3.6 conversion idle problem/ECU help

[mysocal911]

Originally Posted by ischmitz

Not sure what you refer to as "strange". The white stuff is glue to support the resistor and normal.

Actually, the part is a diode.

[ssfrancis]

Ingo- Thanks! I've never seen anything like that on a board. I was worried it was an addition.... looks kind of shotty

Kaefer- Thanks as well. I could not decipher writing.... know anything about their 3.6 chips?
I have an email into them to get some info.

[PcarPhil]

Originally Posted by ssfrancis

Kaefer- Thanks as well. I could not decipher writing.... know anything about their 3.6 chips?
I have an email into them to get some info.

No I don't know about their chips. My knowledge is with Steve Wong chips, Cyntex chips, and OEM chips.

IIRC I believe Ingo also offers some nice DME chips!

[ssfrancis]

Oh I've been reading about Ingo's chips... very cool

I just want to be sure that this is my problem before I throw more money at it. I'm trying to find another ECU to swap in to be sure.

[ssfrancis]

Just curious, but why does this DME not have the gob of silicon?

3.6 conversion idle behaviour with Steve Wong chip

[Bill Verburg]

Here's one of my 55pin 993 DME's, they both look the ssame to me, except for the chips which I installed

I think that this is the '97 RoW

[ischmitz]

In the OP's DME an axial resistor is installed in place of C232. Not sure about why but my assumption is that it helps bleeding off charge in some filter capacitors when the DME is shutting down. Bill's DME doesn't have this resistor. Could be a different revision.

Ingo

[mysocal911]

Originally Posted by ssfrancis

Just curious, but why does this DME not have the gob of silicon?

3.6 conversion idle behaviour with Steve Wong chip

That one and Bill's are ROWs and not USA.

[Bill Verburg]

Originally Posted by mysocal911

That one and Bill's are ROWs and not USA.

US '95 and RoW '94-98 normally aspirated are all the same 55 pin Motronic 2.10 DMEs

the codes for both are in every unit and are accessed by varying the connections between pin2 and pin 54
2-54 open is RoW
2-54 connected is US
2-54 w/ 1kΩ is for the leaded gas no O sensor versions
2-54 w/ 14kΩ is for RS

all have a user removable chip

I have used the one in the picture to control both a US 95 non vram and a RoW '97 vram

I did have to have it rebuilt last year as some of the plastic components and solders were failing.

[scarceller]

I suggest putting an o-scope on the 2 ICV signal lines. You need to know what the duty cycle is telling the ICV to do. The signals are 2 square waves that are 180 degrees (opposite) of each other. So if one is 25% off and 75% on the other is 75% off and 25% on. I've seen a few 84-89 DMEs with a drive transistor shorted so that one of the lines is shorted to ground.

Would be nice to know what the signals on the 2 lines look like.

Also test the ICV, search for "bench testing idle control valve" in this forum.

[mattC2993]

Can you try another chip to see what happens? I've got one out of my '95 Carrera you can have for the price of shipping. I think it is aftermarket (came with the car and got replaced with a Steve Wong chip).

[mysocal911]

Originally Posted by Bill Verburg

US '95 and RoW '94-98 normally aspirated are all the same 55 pin Motronic 2.10 DMEs

the codes for both are in every unit and are accessed by varying the connections between pin2 and pin 54
2-54 open is RoW
2-54 connected is US
2-54 w/ 1kΩ is for the leaded gas no O sensor versions
2-54 w/ 14kΩ is for RS

all have a user removable chip

I have used the one in the picture to control both a US 95 non vram and a RoW '97 vram

I did have to have it rebuilt last year as some of the plastic components and solders were failing.

Obviously both units are 55 pins and both have removable chips, but as one can see
there are component differences on the two circuit boards. There was a reason for
labeling the one ROW and not other, and that would not have been the case if
changes were only made by external jumpers.

[mysocal911]

Originally Posted by scarceller

I suggest putting an o-scope on the 2 ICV signal lines. You need to know what the duty cycle is telling the ICV to do. The signals are 2 square waves that are 180 degrees (opposite) of each other. So if one is 25% off and 75% on the other is 75% off and 25% on. I've seen a few 84-89 DMEs with a drive transistor shorted so that one of the lines is shorted to ground.

Would be nice to know what the signals on the 2 lines look like.

Also test the ICV, search for "bench testing idle control valve" in this forum.

That is the best approach to take. It's very unlikely that the chip is the problem.

[scarceller]

If you need a 1995 993 chip I have 2 bin files I can burn

the 164 - M04MOTRONIC9936181230202612031631267358164
or
the 948 - M04MOTRONIC9936181240402612036751267358948

I assume the 948 bin is the latest but I'm not sure.
If you can't locate a factory chip I can burn one for you, PM me if you need help.

One more idea: do you have access to test your DME in another car? That would be helpful.

[ssfrancis]

Thanks for all the replies guys.

Last night I went throughout the entire harness looking for problems. Cant find a thing.

I think I tracked down an o-scope so I'll try it this weekend and report back.

Thanks for the offers on the chips I'll PM. It would be good to have for trouble shooting.

[ssfrancis]

Just got this back from FVD regarding their chip:

"Chip is today same like 99.
It is non Vario EU DME without immobilizer CU.
Octane rating should be 98 (EU DME). Could work also with less but also with less power.
There is no any changes on idle"

So obviously the octane is way off.... Since there is not change in the idle settings could the light weight flywheel be causing the high idle?
3,000 rpms seems a bit high though.


Guess its time for a new chip!

[Bill Verburg]

Originally Posted by mysocal911

Obviously both units are 55 pins and both have removable chips, but as one can see
there are component differences on the two circuit boards. There was a reason for
labeling the one ROW and not other, and that would not have been the case if
changes were only made by external jumpers.

I guess you just don't understand how Porsche does things. I am not making anything up. If you read the actual tech manuals they explain it all. They wanted one part in the bins that could be used in multiple chassis. Same thing for the 55 pin harness, there is only 1 and it has all the plugs for vram and non vram, US and non-US

There may have been evolutionary changes from '94 to '98 but they all are functionally interchangeable through the 2 pins and chip

Of course the turbos and US from '96-98 are different, they are 88 pin, in fact '96 was different from '97/98 wrt to hardware but was still interchangeable.

[scarceller]

Put a stock chip in the DME, see if it solves the problem.
Even with light flywheel it could stall when returning to idle but once at idle should idle fine.

Originally Posted by ssfrancis

Just got this back from FVD regarding their chip:

"Chip is today same like 99.
It is non Vario EU DME without immobilizer CU.
Octane rating should be 98 (EU DME). Could work also with less but also with less power.
There is no any changes on idle"

So obviously the octane is way off.... Since there is not change in the idle settings could the light weight flywheel be causing the high idle?
3,000 rpms seems a bit high though.


Guess its time for a new chip!

[uwanna]

Originally Posted by ssfrancis

Just got this back from FVD regarding their chip:

"Chip is today same like 99.
It is non Vario EU DME without immobilizer CU.
Octane rating should be 98 (EU DME). Could work also with less but also with less power.
There is no any changes on idle"

So obviously the octane is way off.... Since there is not change in the idle settings could the light weight flywheel be causing the high idle?
3,000 rpms seems a bit high though.


Guess its time for a new chip!

RE octane ratings: Euro ratings are computed differently than US ratings.
98Euro= approx 93.5 US
check this:Octane rating conversions - PencilGeek's BMW Blog

[Alex973]

my first problem was hunting, Bill V. helped me with the diagram of V-ram
second was my ISV I cleaned it
3rd problem was 02 censors was not plugged in, I bought harness plugged
it in vola no mo problems, good luck