 runs for $350-450 range.

Then sell 055 for a purist ?
for $ then its really
win win option for
basically, just exchange ?

Regards,
Anri

[masterdog]

Ray, AFIAK this area in Motronic ECUs is responsible for dealing with O2 sensor and is empty in 055:

Capture1408367321.jpg

Anri, selling my 055 is not an option at the moment since I do not know if what I have is actually 055 ECU nor do I know what exactly is it...

[masterdog]

Here's my attempt to get some help from Porsche guys.
It turned out to be very entertaining! ))

https://rennlist.com/forums/911-foru...fy-an-ecu.html