993 varioram - constant high idle problem?
Discussion
Yes I know nobody on here reads this sort of stuff, but it might help someone one day 
I had a constant high idle, cold or warm, and couldn't find a cause.
There is plenty of info about low idle, hunting, stalling, fluctuating idle, but nothing on a constant high; mine was in the range 1200 to 1400.
There are a few internet-posts on the ECU thinking the car is still cold, or thinking the a/c is running when it isn't, but none of these matched what I was seeing - i.e. from cold. Though I was concerned that the ECU was on the way out (also check the ground wire on the ECU under the seat if you see any such problems)
(NB if anyone would like to correct my terminology on the below, do please jump in.)
I did what I could, but couldn't solve it, so I took it to my trusted Mechanic. Whilst waiting for the ancient Porsche diagnostic tool to arrive so he could check all of the sensors, he checked the ones he could, plus the ICV and electrics (which I had obviously cleaned again even though it was not that dirty), and all was ok.... but he noticed that the bottom Varioram inlet flap and actuator had an indecent covering of oil. So he took it apart.
Apparently this one is different from the others? It has a seal where the actuator rod passes through, a sort of o-ring.
Well mine had turned to stone, and was letting oil out, and was possibly letting air in as well. So the Mechanic 'made' a replacement from some new seal parts he had lying around, cleaned up and refitted.
This has certainly made a massive difference to the idle. It might not be the whole problem, as the diagnostic also noted an issue with the engine cylinder head temperature sensor, but it's now sitting at 900 ish.
I've ordered a new echt sensor anyway, but until it arrives I'm going to give the car a damn good thrashing, especially tomorrow (been too busy this w/e), and will report my findings.
Also - searching specifically on the above, I found this:
https://forums.pelicanparts.com/porsche-964-993-te...
Before
Location
After - NB the wetness is ongoing cleaning
I had a constant high idle, cold or warm, and couldn't find a cause.
There is plenty of info about low idle, hunting, stalling, fluctuating idle, but nothing on a constant high; mine was in the range 1200 to 1400.
There are a few internet-posts on the ECU thinking the car is still cold, or thinking the a/c is running when it isn't, but none of these matched what I was seeing - i.e. from cold. Though I was concerned that the ECU was on the way out (also check the ground wire on the ECU under the seat if you see any such problems)
(NB if anyone would like to correct my terminology on the below, do please jump in.)
I did what I could, but couldn't solve it, so I took it to my trusted Mechanic. Whilst waiting for the ancient Porsche diagnostic tool to arrive so he could check all of the sensors, he checked the ones he could, plus the ICV and electrics (which I had obviously cleaned again even though it was not that dirty), and all was ok.... but he noticed that the bottom Varioram inlet flap and actuator had an indecent covering of oil. So he took it apart.
Apparently this one is different from the others? It has a seal where the actuator rod passes through, a sort of o-ring.
Well mine had turned to stone, and was letting oil out, and was possibly letting air in as well. So the Mechanic 'made' a replacement from some new seal parts he had lying around, cleaned up and refitted.
This has certainly made a massive difference to the idle. It might not be the whole problem, as the diagnostic also noted an issue with the engine cylinder head temperature sensor, but it's now sitting at 900 ish.
I've ordered a new echt sensor anyway, but until it arrives I'm going to give the car a damn good thrashing, especially tomorrow (been too busy this w/e), and will report my findings.
Also - searching specifically on the above, I found this:
https://forums.pelicanparts.com/porsche-964-993-te...
Before
Location
After - NB the wetness is ongoing cleaning
Edited by Orangecurry on Sunday 19th March 20:34
Air leaks are common as these cars age. Its often the intake runner cracking or base seal leaking (where they meet the head) .The rubber connectors between the runners and the intake manifold can also go hard and leak. Any air leak after the air flow meter will cause running issues. Quite a lot of work involved changing these things unfortunately.
ras62 said:
Air leaks are common as these cars age. Its often the intake runner cracking or base seal leaking (where they meet the head) .The rubber connectors between the runners and the intake manifold can also go hard and leak. Any air leak after the air flow meter will cause running issues. Quite a lot of work involved changing these things unfortunately.
Is the above all in/above the 'top' of the engine?Yes OC. Inlet system needs to be removed. TBH it would probably be easier to do a job like this with the motor out as unlike the earlier cars the 993 uses allen key type bolts which are often seized/difficult to remove. By this time you are already half way to a top end rebuild.....and associated cost
The short - it's fixed.
The long - so I drove cross-country along the A285, passing Goodwood on the way to Chichester. Then after a few hours parked in town, got stuck in traffic getting out, before escaping to the chalky-mud of the countryside, in the pouring rain.
I didn't have a chance to thrash the car, unfortunately, as the rev-limiter was with me, but the journey was brisk enough.
Cold, warm, and not-hot oil temps, the idle was perfect, dropping to around 900 in all scenarios, even in the Chichester-Jams.
Coincidently, my paid-for order of a CHT sensor was today cancelled/refunded, as they don't actually have any. I think I'll see how it goes rather than ripping out the original just yet...
The long - so I drove cross-country along the A285, passing Goodwood on the way to Chichester. Then after a few hours parked in town, got stuck in traffic getting out, before escaping to the chalky-mud of the countryside, in the pouring rain.
I didn't have a chance to thrash the car, unfortunately, as the rev-limiter was with me, but the journey was brisk enough.
Cold, warm, and not-hot oil temps, the idle was perfect, dropping to around 900 in all scenarios, even in the Chichester-Jams.
Coincidently, my paid-for order of a CHT sensor was today cancelled/refunded, as they don't actually have any. I think I'll see how it goes rather than ripping out the original just yet...
Just to update - at least 100 miles of mostly thrashing since the Varioram seal was replaced - this is a video, honest, not a still with fake audio added
Idle is indicated at something under 900 RPM.
Vimeo link - varioram idle - engine fully warm
Idle is indicated at something under 900 RPM.
Vimeo link - varioram idle - engine fully warm
For ref I believe the seal part no is 999 201 371 00 or SKF/INA size G8x12x3.
I only know this because there are two on pre-vario cars at either end of the resonance flap shaft and they’re not listed on any pre-vario parts diagram anywhere! According to the Porsche they don’t exist! This was the cause of a squeak on blipping the throttle on my car and a slightly rough idle.
They are however listed for vario cars hence the p/n above. Given their age all will likely be on their way out. See below for what a 65k mile one looks like vs new.
I only know this because there are two on pre-vario cars at either end of the resonance flap shaft and they’re not listed on any pre-vario parts diagram anywhere! According to the Porsche they don’t exist! This was the cause of a squeak on blipping the throttle on my car and a slightly rough idle.
They are however listed for vario cars hence the p/n above. Given their age all will likely be on their way out. See below for what a 65k mile one looks like vs new.
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