Idle control valve improperly installed?

[PHUTNGUYEN92]

Hi all,

I'm relatively new to the Pelican community and need assistance/expertise help in diagnosing a potential problem. Recently bought an '88 with 100,000 miles in late February (photo attached).

PO own it for 8 yrs but didn't drive it much. Used Chevron Techron with last gas fill up as recommended by my mechanic. Started noticing blue smoke at start up but goes away after engine warms up. Also Idles around 1600 rpm at stop lights but can force to lower to 880 rpm if down shift into 2nd gear. To make long story short I noticed the ICV was installed upside down (pic attached).

Initial start up with cold engine, rpm is around 1300 rpm and drops down to 880 shortly. Druck press at idle is 3. Is that high? Could ICV affecting sticky idle and high druck press? Anything else it could affect. Love my '88 and want to make sure she's performing as she should be. New to Porsche w little mechanical skills but mechanically inclined.

Thanks for your help in advance.

[brighton911]

When cold, the oil is thicker and yes, the oil pressure will be on the high side. Yours is normal. Expect to have about 1 bar pressure once the oil is up to temperature. It is also not uncommon to have some smoke on start up. It is your overall oil consumption that matters. Anything more than one liter/quart per 1000 is starting to get high.

[PHUTNGUYEN92]

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[PHUTNGUYEN92]

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Brighton911,

Druck press @ 3 after 1 hr drive. Shouldn't it drop down after an drive.

[E Sully]

It seems high, but other interesting part is your oil temperature gauge is reading cold for a 1 hr drive.
Blue smoke on a Carrera is unfortunately common. The valve guides wear quickly and allow oil to pass.
Your picture of the ICV not shown. Idle when your car is warm should be 880 rpm. Have you checked if the Idle Position switch and the Full Throttle Switch are set correctly?
Another issue on a high mileage car is air leaks. This can cause idle problems.

[mo-mon]

Beautiful car!

It should drop to around 1-1.5. Is that your temperature after a one hour drive?

Possibly your oil pressure sender is on its last legs.

Tell us more on what has been done since you bought it. Did you replace fluids? Did your mechanic give it a post purchase inspection?

You say you're mechanically inclined. Buy a Bentley manual & start getting to know your "baby". We're here to help.

[PHUTNGUYEN92]

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Picture of ICV.

E Sully,
Picture 2 hours. I noticed during longer drive druck press showing 3. Temp just below half point. Haven't found any vacuum leak yet.

Mo-mon,

Thank you! My 1st Porsche, loving it! Druck press maybe bad because after after 1 hr drive it bounces between 3-3.5. Had mechanic do ppi, oil change after purchase. Car had extensive clutch and repair done in late 2017.
Car drives wonderful. Just curious of ICV.

[mo-mon]

When my oil "druck" pressure started bouncing or gave erratic readings, I changed my oil pressure sender and this fixed it. It is a bit challenging to change it because of the aircon compressor but doable. Good thread on replacement- https://forums.pelicanparts.com/porsche-911-technical-forum/502982-another-oil-pressure-sender-replacement-thread-pics.html

ICV doesn't affect oil pressure but a higher idle will have higher pressure but not 3bar like yours after a long drive.

[FrankM_]

Are you sure the ICV is on the right way ? On mine, the arrow for the 'flow' is visible to the front, and the labels are on the back !

[FrankM_]

Sorry, due to import scaling of the image, the arrow has become invisible.
Here is the zoom

[PHUTNGUYEN92]

Thanks for all the advises so far.
I think I have 2 potential problems.

1. Bad oil pressure sender. Currently fluttering like a butterfly between 3 - 3.5 @ idle after 1 hour drive.

2. The ICV is definitely installed upside ( arrow in the back facing up). Strangest thing is she's idling at 880 rpm! I tried installing it with arrow down, she idled very rough around 400 - 500 rpm. I re installed with arrow pointing up and she idles perfectly at 880. I I went ahead and bought a good used ICV, installed it, same problem.

Questions for you guys.

1. Is it possible to adjust idle even if ICV is installed upside down to make car idle @ 880 rpm

2. Even though she idles at 880 with ICV installed arrow pointing up, does this affect engine performance at all?

3. Should I install ICV with an arrow pointing down and try to adjust idle.
If so, how do I do that.? For many of you this is very basic but new to me. Willing to learn with your help.

Thanks in advance for your help!

[HaroldMHedge]

Before adjusting the idle, I would clean the ICV and install it correctly. Afterwards see if you really need to adjust the idle.

Here's a good thread on removing and cleaning the ICV: What a difference - 3.2 ICV cleaning!. This thread has a link to a video on fixing a bad cold idle. At 8:45 into the video it discusses ICV removal and testing.

[PHUTNGUYEN92]

Originally Posted by HaroldMHedge

Before adjusting the idle, I would clean the ICV and install it correctly. Afterwards see if you really need to adjust the idle.

Here's a good thread on removing and cleaning the ICV: What a difference - 3.2 ICV cleaning!. This thread has a link to a video on fixing a bad cold idle. At 8:45 into the video it discusses ICV removal and testing.

HaroldMHedge,

Clean and tested the ICV and installed it w arrow pointing down. Car idled very rough. Re-installed w arrow pointing up she idled @880. Weird!

[HaroldMHedge]

That is weird.

Did the ICV appear to have any internal wear that could cause to be sticking?

Try adjusting the idle with the ICV arrow pointing down. Others from the Pelican brain trust may have a better answer.

[PHUTNGUYEN92]

I even bought a good used ICV, installed properly but with same result. I'm thinking previous owner installed incorrectly and adjusted the idle to 880. Is that even possible with ICV installed upside down?

To me the car runs great, but again I'm new to Porsche. No leaks what so ever. Could it run better w ICV installed properly w idle proprly adjusted.

Previous to my purchase the extensive repairs were done.

Clutch & flywheel
Slave & master
Valves adjustment
Cap & rotor
Plugs & wires
Fuel filter
DME Relay

Any addition help would be appreciated.

[stlrj]

My 87 ICV was also installed backwards and it took me years before I figured it out. It made all the difference with my idle after I flipped it around.

Joe
87 Carrera

[PHUTNGUYEN92]

I flipped the ICV around, I jumped the 2 connections on the service port and adjusted the idle to 880 RPM. Now my 88 is idling around 650, too low! I'm thinking the idle position switch is bad because it failed the continuity test. Am I correct in assuming this.

Thanks for your help in advance.

[old man neri]

Why is your temp so low after an hour? The only I have seen my temp that low after an hour was when it was -20F.

What does the inside of your oil cap look like? Is it covered in frothy oil?

[PHUTNGUYEN92]

Originally Posted by old man neri

Why is your temp so low after an hour? The only I have seen my temp that low after an hour was when it was -20F.

What does the inside of your oil cap look like? Is it covered in frothy oil?

Old man neri,
I live in WI. It was cold out that day and picture was taken 2 hrs after drive. Oil cap looks normal. Temp normally registered below mid point so far during spring drive.

My main concern now is the low idle, does the idle position switch control that? I am not getting any continuity reading w meter.

[ischmitz]

Just to make sure - the ICV is vibrating when the engine isn't running and doing the little jerk-motion about once per second, right? That is just to confirm it is controlled properly by the DME and there is no issue with the DME.

Next, if your idle switch on the throttle body isn't engaging during idle (binding of linkage, adjustment, etc.) or has an electric issue where the DME doesn't see it closed when you let off the accelerator your engine will never idle properly. The idle switch contact tells the DME it is time to control the RPM with the ICV and the advance. It changes modes internally.

Without the idle switch seen closed the DME will set the ICV position to a pre-defined value around low RPM but will NOT control idle speed actively. As a result idle can be anywhere close to the target but it will hunt around and behave erratic.

Cheers,
Ingo