The number of "cranks" to start my 997.1TT is very erratic. Sometimes is starts within 1 or 2 "cranks" (a crank being what sounds like the engine turning over 1 time) and sometimes it takes 5-10 cranks. When it takes more than 1 or 2 cranks, the car immediately revs up upon starting then returns to idle speed. Is this normal? It doesn't seem to matter if the engine is warm or cold.

 

How many miles on the car? Any mods? Bad plugs?

 

Just turned 13,000 miles today. No mods. I haven't checked the plugs. Should they need replacing at 13,000 miles?

 

Shouldn't need it that soon. Maybe this?

https://www.6speedonline.com/forums/...-starting.html

 

No problems getting the engine to turn over when turning the key, just the starter has to work a little longer to get the engine going sometimes.

 

My '07 does the same thing. It is odd, but it has done it forever.

 

Common issue, whenever I notice mine cranking excessively, I turn the key off and restart it in order to avoid those hi-rpm cold starts.

 

TT there is a cure for the high RPM starts. Mine hasn't done it ever since being fixed late last year. Chances are the problem the op is experiencing may have something to do with it.

 

Spd21
What's the fix?
C

 

Had a similar issue was the fault of a dying battery. Replaced the battery and it was back to normal.

Not sure if its the same in your case or not, but could be depending on how long the original battery has been in there.

 

Battery was replaced in December '10.

speed21, what was the fix for your car?

 

I started a thread on this a while back now asking about this problem so i'll start a new thread for the benefit of all members that may not have read this post over here.

TT and ohsix, as is always the case, there is a reason behind everything. The exact cause of this problem is actually an incorrect gap between the the crank sensor and the passing marker....as it rotates past. The sensor is not within the set tolerance. An inherent assembly issue.

As you may know the ecu must read all sensors the moment the ignition key is turned and the starter motor begins to rotate the crankshaft. Voltage levels won't reach system requirements until the engine actually "fires up" so when the voltage is slightly down, as it often is after a period of being stationary, the sensor struggles to register the marker due to the incorrect gapping.

These occasions of spiking and, the frequency of these "rev up" spikes are often determined by how far away the marker is from the sensor once the engine is switched off. A weaker battery can also add to this.

For eg. If the marker has rotated just passed the sensor after the engine has stopped rotating, then upon restart, the starter motor must rotate the crank further for the marker to come back around past the sensor again. So, if the sensor is unable to read the marker due to incorrect gap (combined with the lower voltage) the engine may sometimes continue to rotate until the ecu can determine a start up ignition environment. The weaker the power the more rotations are likely to occur but once the ECU allows ignition the engine will fire up, the revs will momentarily spike, voltage is then restored to correct levels and then the ECU re registers the correct position of the crank sensor and returning the rpm to correct idle speed.....all happening within a split second.

Hope that last edit makes better sense. Sorry i was rushed before due to my late response to your earlier requests

Now to the fix. You're not going to like it. Gearbox must come off to access the sensor.....adjust sensor so it is gapped within the specified tolerance....gearbox back on again etc . Probably best to do this when doing your clutch. You may be able to get P to fix it if it is happening all the time but that may very well depend on how far out of warranty you are, and the relationship you have with your dealer. Some cars can be worse than others and this is usually determined by just how far out of tolerance the sensor was installed to begin with....along with other factors such as the battery strength and condition. Its just a guess but i think P figures that unless the problem is going to cause engine failure within warranty then they have little motivation to go to the trouble and expense of fixing it. Plus the cure isn't that old so most dealers may not be aware of it.....although i am privy to the TSB number.

And the smoking after every odd start up....... That one is shaping up to be a sequel .

 

Very very common. Yet fixable.This has been an unresolved issue amongst many owners for a very long time....in fact up until this very post i think .

You will find this problem doesnt exist in the latest cars. But it is fixable.

The weaker the battery the worse this problem can be because the sensor relies on power and signal strength to send the information to the ECU.