Just picked up a CPO 08 TT. I noticed on first start in the morning that rpm jumps to 3,000 then immediately back to high idle (1,000) and then after about 30 seconds to 700 rpm or so. The 3,000 seems high to me - other P-cars I've had jumped to about 2,000 on first start. I've got a loud exhaust so the inital noise on start scares the kids and animals. Any thoughts on what's causing this? Thanks.

 

The rpm jump at start up happens to me some times, maybe once every 10-20 start ups or so. Not sure what caused it, but as far as I know it's pretty common.

 

The idle sequence you just described seems somewhat normal. The initial start RPM is always a bit high, although maybe not quite as high as 3000 rpm. The higher idle after that is the cold start sequence, and involves the secondary air pump and higher idle speed to assist in warming up the cat converters (aids in controlling emissions). The next step to 700 rpm is when the cold start sequence has ended and the car is at normal idle. If you listen closely you should hear the secondary air pump shut off just before the rpm drops down to normal idle.

 

Yeah, funny, mine just did this the past three start ups and now it's back to normal. I figured it was just telling me I need to blow some carbon out of it soon.

 

Mine does it as well. One remedy; it only seems to do it when the starter is cranking longer than usual, when you sense that, stop and turn the key off then restart the car as usual. The dealer has been useless on this issue.

 

I wish mine would start at 3,000 specially if i was in an underground parking, that would sound awesome.

it depends on the weather, in winter I've noticed the "loudness" start-up unlike summer where it starts at 1,400.

it's adjustable, ask the dealer ship, mine used to go down to 600 with a heavy vibrate, they adujst it to 800 and feels like Sedan when it's on Neutral.

 

In you case it seems liketoo much gas in the system right before it starts. So the engine goes to 3000 RPM and then drops back down.

 

Yours too.

 

There's nothing to adjust - the car idles just fine - immediately after start cold idle about 1100 rpms then settles into regular idle of 800 after about 30 seconds.

 

That would be my guess too.

 

I's a systemic problem with early 997 turbos, it's a very common complaint. Loud starts isn't the issue, rather sudden 3000RPMs on an ice cold engine, before the oil even hits the bearings, can't be good. I think it's an electronic issue that porsche needs to work out, supposedly '09 and up cars don't do it at all.

 

Interesting issue - I had an 07 997TT when I lived in a much colder climate (Denver) and never experienced this. Now I have an 08 in a warmer climate (Austin) and I get the initial high rpm on start. I try to keep the rpms low until the engine warms up but I have no control over the jump to 3000 rpms.

 

Mine's a 2009... one of the last 3.6's.

It only did it 3 or 4 times, and now it's back to normal. Really weird.

 

Mine ramps up there every 10 or so starts. Could be many causes but one things for sure at least, its quite common. Im not worried about it other than it pisses the neighbours off sometimes at 5.30am when I leave for an Ortega Highway run on Sundays.

 

Perfectly normal....or so P says. Shouldn't happen every start but every once or so is ok. All the time means something may not be right.....a fouled sensor or something like that.