RomRaider

Hi
Car e36 m52b25 euro ms41.0 with m50 intake (IAT sensor from m52)

When I look at the knock adaptations in the romraider logger they are very large (-3 to -6) on the stock map on 95 RON and LPG

Ecu has no errors
sometimes it seems to me that the car is weaker, especially when it's hot outside. In winter the adaptations were close to 0 (sometimes -0.38 max -0.75)

what can cause this ignition retard?
Carbon deposits? Or old knock sensors?

somethings to check/consider
- check compression on all cylinders, a worn engine can show high knock
- The m50 manifold lowers load in the low rpm range, the ecu might advance the ignition too much
- Your knock sensors have worn or are installed incorrectly and give wrong readings

I will check compression, but 1 or 2 years ago it was about 12,5 - 13 bar

It's not like these knock adaptations will always be some because the map is for RON 91-98 and the ECU adjusts itself to the actual fuel?
Do you have 0 values (or near 0) ​​on the stock map?

I forgot to write earlier that I drive on the 1430630 s962 map (special engine characteristics)

I checked the compression - 12bar on each cylinder
I changed the knock sensors to new VDO, tightened to specification at 20Nm
New intake seals
Replaced coils (new Bremi) and spark plugs (NGK iridium BKR6EIX)
New oil separator oem bmw
Replaced with a different TPS and MAF
No air leaks, checked with smoke machine

I have no idea what could be causing it
Any other ideas?

As a test you can use a bit of higher octane fuel when your tank is near empty and see if its actually recording engine knock.
With better fuel the amount of knock you see should decrease or go away completely.

Why are you not on a "normal" SW-version? Do you actually have a "special"-engine?
If you have a standard Alu-Block M52 then its best to use for example SW 861.


If that doesnt help maybe look at:
-any vibrations from exhaust?
-Something touching the chassis/drivetrain?
-Motor+Trans mounts ok?
-bolts coming loose?

I use 1430630 because it accelerates better from low revs, 1430630 is not for the special motor option, which has a cast iron block, for it there is a different software number according to ETK. if i remember correctly it is 1430631 (s961 special motor)

LPG has a higher octane number than 95 RON petrol. I use LPG more often because it's much cheaper than petrol. But when i drive on petrol these knock table values ​​are same. The worst values are at 4th cylinder

I would flash 861 with winkfp and check it again. Maybe it's the fault of the 630 software

Answering your questions
-any vibrations from exhaust? - No vibrations
-Something touching the chassis/drivetrain? - Nothing touching
-Motor+Trans mounts ok? - Replaced 3 months ago when i changed oil pan and clutch
-bolts coming loose? - front axle support tightened when replacing the oil pan, any others screws too

Is it normal that the engine temperature on the thermostat 88°C degrees reaches 103°C at idle? New water pump with metal impeller (hepu) and new radiator (behr).
Clutch fan works ok, and aux fan too (I have replaced the thermoswitch in the cooler versions from R4 for lower switching temperatures (80/88°C, fan stage1/stage2)

My aluminium M52 reached 100C at idle as well. I have big radiator on my E36, only electrical fan in front of the radiator, no AC. IIRC the thermo switch is 80/88 BUT it is measured after the radiator, when coolant is about to enter the engine again. Idle temp climbed down to 86-90 when I replaced the thermostat with 75C version - the fan still comes on, but temperature is significantly lower. I had troubles with the temperature rising over desired values in the end of the race while driving on a slow track and cooler thermostat helped (I will also get dirt in the radiator during the race, which worsens the cooling capacity a lot). I think the temperature rising during long idling is actually okay.

Good that you checked the basics.
If it doesnt go away with higher octane fuel it seems like its not real knock its detecting.


why would that be?
Even if 630 had a performance advantage (never heard about that) in the tune you could just tune 861 for the same afr, timing and tip in etc...
I believe it would be worth to try 861 SW to see if logged knock changes.

Did you check if there's a timing chain slack?

I changed the software to 861, the values ​​decreased a little, but they are still high in the low rpm and load columns. There must be something wrong with the engine or equipment.

I set the timing a few years ago when I was regenerating the Vanos. In inpa it shows the camshaft position value 21-22°
The main timing chain tensioner was also replaced with the S52 version, which is stronger

Good that you checked. Have you decreased the ignition advance just in those areas to see if that helps?

It points towards being fake knock from some sort of vibration. Maybe try logging knock on a perfectly smooth road to rule out some externally introduced shake...

When looking at this i mostly go of the saved knock adaptions. When you pull the adaptions after a drive with car still running you get the detailed version for each cylinder (this can point to an actual issue if always the same).
When you shut the car off for a couple of seconds and then read the knock adaptions you get the "stored" adaptions which are made up from the worst of the individual cylinders and are applied at the next startup.
My philosophy was always that if the stored adaptions are very small its just single events that happened by chance and not a drastic and constant problem with the engine or tune.

At which ones are you looking mostly?

Have you found a solution to the problem? I have the same one.

Hello. There was such a problem. The problem has gone after replacing the bearing of the generator and the belt tensioner roller. The noise of these bearings falls into the window of determining the detonation of the ECU and makes the ignition angle ... The tech can also make noise.

If someone is reading this post, My car also had similar knock adaptations on low rpm and hesitations. The vanos wasnt working at all. When i made my vanos work knock adaptation disapeared.