[dstrother]

Hey guys, I'm new to the water cooled family. I've been an air cooled 911 guy. I bought my 911 SC in 99 and love her. About a year ago I picked up a 92 968 tip, cab as a more daily driver. I love this car, catch myself all the time still just looking at her. Now for the help I need. She idles very rough when started cold. Like shakes the front end a bit (headlight vibrates). idle is about 950, pulled the plugs looking for a miss, they look great. I notice there is no cold idle, just a steady 950 no matter the temp. If I give her just a lil gas, up to 1050-1100, the idle smooths out. It also smoothes out once the car reaches operating temp. I read on an old post in a different forum that this will be the DME temp sensor. Sounds logical to me. Any input?

Second problem is the hot/cold flap in the HVAC system doesn't work. I have to reach under the dash and manually adjust where the control rod clips to the motor to adjust the temp. Is there a common problem that causes this issue that I should check first?

Thanks in advance for the help,

Dave

Partial Post: Please Login or Register to read the full post.

[Waylander]

HI

 

the DME temp sensor is just under the top hose and has a blue top or should do, this controls the temp data fed to the ECU for water, some times its the plug and pins all corroded up, I had to replace both the sensor and the plug on the loom before mine started behaving

 

like this

http://www.ebay.co.uk/itm/New-Genuine-FA...SwGzxZgt50

 

the flap not moving is a broken clip, very common issue

 

two bits are normally needed

944 572 314 00 Plastic Bit

 

944 572 217 00 Clip

Partial Post: Please Login or Register to read the full post.

[dstrother]

Thanks, Did your car exhibit the same symptoms with the DME sensor?

Partial Post: Please Login or Register to read the full post.

[ds968]

I hope you have better luck with finding what's causing your cold start issues than I have .. I changed the temp sensor, all ICV components, the O2 sensor, the DME relay , the fuel check valve and fuel filter, checked for vacuum leaks, etc , etc , etc .. and the car still shakes, stumbles and stalls unless you let it warm up at idle for ( at least ) a loooong five + minutes before driving it . Once fully warmed up it runs fine, as if nothing was ever wrong . But I noticed you indicated this happens no matter what the temperature is outside, so you might just have a sticky ICV ..? Mine happens mostly if the outside temps are cold , so I thought it had something to do with the temp sensor ( the one mentioned here with the blue cap ) , but that wasn't it.. I'm still speculating your issue is ICV related .

Partial Post: Please Login or Register to read the full post.

[tejon007]

I also wish you well with troubleshooting this problem...I had a similar issue with one of my cars & could not get it figured out for a while (also replaced the ICV, smoke test for leaks, etc.). 

 

Finally figured out it was a vacuum leak after all, but a real hard one to find (cracked vacuum hose that looked perfect until you bent it & it had even passed two smoke tests)...

Partial Post: Please Login or Register to read the full post.

[ds968]

Tejon007 - do you remember which specific vacuum hose that was / located where ? Maybe it's a hose which develops cracks easier than others because of the way it's bent or closer to heat or whatnot ..in which case it may be something we should all check carefully even though it doesn't necessary shows a crack or detected via smoke tests ..

Partial Post: Please Login or Register to read the full post.

[tejon007]

DS, 

 

If you have an '88 Pontiac Fiero GT...it might be helpful to you, otherwise no (it was one of the two vacuum hoses on the left side of the engine bay going to/from the charcoal canister & was particularly difficult to tell it was cracked)

 

My point was meant to say, that if you have a rough idle - - troubleshooting it can/should include looking for vacuum leaks and sometimes a vacuum hose can pass smoke tests, visual inspections...but, still be the problem. 

 

Check/maintain the usual stuff & if it still idles rough, another inspection of the vacuum hoses where you carefully bend each one to see if it's cracked may get you to the answer.   

Partial Post: Please Login or Register to read the full post.

[ds968]

DS, 

 

If you have an '88 Pontiac Fiero GT...it might be helpful to you, otherwise no (it was one of the two vacuum hoses on the left side of the engine bay going to/from the charcoal canister & was particularly difficult to tell it was cracked)

 

My point was meant to say, that if you have a rough idle - - troubleshooting it can/should include looking for vacuum leaks and sometimes a vacuum hose can pass smoke tests, visual inspections...but, still be the problem. 

 

Check/maintain the usual stuff & if it still idles rough, another inspection of the vacuum hoses where you carefully bend each one to see if it's cracked may get you to the answer.

Oh crap, lol, I completely overlooked the " one of my other cars " part of that sentence ... But still very good advice even if based on a non-968 experience ....

Partial Post: Please Login or Register to read the full post.