Burnt plastic smell

[andes]

I've notice a burning smell occasionally, it seems to come in through the ventilation system when I push the car a little. Is smells like burnt plastic, and seems to occur after the engine has been running at high revs. Has anyone had a similar experience? Any hints...?

Thanks a lot,

David

[HenryV]

Clutch?

[andes]

Hmm, that's a thought, but would the clutch burn even if I am not using it much? The other day it started smelling as I was going down hill in second gear, around 3-4K RPM, not really on the gas, and not shifting...

[HenryV]

The smell usually is delayed from the actual moment that caused it.

Couple of things to consider:

- Did you use the clutch before coming down the hill (maybe a stop sign)?

- And do you push the clutch pedal all the way to the floor when shifting?

- And how do you release the clutch? - what is the typical RPM upon release?

- Do you accelerate (push gas pedal) prior to fully releasing clutch pedal?

You may have a tight clutch cable, so the clutch doesn't quite, or maybe just barely, disengage.

Alternative is that you have a habit of 'slipping' the clutch, i.e. coming up a little, maybe halfway, and keeping the clutch pedal in that position while pushing the gas pedal and accelerating, until beyond 1,500 to 2,000 rpm, causing it to heat rapidly.

I recommend to get the car rolling (with little gas), and release the clutch fully prior to pushing the accelerator. You can get the car rolling at around 700 - 1,000 rpm, and always make sure you clutch pedal is fully released prior to 'slamming' the gas pedal. Same applies to higher gears.

[andes]

Thanks Henry. I don't think it's clutch slippage, I am very careful with the clutch, and this has just started happening after two years of ownership. I still can't figure it our, it happened again yesterday after pushing the car on the freeway... :(

[1999Porsche911]

Carefully check that none of the electrical wire are touching the exhaust. O2 sensor wires in particular.

[andes]

Hmm, it does smell like burnt plastic, I will check out the wiring, thanks for that suggestion. THe weird thing is that the smell comes in through the ventilation system...