Kevin

It's almost everyday now that I mention in an email or phone call.

Replace the wideband O2's sensors at 50K miles or 10 years...

Replace the MAF sensor every 3 to 4 years..

Kevin

Here is a good article... It sheds some light on what is happening on cold start.

http://www.pierburg-service.de/ximag...106_en_web.pdf

up4speed

Thanks for the info Kevin.
If the throttle body cleaning didn't fix the problem, I will look into the MAF and o2 sensor replacement. Do I also need to do the downstream sensors, or just the upstream sensors?

Macster

Don't use oil or grease on the hoses. Use plain water.

Varying RPM is not what I observe with my Turbo upon any start. The idle is a bit rough, a bit raw, but the idle speed is while elevated (~1K) it is steady until after a bit of idling the idle speed slows to just above the normal hot idle speed. The idle is a bit high yet as the engine is still pretty cold.

There could be an intake air leak. If you have been at the intake system that's always a possibility. Last thing touched, first thing suspected.

You mention a tune. Tunes are "hard" on plug and make more demands on coils and even the MAF. The O2 sensors are exposed to hotter temps and while they are designed for this they can and will suffer degradation.

Last Jan. I had to O2 sensors in my stock 2003 Turbo replaced at 132K miles. The engine's behavior was a bit improved. Not oodles but I noticed it. Oh I had the sensors replaced because of a CEL once in awhile. There were as best I could tell no other symptoms. But I wanted to get the car smog checked and I didn't want any risk of the car failing. Besides I figured at 132K miles I got my money's worth. The original sensors in my Boxster didn't even make it to 100K miles.

Could be your Turbo's engine is in need of a tune up. Kevin's advice to replace the sensors (I'd replace all 4 rather than just the wide band ones) and even the MAF -- mine's original but my engine's stock -- could be just the ticket. Along with plugs of course.

And maybe coils.

Regarding coils: My Turbo engine once in a while -- when left out in the rain, or heavy fog, will misfire upon cold start. Misfire with a CEL, too, not just sound/feel like it is misfiring. It does not misfire at any other time. Next time I have the car in for something I'm having the coils replaced.

up4speed

I started it this morning. Unfortunately, there is no change from cleaning the throttle body (as I suspected).

I'm starting to wonder if it is just a characteristic to this engine?

Take a look at the video and note the tachometer and when I feel the roughness. Now that I really paid attention, it's not so much a "lumpy" idle, or one that is "missing". I think it's more of a high frequency vibration. It also never has a problem running smooth and strong when I give it some throttle.

Is this normal for these cars? I might need a guy who has a lot of experience with 911 TT to look at it before I drive myself nuts chasing something that's "normal"! LOL

https://www.youtube.com/watch?v=TvuV...ature=youtu.be

rmc1148

It doesn't seem that rough but hard to tell without being in drivers seat. If its in the budget have a reputable shop take a look and save the headaches/worry about if its right or not.

Dock

Can't actually hear the engine very well in that video.

Maybe you can have someone video tape from the back of the car when you cold start it.

up4speed

It really isn't too bad, but it also seems worse than what I would consider "normal". I think you are right, I should probably let someone who is experienced with these cars take a look.

The sound is fine, you will not hear anything wrong with the sound other than that initial dip for a split second when it is first started. It is visible in the video by watching the tach. I just brushed that off as the car finding it's idle while processing info from the sensors. It's not like it misfires or anything like that. It sounds perfectly smooth, it's just that the car physically shakes/vibrates. it feels like an unbalanced, or very unrefined engine while the issue is happening.

Dock

Where do you live?

up4speed

Long Island, NY

Dock

There has to be someone from this Forum who is close enough to you, and can drop by for a cold start assessment of your car.

up4speed

I actually have a friend with a 2004 cabriolet, but he didn't seem to think his was the same. I'll have to pay him a visit.

up4speed

A little more info today.

I noticed that under light to moderate throttle, the engine will sometimes surge when it first switches to 4th gear (Tiptronic). It may actually do a little surge in 3rd right before the gear change too. It did it a few times today during a 30 mile ride. I have definitely felt this in the past, but I ignored it since it is usually VERY slight and the car doesn't miss and it runs strong and it goes away if I give it a little less or more throttle. I was also suspect that it may be a tune issue. For instance, I'm wondering if that is the point where the vario cam kicks in or something like that?


Also, I noticed that if I'm in neutral and hold the throttle at about 1,800 rpm's, I get a good amount of vibration that is very noticeable. I assume that if it's not normal for this car. Another important bit that I forgot. If I'm not completely stopped and I try to put transmission in 1st, I get a pronounced bang when it goes into gear. I'm guessing motor mounts as was suggested (or transmission mount)?

I can't imagine any real problem with a car that has only 19,000 miles.

rmc1148

You need to have a shop or someone with experience take a look, I'm sure its something minor. Get it checked out and enjoy your ride.

Dock

I'd take it to a mechanic.