jumph4x

The code keeps coming back.

On our C36's the knock sensors are in pairs, connected by 2 leads from the engine harness. Both are identical. I believe the OEM manufacturer is Siemens.

So I got the code above a while back. Bought one of these, replaced one of the two, reset the code.

A week later the code came back. So I swapped the sensor with the second one (thinking i guessed and replaced the wrong one).

Now the code is back again. I know these sensors are VERY hard to test, and I know the harness has already been replaced with a good one.

I only put Shell\Mobil Octane 93 in this car.

Any ideas, anyone?

hcetzneb

How's the engine harness look??? Check the ends they could be shorting together very common on the 104 eng.

jumph4x

Just took off both sensors and flipped their positions again. Ends look perfect. Brand new. Shiny shiny copper.

jumph4x

Does anyone know which is sensor 1 and which is sensor 2?

appatula

Dennis, hope this helps!

jumph4x

Very helpful! My Bentley book shows the same images, but doesnt actually list out which sensor is which.

This goes in line with my guess, front of the head is knock sensor one.

Ordered another new one, will put in this weekend.

appatula

Good luck! Keep us posted

jumph4x

Son of a *****. I got some sort of an uber cursed ****ed up C36.

2 brand new Siemens OEM sensors and the ***** still aint happy. Harness is like perfect? Is it my ECU?

I'm losing my patience on this...

RANDY_P

Didn't you just do a mail order tune on this car?

Probably too much advance. It could be in fact detonating and you just don't hear it. Before you go any further you might want to swap it back to a stock tune and see if the codes go away. If that's the case there's no parts you're gonna buy that will alleviate the problem. The car could be working just fine.

Frankly, in a lot of cases all they do is just crank up the advance - removing the safety margin in case of bad fuel. That's why a lot of the mail tunes don't work so well..

rjp

appatula

man.....this is just crazy! I'm pretty sure ignition timing doesn't advance under 30C or so coolant temp (or something like that) an easy and CHEAP test to see if the timing is to advanced would be to trick the CTS into giving a false much cooler reading. A simple resistor can do this, PM Jay he has photos and has done this before (albiet for the exact opposite reason to advance timing but it should in theory work both ways).

jumph4x

No, we took the car back to its original settings.

I can monitor spark advance through OBD-2, that's not the cause.

appatula

Wtf

I feel like the checklist has been filled? What else could it possibly be? Could the actual ECU have been damaged?

How do they reflash the IC?
I'm almost positive that the chip where the .bin file is to remap is a SMD 68 pin PLCC (17 leads on each side). In this case I would assume that needs to be desoldered unless powerchip has a pin jig to touch the leads while flashing. Could be something to check out, maybe open up the box and take a peek in and look for anything out of the ordinary.

PS Dennis If you do know how they actually go about reflashing, whether it be desoldering the IC or flashing whilst it is still soldered in PM me the details, I'm becomming very interested in this topic.

I feel for you man!

jumph4x

Spoke with them a while back. What they actually do is desolder the entire memory chip, flash one of theirs and solder the new one on.

So they returned me to my actual map.

The reason car wasn't behaving right last time is because the chip they picked for the memory wasn't well received by the ECU. We will be trying this feat again very shortly. They're very nice people by the way.

appatula

Neat! Not to deviate off topic but if you get the chance, when they re-chip the ECU could you PM me a picture or partnumber of the chip?

Hope this solves the knock sensor issue anyhow.....

jayrasheed

i am more impressed Ben, question is, can we copy the map and reflash a similar micro controler / mem module?

appatula

Absolutley can . However we would need a modded ECU to start with. Then one could use ChipQuik to remove the remapped ECU. After that it would be a matter of finding a programmer and copying the bin files to a new (similar chip) and ChipQuiking it back in! I'm investigating to see if a PLCC68 pin socket could be retrofitted where the original chip is. If that is possible, not only would DIY remapping be as easy as popping the chip in and out to and fro the ecu to programmer but you could also retrofit an emulator for real-time tuning! (Not sure if ostrich 2.0 supports our chips though)

Other roadblocks still persist, such as figuring out where the hex "start" addresses for maps and other countless variables are. Then you will need to decypher the algorithm for the checksum and recalculate the checksum value. If you know ANYONE that could probe around for this info Jay please PM me, this would be insider information to the max though. I wish someone had a close friend at Powerchip or any of the other ECU mappers.... I kid....

jayrasheed

Ben, this is all well beyond me, but ill try not to disappoint. Ill probe a guy here to cough up how he reflashes our 95 ECUs. in the end if we do reach a point where we can remove a chip and just re flash it with new maps, i promise u from now serious improvements. my friend and I are not too shabby with tuning EVOs. Just get me a way to tune the car, PLZZZ

how much is a second hand C36 ECU ur part of the world?
Ill ask here if its not too expensive (u knowing me) im sure u know the next step

jumph4x

I think I know what was wrong. Fixed today. Took pictures of everything. I will keep driving the car and if everything is as I think it is, I will post here confirming it.

Great. Now I got even more perfectly working parts for this car. fml

appatula

The double edged sword!

jumph4x

https://mbworld.org/forums/c36-amg-c...low-input.html

jumph4x

Ahh I see. Totally neglected your reply, my bad. Thanks! This comment is spot on.