Monitoring CCT's with VCDS

[MDJ]

Someone chimed into a recent thread saying that CCT's can be monitored in blocks 90-93. I have a sneaking suspicion that the issue I've been having is just my chain guides, but I would like to be sure before opening up the top end.

I've never used these blocks before and was wondering what I should be looking for?

[budda]

All the info you need is here:

http://audisrs.com/archive/cam-timin...__t_21169.html

[julex]

block 093 will show you how advanced or late intake cam is in respect to crankshaft. Intake cam is driven by chain and shows effects of worn guides/wrong chain timing. In most cases, these are late (- value in block 093) and the more, the worse it is.

[MDJ]

Awesome! Thanks dudes!

I'll post back with my findings tomorrow.

[MDJ]

Okay, so as I make my way through that monster thread, I checked blocks 091, 092 and 093. From what I gather so far, the important info is phase position for bank 1 and 2. I'm showing +4 and +5 respectively. This info is telling me how many degrees each bank is out from the other, correct?

As for adjustment, I'm seeing a fluctuation from -1 to 0 degrees at idle on both banks. Is this telling me that my guides are starting to wear?

Please forgive my ignorance on the subject.

[MDJ]

Any input?

[AWDLAUNCH]

I will be looking into this also. In for input

[MDJ]

The thread posted is a good read if you're curious about this stuff. It jumps back and forth from timing deviation to other blocks of measurement, but all in all, a great bookmark.

[rnagy86]

Okay, so as I make my way through that monster thread, I checked blocks 091, 092 and 093. From what I gather so far, the important info is phase position for bank 1 and 2. I'm showing +4 and +5 respectively. This info is telling me how many degrees each bank is out from the other, correct?

As for adjustment, I'm seeing a fluctuation from -1 to 0 degrees at idle on both banks. Is this telling me that my guides are starting to wear?

Please forgive my ignorance on the subject.

Your readings are fine but you are on the margin though. I would break the cam sprockets and use a locking bar + crank pin to correct timing, because this way it is not perfect, but as I said, you will be fine as is.

[MDJ]

Your readings are fine but you are on the margin though. I would break the cam sprockets and use a locking bar + crank pin to correct timing, because this way it is not perfect, but as I said, you will be fine as is.

I'm thinking an incorrectly installed timing belt is the reason for the timing being off. I need to replace my cam seals, tensioner gaskets and guides anyway, so I'll be doing this at the same time. I've found a couple good DIYs for doing the above, but nothing related to timing each bank correctly. I'll probably document everything and make one.

[julex]

I'm thinking an incorrectly installed timing belt is the reason for the timing being off. I need to replace my cam seals, tensioner gaskets and guides anyway, so I'll be doing this at the same time. I've found a couple good DIYs for doing the above, but nothing related to timing each bank correctly. I'll probably document everything and make one.

+4 +5 is fine, leave of the way it is. Remember , this is not in degrees despite what vcds says. The difference on cam sprocket (inside the head) to cam bearing is probably about 0.5 mm off center, if that, barely noticeable by naked eye.

A bit ahead will actually make you good as it will make the timing belt stretching (with time and age) to actually slowly migrate it towards zero.

[MDJ]

That makes perfect sense. Thanks Julex!

[julex]

That makes perfect sense. Thanks Julex!

Sorry, edited my messed up phone reply so please read again. It should make sense now.

[airjawed]

I noticed that when my engine gets hotter the numbers get more positive. Is this from the expansion of the engine? It is in a V so the two heads are moving further apart as the block heats up...also they are both moving further from the crankshaft too right? The belt is not stretching so this overall engine expansion should make the phases all go more positive(relative to cold engine).

I do have a question though: How can you tell if your CCTs are actually adjusting? In block 094 in basic setting it will only tell you that the system is working(after increasing rpm above 2K). Output tests will let you know if the solenoid is working. But what about if the CCT is actually moving? Blocks 090-093 seem to reflect the timing but to my understanding give only an indication if the overall timing is correct. When I rev my engine in neutral and look at block 093 it doesn't change. Shouldn't it change as the tensioners get activated? Or does it only happen when in gear?

[julex]

I noticed that when my engine gets hotter the numbers get more positive. Is this from the expansion of the engine? It is in a V so the two heads are moving further apart as the block heats up...also they are both moving further from the crankshaft too right? The belt is not stretching so this overall engine expansion should make the phases all go more positive(relative to cold engine).

I do have a question though: How can you tell if your CCTs are actually adjusting? In block 094 in basic setting it will only tell you that the system is working(after increasing rpm above 2K). Output tests will let you know if the solenoid is working. But what about if the CCT is actually moving? Blocks 090-093 seem to reflect the timing but to my understanding give only an indication if the overall timing is correct. When I rev my engine in neutral and look at block 093 it doesn't change. Shouldn't it change as the tensioners get activated? Or does it only happen when in gear?

To give you an idea, here is a snapshot of the table that ecu uses to activate NWS (that's what it is called in bosch's nomenclature):



Y-axis is RPMs, x-axis is load (100% being max without activating turbos, basically atmospheric pressure open to engine).

So as you see, at 3k rpms, you have to really step on it while driving to to activate it. Below 2000rpms, you will never activate it since the engine can't generate enough flow (load) to step into nws activation area.

[phila_dot]

It is degrees KW.

Blocks 91 & 92 are wnwi(2)_w and block 93 is dwnwsp(2).

[julex]

that's way over heads of anyone on AZ

However, mechanically/logically a hair off the center mark on cam sprocket yields a lot off (4-5 correction factors) so I think ross tech is just converting wrong. Crank is just 2x amplified degree wise so it doesn't make sense when you are looking at the head exposed. 5deg would be much more than that 0.5 -1mm thing is off.

[ddillenger]

A buddy of mine emailed today after doing his TB service wondering about implausible signal codes. He checked block 93 and had +24 +21.

[MDJ]

^ whoa...did he put in a crank lock pin and pop the sprockets off to tension properly?

[airjawed]

I don't think the numbers in the blocks are degrees either. I recently had numbers of 7 and 9 I think and I popped the sprocket and adjusted it as if it were degrees. After starting engine I got timing codes immediately. I then adjusted back to where it was but ended up being off by a hair and then my numbers improved. Based on my experience it isn't degrees but perhaps some kind of factor.

[airjawed]

To give you an idea, here is a snapshot of the table that ecu uses to activate NWS (that's what it is called in bosch's nomenclature):



Y-axis is RPMs, x-axis is load (100% being max without activating turbos, basically atmospheric pressure open to engine).

So as you see, at 3k rpms, you have to really step on it while driving to to activate it. Below 2000rpms, you will never activate it since the engine can't generate enough flow (load) to step into nws activation area.

OK.... so it is normally load dependent. And looks to be either on or off. I guess I should log block 093 and do a WOT and see if the numbers go big if not something is stuck. I don't think mine is stuck since block 094 shows system OK.

From what I've read elsewhere they adjust the cam by 22 degrees when activated.

[phila_dot]

91 & 92 - actual shifting angle of the camshaft

93 - deviation of the adapted angle from engine spec setpoint angle of the camshaft (>0 too advanced, <0 too retarded)

[MDJ]

I don't think the numbers in the blocks are degrees either. I recently had numbers of 7 and 9 I think and I popped the sprocket and adjusted it as if it were degrees. After starting engine I got timing codes immediately. I then adjusted back to where it was but ended up being off by a hair and then my numbers improved. Based on my experience it isn't degrees but perhaps some kind of factor.

Interesting. In the thread linked in post #2, they clearly describe a read value of -6/+6 in phase positions as being 12* out. At the same time -10/0 would equate to 10* out.

[airjawed]

Interesting. In the thread linked in post #2, they clearly describe a read value of -6/+6 in phase positions as being 12* out. At the same time -10/0 would equate to 10* out.

They are 12 degrees out from each other in that first case. So you need to worry about how far off from the crank position the cams are and also need to worry about how far the cams are from one bank to the other. Apparently the ECU can not handle much of a discrepancy between each bank....I think 6 degrees?

[airjawed]

I just did some trial logging to try and understand the blocks from 090-094.

This is my understanding:

Block 090 will show you how much the CCT is adjusting the cam position timing for bank 1 and bank 2. When idling and low throttle this showed 0 or -1 in my case. When giving some throttle while driving this value jumped to around 20-21. This test is not done well in neutral, a road test is better because it generates more load.

Block 091 is bank 1 by itself.
Block 092 is Bank 2 by itself.

Block 093 shows how far from what is expected the cam is. In my case I had -3 and -4 in all conditions. This number did not change during any throttle inputs while driving.

Block 094 is used in Basic setting to test the system. If you rev above 2k rpm and the tensioners work then 'sys ok' appears in the last 2 windows. Can be done in neutral(no need to drive car).

So if you want to see if your CCT are working you can either do block 094 basic setting test or you can log block 090 and see actual numbers. If you want to know if something may be off with the timing belt job then look at block 093.