1pcarnut

shamrock, have you taken out your MAF sensor and cleaned it? That would be my next step after the ISV. After that the temp sensor sounds like a possible culprit.

shamrock

Actually no I haven't cleaned the MAF sensor , and must admit I've not heard of the MAF being cleaned before .. I'll have a look around on line for a diy .. Ta.
Btw I HAVE cleaned the ISV a few times.

polaris 993 sport

Yes I had this problem many years ago-engine temp sensor as I recall!
Never happened since! Perhaps 8 years going.

1pcarnut

You'll need to remove the air filter housing. The MAF attaches to the housing via a 1/2 twist so first remove the electrical connection to the MAF and the hose clamp on the intake side. Then you can rotate the MAF about 1/2 a turn counter-clockwise (if I recall correctly) to loosen it from the air filter housing. At this point the air filter housing should lift out followed by the MAF. Clean with MAF spray cleaner but do not touch anything inside it. All told should be around a 30-40 minute job. Holler if you have questions.

shadow993

I'm happy again....the porsche gods did not help much. First a bad sensor, then the new sensor was bad.

I put a new one in today in less than 30m and bam... My baby is back and running right.
The secret to getting it done quick is to remove the heat tube and cut into a socket. The cut allows you to run the wire through the socket for easy install. Without using the socket, I spent a total of 2 hours trying to get it to take by hand.

Slow Guy

Actually you only need to rotate the inner air filter housing about 20 deg. to get it to separate from the MAF, then unscrew the (large) hose type clamp holding the other end of the MAF sensor. And most definitely, use MAF Cleaner only, no carb or brake cleaner on the MAF! Over here CRC makes MAF cleaner but I'm sure Worth and many others make it on your side of the pond.

Edit: Sorry, I think you may be interpreting this post as saying the A/F housing does not need to be removed. No, the housing DOES need to be removed for access to the MAF. My intention was to say you only need to rotate the MAF/ AF housing connection apx. 20 deg to separate them, not the 1/2 turn as previously stated. Sorry for the confusion.

shamrock

Hmmm!
As per usual , this bloody forum just makes my to do list bigger than ever!

I reckon I'll need to change out the CHT sensor alright , I'll leave that to my mech , but I can't resist cleaning the MAF anyway

Only thing is , some of the instructions above are confusing my poor lil brain!

Am I correct in saying I DON'T need to remove the airbox?

Is there an on line 'how to' with pics!!?
I did a search but there doesn't seem to be any on p.car or on the forum here...

axl911

From the symptoms you described, you have a vacuum leak.

Don't replace the CHT yet. You can easily test it. Locate the white connector on the connector tree on the left side of the engine. Measure its resistance value and compare it to the chart. If you are not getting infinity resistance or zero resistance, chances are it is still good. Record the resistance and air temperature, and post it here.

I've seen the CHT, and replacing it is 10000% times the effort comparing to locating the cht connector and putting a voltmeter on it.

axl911

Yeah, I know the next question you're going to ask...here it is.

Slow Guy

To answer your question, you NEED to remove the airbox to get to the MAF, it's between the airbox and the intake. Sorry, I don't seem to have a photo of the MAF as it sits in the engine, maybe someone else does.

You do NOT remove the airbox to get to the CHT sensor. The connector for the CHT is on the other side of the engine compartment and the CHT itself is on the front left side of the engine accessed from below the car.

That answer your question?

First photo is of the CHT connector in the engine bay, left side of the engine behind the blower (blower removed). In the photo several of the connectors are unplugged, this is while I was dropping the engine.

Second photo is where the CHT actually is, behind the rubber "plug". Again accessed from under the car.

shamrock

Thanks guys for that fantastic info , pics and charts .. I'll get working!

shadow993

Shamrock.... To get the cht in and out takes zero mechanical ability ....more about patience.

Depending on what a dealer charges...it could cost around $500 vs a $125 diy. The dealer now wants $225 for the part and said a couple of hours for labor.

I can send you the socket I modified for install. Go to an auto zone or if you have a obdii reader...it should tell you if it is the cht. Atleast my $80 version did.