Twood

Some background
My '91 964 engine has a the following modifications:

• cat bypass
• primary exhaust bypass
• Promax performance chip
• Lightened fly wheel
• RS Alternator pulley
• 80K miles or 128K kilometers

The problem
At takeoff the engine is dying on me. If I depress the clutch I am able to rev the engine and once that happens it is fine. There is no misfire at high revs, the problem only appears when taking off from idle. I feel the car is running rich and there is some smoke at idle. The problem does not happen all the time but is becoming more frequent. It is more noticable when the car is cold first up in the morning, though "cold" is relative-here it has been 18-22 degress C (about 65-70 degrees F) at 5.30am.
It almost feels like the engine is flooding but once the revs rise it seems fine. The car idles fine, it is only at takeoff that the problem arises and I believe it has been getting worst in the last month.
I have been a run 2 courses of fuel injector cleaning additive in the fuel for the last 3 weeks but with no real result.
The car is regulary serviced with a new fuel filter about 8K ago.

Suggestions so far have been
Fuel Injectors need cleaning?
Cylinder head temperature sensor requires replacing?
Oxygen sensor?

All suggestions and help appreciated.
Thanks in advance Ken

garrett376

do you know the last time the o2 sensor was replaced? That would be my bet. Injector issues occur through all RPM. O2 sensors don't last a long time so give that a try if you have no way to monitor it (hammer).

Twood

The O2 sensor was replaced about 18months ago or approximately 25-30K kilometers ago. It was bought from Ebay and was not a Bosch O2 sensor.
I have the ScanTool Diagnostic interface that plugs into a laptop and reads the O2 sensor but I do not know what these reading should be.

Twood

I have ordered a new O2 sensor but I am still very open to suggestions if anyone can come up with alternative ideas.

Indycam

"Cylinder head temperature sensor "
Have you looked at it ?
Tested it ?

Twood

It was suggested early on that it could be a cylinder head temperature sensor. I have the a scantool diagnostic tool that hooks into a PC. I believe this give cylinder head temperatures but I do not know what that reading should be.
Can anyone help with what the reading should be?
I dont mind buying one if that is my problem.

Indycam

https://rennlist.com/forums/showthre...ad+temp+sender

Twood

Thanks Indycam
I will check it tomorrow and let everyone know the results.
The help is very much appreciated.

Indycam

It might be just a wild goose chase , but you never know till you test .
The cylinder head temp sender went nuts on my air cooled vanagon , if I held the wire one way the motor ran fine and if I pushed the wire over it would kill the motor . $10 vw part vs a $100 porsche part ? Whats that about ?

Is it nice and warm in Brisbane ?

Twood

Warm humid sultry-thats the weather not me.
Any idea of the part number for the the VW temp sensor? The Porsche temp sensor is ex Germany. Porsche price is AUD $330 and they wonder why we buy so many parts from the US.

Indycam

http://busdepot2.webappcabaret.net/d...ber=0280130012

It would be funny if the part was the same same , vw vs porsche .

330 Australian Dollar = 283.523 US Dollar

Indycam

http://www.automotion.com/productpag...&cid=10&sid=84

94.95 US Dollar = 110.546 Australian Dollar

Twood

Indycam
Thank you for this information. I have asked for a shipping quote from Automotion and will order the temperature sensor as soon as it comes through.
Have a great Christmas and New Year and hopefully Santa will deliver a brand new GT3 RS into your Christmas stocking in thanks for your help. Regards Ken

Indycam

Did you test the old one ?
Please don't replace it just for grins .

"a brand new GT3 RS "
No thanks , a stock 964 goes fast nuff for me .
Now if you have santas ear , a 356 would be ever so nice .

springer3

Check compression before ordering any parts. Check fuel pressure. Check fuel flow. Is the fuel clean? New parts are a waste if there is a simple problem. BTDT.