Hello Everyone,

 

Im really hoping that a technical expert is able to answer this question. For the 1.2 tsi CBZB engine, stretched timing chains is an issue. And the timing between the crankshaft and the camshaft is depending on the chain has the correct length. I was told by skoda that the ecu is monitoring the phase between the 2 shafts, and if its to mych out of phase, it will turn on engine light.

BUT im also told that the engine in fact is capable of running pretty normal even if chain has jumped 1 or 2 teeths !!!

I have been looking all available measurement points in the engine ecu, and the only thing i find which obvious relates to this, is

270 X_Intake_camshaft_signaledge_position_adapted_value_Edge2 to Edge8. I think it says something about how much the ignition should be adjusted, by comparing the signals from the crank and camshaft. But whst tdoes the values really say ? In general poeple on the net agree that bigger vaues are not good.

 

My chain has just been measured by skoda, and it is NOT too long.

I had another car with the same CBZB engine 1.2 tsi, wich were also mesured chain was NOT to long, also attached.

Obviously there is difference in how much addaptation needed for the two engines, Im just sooo courious what this adaptation means ?

For my engine it says in another measurement that advance timing for cylinder 1 is 8.5 degrees, and the adaptation values is as follows:

 

I think the stretched chain was an issue on pre 2012 models, since then a new chain and new pulleys have been fitted (and eventually a change to a belt).  From what I read, is that the timing being out prematurely kills the pulleys which consequently fails the chain.  Not sure if that answers the question though.

On 05/09/2020 at 15:26, mikkelvitus said:

 

 

Doesn't the 1.2 tsi have just have a plastic timing chain cover you can pop off to check for tension & check the sprockets for wear and tear.

 

If its 8.5 degree's then your vcds logs looks to say your timing is out its hit 9.0625 degree's which would out of your threshold indicating your timing is out. I'm unsure of the timing values on 1.2 tsi however vw's I've had in the past were 5 and-5 degree limits.

 

I would be tempted to pop of the camshaft covers and check the camshaft alignment is correct, check chain tension and check sprockets for wear and tear. Your chain should never be allowed  jump teeth unless there is an issue with the ,chain,tensioner or cams and therefor throwing your timing out.

 

I've never seen a warning light for timing issues or stretched chain, usually its audible and you feel the chain rattling  through the engine, Misfiring is more likely to bring on a warning light If caused by the chain.

 

Hope this helps, unfortunately I've never had the chance to work on a 1.2 tsi. 

 

 

 

 

 

Edited 1 October, 20205 yr by Mickmartin

Chain stretch is normal, the tensioner is designed to take up the slack as this happens, even a stretched chain will only alter timing by a fraction, the problem is some tensioner mechanisms allowed the chain to get too loose which caused it to jump teeth.

 

You don't have anything to worry about until you can actually hear the chain rattling, the readings you provide prove that the chain has not jumped.

1 hour ago, sepulchrave said:

Chain stretch is normal, the tensioner is designed to take up the slack as this happens, even a stretched chain will only alter timing by a fraction, the problem is some tensioner mechanisms allowed the chain to get too loose which caused it to jump teeth.

 

You don't have anything to worry about until you can actually hear the chain rattling, the readings you provide prove that the chain has not jumped.

Thanks for telling me that - but can you also tell me what these adaptation values in degrees is reference to ?

1 hour ago, mikkelvitus said:

Thanks for telling me that - but can you also tell me what these adaptation values in degrees is reference to ?

 

Since the sample rate for the measuring block is half a second it suggests that the measured value is fluctuating between 7 and 9 degrees advance with a mean variance of half a degree which suggests your camchain is not very loose at all. Minimal scatter.

48 minutes ago, sepulchrave said:

 

Since the sample rate for the measuring block is half a second it suggests that the measured value is fluctuating between 7 and 9 degrees advance with a mean variance of half a degree which suggests your camchain is not very loose at all. Minimal scatter.

But those values are more or less static.
They dont change when reving engine, so the adaptation is like very slow changing, which also seems right as the chain elongates very slowly.
But whar i would like to know, is like, what is "intake_camshaft_adaptation value_signaledge 2" = 5 degrees. Is that how far from crankshaft reference position that this mark is on the camshaft ? But then it makes no sense that signaledge_3 is only 0.5 degrees.

I would really like to know what im reading here ?

The output from the cam position sensor is a square waveform so that makes sense.

5 minutes ago, sepulchrave said:

The output from the cam position sensor is a square waveform so that makes sense.

Yes it looks like this and the signaledges must come from the camshaft sensor - but pls. clarify what the amount of degrees referring to ?
 

Generally on fixed timing it refers to an inlet valve lift of 1mm in degrees before TDC, this is known as inlet cam advance, obviously on the later engine this value changes dynamically due to the VVT system on the inlet cam.

I don't know what the exact specification is for that particular engine before you ask, my experience is with vernier pulleys on high performance engines where timing cams accurately requires a degree wheel fitted to the crank and a dial gauge riding on the valve spring retainer.

I'm very curious to know as well what range is safe for a 1.2 TSI (CBZB) engine?

Can't find any leads online.. :(

On 21/06/2025 at 11:36, wd73 said:

I'm very curious to know as well what range is safe for a 1.2 TSI (CBZB) engine?

Can't find any leads online.. :(

Hi, in this video you can see how to mesure it via vcds: https://www.youtube.com/watch?v=1e9imH68urw

the parameter are:

• 0° to -2° new - still good green zone

• -2° to -4° to keep monitored yellow zone

• -5° or more red zone the chain needs to be replaced even if there isn't any rattling noise. 

26 minutes ago, Jack25 said:

Hi, in this video you can see how to mesure it via vcds: https://www.youtube.com/watch?v=1e9imH68urw

the parameter are:

• 0° to -2° new - still good green zone

• -2° to -4° to keep monitored yellow zone

• -5° or more red zone the chain needs to be replaced even if there isn't any rattling noise. 

Thanks, but your video is not a tsi engine with SIMOS ECU.

I dont think that bank 93 in SIMOS has that information ?

2 hours ago, mikkelvitus said:

Thanks, but your video is not a tsi engine with SIMOS ECU.

I dont think that bank 93 in SIMOS has that information ?

My bad you need to go in engine-advanced measure search for timing deviation after chain replacement (on SIMOS ECU) I have a 2.25° after 98k km with oil change every 9-10k km

My version of SIMOS is 10.10 wich to my understanding was the first version - and also a version where there is no option to reset timing enhancements values when you replace the chain.

To my understanding there also is no dedicated field where the timing deviation is recorded, other than those 7 parameters i have shown in the top of this post - wich if they somehow could be intrepreted, should say something about the rotation timing of the camshaft related to the crankshaft.

The problem is that the values are jibberish, and just some entrys of some degrees - wich all is related, but i dont know how.

I bet that the SIMOS you are showing data from has version 10.20 or so ?

3 hours ago, mikkelvitus said:

My version of SIMOS is 10.10 wich to my understanding was the first version - and also a version where there is no option to reset timing enhancements values when you replace the chain.

To my understanding there also is no dedicated field where the timing deviation is recorded, other than those 7 parameters i have shown in the top of this post - wich if they somehow could be intrepreted, should say something about the rotation timing of the camshaft related to the crankshaft.

The problem is that the values are jibberish, and just some entrys of some degrees - wich all is related, but i dont know how.

I bet that the SIMOS you are showing data from has version 10.20 or so ?

I’m sorry before I was quite in a rush and I’ve just enabled all the parameter I’ve found searching “timing” and also the engine wasn’t running. I will try again tomorrow evening

(I have a 1.2 tsi (originally) 86 bhp Fabia production year around 2011-2012 (I suspect by the label in the panels) but registered in 2013 I will also check the SIMOS version and let you know.

For the chain stretch adaptation I believe is automatic when you replace the timing chain because the sensor will report to the ecu a different degree reading on the stretch value.

41 minutes ago, Jack25 said:

For the chain stretch adaptation I believe is automatic when you replace the timing chain because the sensor will report to the ecu a different degree reading on the stretch value.

In the first vesion of simos (10.10) there is no option to reset timing adaptation values. But the latter versions (10.20 ->) there is an option to reset adaptation vlues when you do a chain replacement.