initial start has a rough sound for 1 second
07-08-2021, 02:20 PM
#1
4th Gear
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initial start has a rough sound for 1 second
Sometimes when I start my 2007 Cayman S it seems to have a hard mechanical initial hit like the first piston has single misfire. (no CEL)
It always starts quickly and goes away instantly.
I am not applying any throttle prior to cranking, however it seems not to happen when I use a little throttle.
Anyone else have this happen? Should you use a little throttle on cranking?
It always starts quickly and goes away instantly.
I am not applying any throttle prior to cranking, however it seems not to happen when I use a little throttle.
Anyone else have this happen? Should you use a little throttle on cranking?
07-08-2021, 03:32 PM
#2
i doubt if the ECU/EMU/EMU/etc., etc., is affected by accelerator pedal movement before it deems the car to have started, but i could be wrong once again today. 
Last edited by hueyhoolihan; 07-08-2021 at 03:34 PM.
07-09-2021, 10:12 AM
#3
Instructor
Perhaps check tensioner?
I am chasing a bank 1 cam deviation issue at the moment which I believe is down to a failing bank 1 tensioner. In my research on this a hard mechanical noise on startup Is a symptom of a failing tensioner and likely the bank 1 tensioner. Basically the bank 1 tensioner is positioned upside down so if the seals or something inside are dying it doesn’t maintain pressure when the engine is off. Therefore when you start the car there’s no tension on the chain and the noise you hear is the chain slapping the chain guide until the tensioner pumps back up after a moment or so of oil flow.
In my case, I bought my car from auction a couple of months ago so I don’t know how long it sat unused for (this can lead to premature failure of the tensioner). After completing maintenance and replacing /fixing a number of items that needed addressing prior to getting it inspected and registered I gingerly drove it around the neighborhood to get everything up to temperature and see what codes if anything the computer wanted to spit out. I’m using an iCarsoft POR2.0 unit and looking at the engine data it was showing a deviation in cam timing for Bank 1 in comparison to Bank 2, car runs nice and smoothly though, I wouldn’t have noticed without the diagnostic sensor data.
Research showed that I might need to replace the tensioners/guides/chains etc depending on how long this has been happening and what I needed to do was drop the oil pan to look for plastic (bits of the chain guide). Big chunks would mean needing to replace them (duh). Luckily for me there was no pieces of plastic (or metal for that matter) so I believe the tensioner is failing but only very recently. Should have a new one in the next couple of days.
Cheers,
Julian
In my case, I bought my car from auction a couple of months ago so I don’t know how long it sat unused for (this can lead to premature failure of the tensioner). After completing maintenance and replacing /fixing a number of items that needed addressing prior to getting it inspected and registered I gingerly drove it around the neighborhood to get everything up to temperature and see what codes if anything the computer wanted to spit out. I’m using an iCarsoft POR2.0 unit and looking at the engine data it was showing a deviation in cam timing for Bank 1 in comparison to Bank 2, car runs nice and smoothly though, I wouldn’t have noticed without the diagnostic sensor data.
Research showed that I might need to replace the tensioners/guides/chains etc depending on how long this has been happening and what I needed to do was drop the oil pan to look for plastic (bits of the chain guide). Big chunks would mean needing to replace them (duh). Luckily for me there was no pieces of plastic (or metal for that matter) so I believe the tensioner is failing but only very recently. Should have a new one in the next couple of days.
Cheers,
Julian
