Gonzo911

Greetings all. Last week I had the 60K service done by my Indy on my MY03 Cab. Oil change, plugs, coils. I only have 52k on the car, but no good history since I have only had the car 5 months, so I wanted to make sure everything was up to speed (so to speak).

Prior to getting the service done, I generally would sense the upshift (gears 2-4) at around 4200rpm. Now, after the service, it is more like 5500 rpm. Although the acceleration is much smoother, I don't get that "push you back in your seat" feeling I used to get, especially in 3rd gear (although 2nd definitely has more bite).

Thoughts?

No HTwo O

Tip or manual?

It may just need time to re-learn your driving style.

Gonzo911

Sorry, 6-spd.

Ahsai

Do you know what kind of plugs they put in? Assuming it's genuine Porsche coils, can't think of anything obvious...

No HTwo O

You need to explain this better. You make it sound like the car is controlling the shift points, not you.

Maybe one of the coil packs are now cracked, and you are running on 5 cylinders.

911SLOW

Wash and wax it. It always feels faster afterwards. : )

Gonzo911

Slow: I think I read that in a Rennlist post somewhere! Washed and waxed Sunday morning.

No H2o: I guess what I am feeling is that the car just doesn't jump through the gears like it did before, less torque might be a better explanation although the accleration is smoother it is not as dynamic. Something definitely feels different.

francars

Did you take car to dealer or Porsche Indy?
If you feel something is wrong you might want to call the person/shop who did the 60k service.

Macster

Various things are possible.

I'll cover them in no particular order:

Indy used wrong plugs or sub-par coils. There is no misfire or the CEL would be on. Thus this sort of eliminates the coils.

If the plugs are questionable what could be happening is the DME is detecting detonation signals from the knock sensors and dialing back timing at various well times. This can make an engine feel flat.

Or the DME has its learned adaptations cleared. This happens when the error codes are erased, even if there are no active error codes (the CEL is dark).

Sometimes in a shop the codes are erased even though there is no CEL. (Dealer service techs avoid clearing the CEL unless there's a definite need to clear it.)

If the CEL was cleared and the adaptations erased you will have to drive the car some so the DME can adapt once again to the engine's particular needs.

Depending upon various factors the engine can feel a bit off its feed until this happens.

Or, the car spent a bit of time idling, being treated to short (very short) trips around/about the shop/parking lot (pulling the car into/out of service bays) and the DME adaptation reflects this.

(Modern cars that are taken to drag strip get a 1st run that in layman's terms blows the cobwebs out of the engine. In more precise terms the first run down the strip causes the DME is relearn new adaptations from among other things more aggressive acceleration, higher engine loads, and higher rpms and the engine's performance is markedly better after the 1st run.)

In short, the engine may just need a brisk romp (after being fully warmed up of course) to perk it up.

However, I would advise you to if at all possible to eliminate other possible causes -- like plugs/coils as I touched upon above -- because in extreme cases engine damage from too hot or wrong reach plugs can occur.

Check back with the indy shop and get the input from its staff.

If you get told to 'drive like you stole it'... well maybe you need to give the engine the romp.

But you need to hear this from them not me.

Sincerely,

Macster.

Speedyellow993

Did they use the correct grade oil?

Macster

I think I want to change my mind.

Thinking about this some more I've never noticed any change in performance from my Boxster coming back from any service. I have never had to replace the coils (and they have over 250K miles on them) but the plugs have been changed along with of course the engine air filter. (There is no serviceable fuel filter.)

Also, I have certainly erased codes in my Boxster often enough, and while I notice a bit of rougher running upon the next cold engine start beyond that -- and it is slight -- if you gave me a blind test with the codes erased or not erased I couldn't tell it from the way the engine behaves.

Same for my Turbo, which has had one plug change but is on its original coils with over 86K miles on them. I've erased codes (even though none were active or pending) just to see how the engine reacted and the same thing applies to the Turbo engine. Unless I knew the codes were cleared I couldn't tell it from the way the engine behaves.

For both cars the things that affect the engines' performance -- based on a seat of the pants dyno, mine -- is climate (cold but not real real code air and dry air) or an exceptionally good tank of gas or more likely a good tank of gas after burning through a tank of less than good gas (discount gas station gas) and a good long drive, of around 40 or more miles at highway (or higher) speeds.

For example: I've been driving around 120 miles per day (alternating between cars) this last couple of weeks the last 50 miles non-stop and at highway speeds and both cars have perked up some from the extra driving.)

My revised reply is you need to get some answers from the last people who worked on your car.

Sincerely,

Macster.

Pac996

Macster has a very good point that is probably the cause. Your DME / computer needs to know what its doing by knowing what it is dealing with. So brisk running and time will get it to know whats the right timing and such to keep things proper. The car reads a lot of specs O2 and such to have the proper feeding of fuel and air. Dinner time or I'd drag on.