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VVT Monitor Banks 1 and 2 Fluctuation from Pass to Fail
Just picked up the iCarsoft II diagnostics tool to aid in future troubleshooting. Was just scrolling through all of the information I could view when I noticed the failures for VVT test. The value fluctuates between passing and failing. Is this an early sign of VVT failure or chain tensioner failure?
I couldn't find any other test through the 40 or so I clicked through that were fails. No misfires, if I remember correctly, under high neutral revs I saw timing upwards of 30 degrees.
When you did the test, was engine coolant temp above 85C already ?
Yes, fluctuations between 85-88C. I don't remember oil temp. I can perform again when car has been driven for over 10 minutes, if that would yield proper diagnostic results
My icarsoft is V2.0 and is not bidirectional, I can't do test, only read and delete DTC.
Under Xentry, we can test VVT actuators but there is no pass of fail. Because it is a simple maximum advance or retard depending which cam you are testing. Its an ON-OFF test so to speak.
NOTE: Alebit my engine is M276 3.0 and yours is a 3.5L assumed as M276 , the VVT system is the same.
If VVT fail, DTC is for sure triggered because if I remember correctly, 5 degrees drift is maximum.
NOTE FOR TEST : Some are bidirectional via Xentry, some are hands on we do physical check and guidance provided.
IF these above values drift too much, DTC is guaranteed. 5 degrees drift is equal to 1 timing chain tooth jump.
Take photo of your icarsoft test page, I am curious about it.
My icarsoft is V2.0 and is not bidirectional, I can't do test, only read and delete DTC.
Under Xentry, we can test VVT actuators but there is no pass of fail. Because it is a simple maximum advance or retard depending which cam you are testing. Its an ON-OFF test so to speak.
NOTE: Alebit my engine is M276 3.0 and yours is a 3.5L assumed as M276 , the VVT system is the same.
If VVT fail, DTC is for sure triggered because if I remember correctly, 5 degrees drift is maximum.
NOTE FOR TEST : Some are bidirectional via Xentry, some are hands on we do physical check and guidance provided.
IF these above values drift too much, DTC is guaranteed. 5 degrees drift is equal to 1 timing chain tooth jump.
Take photo of your icarsoft test page, I am curious about it.
Thank you for the detailed response. Unfortunately, I don't have Xentry and could not find anything through all the screens that I clicked through that was related to camshaft position. Below are the pictures of all of the menus that I have access to. Perhaps you could be of some guidance? Much appreciated.
OBDII and Benz are the menus that give data relating to my car Page 1 Inside of OBDII Menu Page 2 Inside of OBDII Menu Page inside of BENZ Menu Inside of BENZ Diagnose, preceeds listings Attempted to enter ECM menu and am met with this error. Received this error for other menus aswell. Not sure what the specific reason for no entry is, since I have no experience with this Page 1 Benz Diagnose PG 2 Couldn't see any of this relating to engine values, nothing in instrument cluster. PG 3 All of these seemed useless This and the preceeding image was the only remotely close thing I could find. Same as previous image with different timing advance. Advance degree within normal specs?
Dynamically ignition timing can also change from input of the knock sensors to the engine computer telling knock exist and timing to be retarded. Engine Load will effect too.
This is a good explanation on Ignition timing and knock sensor
Wideband lambda sensor ( Bank 1 no 1 and Bank 1 no 2 oxtgen sensor ) also do last second fine tuning. Our engine combustion management is very fast and complex.
Ignition key need to be at position 2 ( ready to crank, dashboard all lights up or Engine OFF Key ON EOKO some people call it ) for ECM to be able to communicate with scanner, some modules do not need up to key position 2.
This is my engine from cold start 29 celcius and 211 seconds into it, see the Ignition timing.
When engine still cold, the timing get retarded because engine need to be at encriched fuel mix and cylinder wall still cool, so flame can't propagate well, hence timing can not be too advance.
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