Warm idle problem 944S2

[guygep]

Another issue, I red alot on many forums about this common problem, but before changing the expensive ICV I need some opinions...

Car was back from garage and have a new clutch.

Drove home, and before putting the car in the garage, car almost stall with a rev bouncing up and down, oil pressure falling down.

1. My needle on the temp gauge is very low in the dashboard, below the 1rst mark, and it is 93F outside when I drive the car. I had to keep the rev up or the engine would die

2. Once back home, I revved the engine until the needle went all the way up, and I could hear the cooling fan functionning ; once the cooling fan started, the rev was consistant, with the needle all way up, no stall problem

3. Can it be a bad coolant temperature sensor faulting the reading of the MAF??? or is it anither cause of a bad ICV again?

[John_AZ]

Originally Posted by guygep

Car was back from garage and have a new clutch.

If you took the car into the garage and the idle was OK,

the shop may have not connected the grounds tight enough or a connection is loose.

That is where I would begin.

John

[guygep]

Whicg ground?
They told me the only unplug a connector underneath the car, which one would it be?
The car runs fine on cold start-up, the **(&&*??%* idle problem only comes when the car is warm...

[John_AZ]

Your 3L 944S2 has a pair of reference sensors on top of the bell housing that have to be removed with a clutch job.

It could be a bad sensor, connection, a negative battery connection on top of the engine, a O2 sensor connection they messed with. Try disconnecting the O2 sensor and see if the idle improves-if it is used in in Candiac.

Just a few ideas.

GL
John

[guygep]

OK. Spoke with the mechanic, they told me the sensor was put back in plce properly.
Is it accessible below the car this sensor?
The O2, if I remove it, will it trigger a CEL?

[John_AZ]

Probably...

Occassional "Check Engine" light and rough running upon startup - Page 2 - Rennlist Discussion Forums

Reference sensors are on top of the engine at the firewall.

Is there another Porsche shop in town?

John

[guygep]

NOpe, all shops are overbooked.

I have order a new coolant temp sensor and will change it tomorrow.
Will see from there.

Will also try to remove the ICV (hard to reach) and clean it also.

As far as the mproperly gapped (0.8 mm from flywheel), should it be malfunctionning even at the cold start?

[mhr]

If you think it is the ICV (which doesn't sound like) unplug it and see if the problem goes away. It will cause some cold idle problems but you will know if ICV.

Hope to see you on the road!

[John_AZ]

Why are you focusing on the coolant temp sensor?

The DME engine temp sensor is more likely the problem.

Pelican Parts - Product Information: 944-606-125-00-M14

John

[mhr]

Originally Posted by guygep

Will also try to remove the ICV (hard to reach) and clean it also.

before you remove it just try unplugging it.

Removing it is easy. Its getting it back in that it a PITA.

[guygep]

Originally Posted by John_AZ

Unless George-944Ecology can correct me again,
why are you focusing on the coolant temp sensor?

The DME engine temp sensor is more likely the problem.

Pelican Parts - Product Information: 944-606-125-00-M14

John

sorry, this what I ordered, the ones that goes underneath the intake plenum? Difficult to change?

[guygep]

What does the sensor does on the bell housing?

My car was runing fine before the clutch change...

[guygep]

I changed the temp ensor, still same problem, wants to stall, but the rev is not bumping that much anymoreé

Could it be the DME relay?

[mhr]

I have a spare if u want to test. Will be home (ddo) tomorrow evening

[guygep]

PM sent

[C ANDERSON]

Check the hall sensor at the cam cover make sure its plugged in good and connector hasn't fallen apart. Also again check the grounds at the bell housing rear of engine. good place for a problem since the bell housing was off to do the clutch. I would also check the reference sensor plug at the rear and the plug . Pull the sensor out make sure that there is no material on the end of it as its magnetic . Go to Clarks Garage and do the setting for the reference sensor. The S2 has a sleeve in the bracket that has to come out to take the bell housing off. May Had problems with that when doing clutch and removed the sensor bracket and didn't get the sensor set correctly afterwards.
Clifton

[guygep]

OK, I will also check the O2 conenctor just in case..

where the hell can I see that sensor and connector«?? It is so cramped there.. From the top or do I need to go underneath the car?

[C ANDERSON]

The 02 is just behind the intake on a bracket . its the round one that is clipped onto a plastic holder unplug it to see if the problem goes away. The hall sensor plug is on the side of the belt cover by dist cap toward passenger side check to make sure its plugged in and that the plug is not falling apart . The reference sensor is the hardest to get to its on a bracket at the bell housing the bracket attaches to the block and the senor goes thru the bell housing S2 has one there . If you pull it make sure you don't let the bolt fall into the TDC window in the bell housing or you'll be having the clutch labor done again, check the connector for the reference sensor its on the same bracket as 02 but is the flat one with 3 wires. They also fall apart and short giving problems.

Since a clutch was just done I would be looking at every thing touched during the clutch job especially grounds and the reference sensor on the bell housing.

Clifton

[guygep]

OK, thanks Clifton. Do I need to remove the completely the sensor on the carnk or just check the connectors? I' m not a big mechanic fan....

[C ANDERSON]

just look at the connectors real good make sure there not crumbling goes for the rear and the one at the front by the cam. the one by the cam cannot be easily changed have to remove the rear cover so belt as well. the rear reference sensor you can remove to make sure there is no metal on the bottom of the sensor but since a clutch was done concerned that they may have removed the bracket and did not set the gap back correctly and they didn't its a real pain to do with bell housing and all back on. Clarks Garage has some good pics and procedures on this however it is all for non S2 so only one sensor on rear of yours . Still procedures apply.

Since the clutch was done my opinion still goes towards stuff at the rear of engine again grounds are very likely . the rear reference sensor it most likely would not run at all.
02 can do what you described and just disconnecting will make it stop. when you said fans came on and it stopped acting up makes me thing more toward a ground or maybe the ICV under the intake . But lets look at stuff neat the clutch first.

Clifton