E-hybrid issue (cold engine start jerk/hesitation problem)
05-25-2021, 03:39 AM
#1
3rd Gear
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E-hybrid issue (cold engine start jerk/hesitation problem)
I would like to say hello to the community first 
Posting this also in panamera technical discussion area although I have 2016 cayenne e-hybrid , if someone had problem like this and can help.
Very first engine cold start, when in transition from pure electric drive to combination with inetrnal combustion engine, when the combustion engine kicks in the car jerks/hesitate (for about 2 seconds)... so the initial cold engine start is not smooth and engine feels like it is suffocating and has no air for a second or two . Also for 10-20 seconds after engine start when accelerating it feels like the engine is a little misfiring, but this is really barely noticeable. No DTC codes in the ECU/DME. Anyone experienced issue like this?
Car milleage 100k miles (about 162000km)
Official Porsche dealer says everything is OK and they don't detect any issue.
Checked:
-intake ports - carbon buildup on intake valves -everything quite clean and OK
-changed brake fluid and hybrid cluth fluid and done bleeding and adaptation with diagnostics - much smoother combustion engine engagement, but still feels the same about that 2 second suffocation feeling of engine start up.
My suspections of possible causes:
-clogged secondary air system in cylinder heads? I have no DTC in memory, so I would like to ask owners who had problems with secondary air if they notice any other previous symptoms before engine check light appeared?
-chain tensioner (when I force cold engine start with hood open I hear chain ratle - known issue with this engines) so rattle is heard for second or two, maybe is this connected to the main problem? Could be timing issue because of leaking oil out of chain tensioner overnight?
If I force start engine, let it run 5 seconds stationary, then turn off, then go on the road in normal hybrid mode there is no more jerk/hesitation at combustion engine engagement.
I will be grateful for any help/suggestion.
Posting this also in panamera technical discussion area although I have 2016 cayenne e-hybrid , if someone had problem like this and can help.
Very first engine cold start, when in transition from pure electric drive to combination with inetrnal combustion engine, when the combustion engine kicks in the car jerks/hesitate (for about 2 seconds)... so the initial cold engine start is not smooth and engine feels like it is suffocating and has no air for a second or two . Also for 10-20 seconds after engine start when accelerating it feels like the engine is a little misfiring, but this is really barely noticeable. No DTC codes in the ECU/DME. Anyone experienced issue like this?
Car milleage 100k miles (about 162000km)
Official Porsche dealer says everything is OK and they don't detect any issue.
Checked:
-intake ports - carbon buildup on intake valves -everything quite clean and OK
-changed brake fluid and hybrid cluth fluid and done bleeding and adaptation with diagnostics - much smoother combustion engine engagement, but still feels the same about that 2 second suffocation feeling of engine start up.
My suspections of possible causes:
-clogged secondary air system in cylinder heads? I have no DTC in memory, so I would like to ask owners who had problems with secondary air if they notice any other previous symptoms before engine check light appeared?
-chain tensioner (when I force cold engine start with hood open I hear chain ratle - known issue with this engines) so rattle is heard for second or two, maybe is this connected to the main problem? Could be timing issue because of leaking oil out of chain tensioner overnight?
If I force start engine, let it run 5 seconds stationary, then turn off, then go on the road in normal hybrid mode there is no more jerk/hesitation at combustion engine engagement.
I will be grateful for any help/suggestion.
05-26-2021, 12:21 AM
#2
I have noticed my Turbo S hybrid jerking some at idle, in e or hybrid mode, if that helps