Turbo Lag

[Amrit Rahal]

Hi all

 

Fairly new to ownership of new to me Cayenne 958 turbo 2014 

 

I have had various issues with it being sluggish and miss firing since i have had it, garage diagnosed it as racechip which was interfering with the map sensor readings and causing it to missfire. unplugging racechip bits in engine bay meant no more sluggish drive but it is still causing me some headaches

 

1 - randomly it throws PSM error and sometimes EML, read codes and it doesnt point to any wheel speed sensors etc like it normally would but suggest misfire on cylinder 4! i have now ordered new coil to try see if this is failing coilpack. when i switch car off and on, errors go away and sometimes doesnt reappear for days! any thoughts please?

 

2 - this could just be placebo effect but i have moved on from a 5.5l supercharged AMG to cayenne and find sometimes there is a good few seconds delay on getting power. i have it booked for ECU/TCU map next month but wanted to understand what everyone sees on dash on boost guage when you are going full WOT? i get 0.7 on normal mode and 0.8 on sport mode. seems very low and also as soon as i let go of accelerator it drops straight away and sometimes in random pattern. i have looked into replacement divertor valves as its original ones tend to loose boost really easy. Thoughts?

 

Car is very low mileage and seems like had harder life in past where it was probably parked up for good few months at a time. I have had a full service done few months back and they didnt find anything obvious at the time but didnt change plugs as were only done last year or so and obv coil packs are maybe original. Does anyone have any suggestions on which route i should go down to get me fall in love with performance of this car?

 

Thank you 

[JE 17]

Sorry to hear you are having this trouble. I've been through a few things on my 2011 version, but I love driving it almost over my 911 or Boxster!

I don't find a lot of lag, but then it's not a car and it's fairly heavy. A few seconds delay? I would be looking for leaks in the turbo plumbing--or a bad turbo or two. Also, a supercharged engine is always going to be more immediate on boost. My guage reads in pounds and I believe the most I've seen is 6 but not positive as I don't really look at that in the WOT situation: the road ahead is more important at that point!

If you are getting one coil pack, you should just replace them all to avoid chasing your tail.  As has been observed many times in many forums I follow, if one is bad more are right behind!

No pro mechanic here, but I suspect a lot of your trouble begins with that "tune." 

Edited October 30 by JE 17