Mc.Queen 964

Hi guys.

I think that i've got a new problem, now, my car (with hot oil), goes to 1.100 RPM (at idle, in stead of 900 RPM), and it sounds more like "pro pro pro" (Like a Harley Davidson) in stead of "propropropro", and too, it does more backfires. (it has tip gearbox)

Could it be a rotor or distributor caps? which are the symptoms of a distributor belt broken?


Regards!

Brentflyfish

interesting - I look forward to seeing the responses. I have a C2 manual and my RPMs cycle up and down between 500 and 1100.

Mc.Queen 964

Too I hear a strange noise like " shhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh" I don't know what happens...

RSGulp

Sounds like an intake air leak. Take a look at this thread for a possible solution.

https://rennlist.com/forums/964-foru...l-no-luck.html

Mc.Queen 964

I was wrong, the shhhh was the A/C belt.

It goes perfect up to idle, but in idle has problems. I cleaned the idle regulator.. I think that could be O2 sensor?

ian89C4

Possibly, my idle was erratic, and then the car would just die at traffic lights. It would start right back up, but it could not maintain idle. I had the shop hook it up to the computer and it said a bad O2 sensor, replaced it and no problem.
It is worth a try, and if it hasn't been replaced yet on the car it won't hurt to replace it anyways.

Cheers

tbennett017

I would still check for vacuum leaks, and if you're not sure about your distributor belt, it's really worth checking, as a broken one can really cause some problems. Though I would agree with Ian on an O2 sensor...

Mc.Queen 964

today I checked my belt and it's ok, and no vacuum leaks.. sure..

It have to be 02 sensor..

Gerald Myres

Check that the throttle micro switch closes at idle. It will make an audible click when it closes. Idle will be irregular if the switch does not close.

Mc.Queen 964

I checked my idle switch, it does "click" when it closes.. so... 02 Sensor 100%?

When I start it sometimes do a backfire.. I think that only can be the 02 sensor, because my idle switch is OK, y cleaned the idle regulator.. and my distributor belt is fine.. so.¿could be a rotor or a cap distributor? I think no but I have yo ask..

Regards!

darth

Based on the information you've provided, I'd be searching further for a vacume leak as the backfire and the shhhh sound (i.e. although somewhat subjective and difficult to put a sound into words) are tell tale signs.

springer3

Troubleshooting is cheap and quick. Replacing the wrong parts is expensive and time-consuming.

Read the disgnostic codes. They will tell you in plain English if it is the O2 censor, one of the Hall sensors, the CHT or other sensor. The code reader lets you check each injector, actuator, and switch.

If that does not get to root cause, some basic troubleshooting is in order. Are you sure there is not a vacuum leak? Symptoms are consistent with that. Check fuel pressure and fuel flow, and while you are at it, check for water in the fuel. Check the compression. Check the spark timing. If you are still not at the solution, an ignition scope will pinpoint ignition and fuel problems cylinder-by-cylinder.

Good luck. I love this site because it does identify the common problems and lets you avoid the pitfalls that make ownership less fun and more expensive

Mc.Queen 964

"shhh" sound was from the A/C Belt, no for a vacum leak, and last year in Porsche center they change all vacums tubes.

I don't know if buy a new O2 sensor or go to my Porsche dealer to connect piwis..

darth

In addition to the vacume lines have you checked the 6 rubber intake tubes between the intake plenum and the intake ports? Check that the clamps are tight and there are no cracks in the rubber? Is it a backfire or a missfire? In other words does it "bang" when you let off on the throttle or when you're applying throttle and the engine rpm is increasing? Or is it "banging" when idling?

Mc.Queen 964

Banging when idling... I checked these 6 rubber rubes, and they are new.