ecobb993

Any thoughts on the best additive to keep the dreaded carbon buildup at bay?

Ventil Sauber or Techron or ?

Greg D.

Techron is highly recommended on this board, that and frequent italian tuneups (as in "rev the crap out of the car")

Ron

I've been using Jectron and Ventil Sauber. I believe it is preferred by Steve Weiner.

STLPCA

I too have been using LubroMoly's Ventil Sauber (valve cleaner) & Jectron (injection system cleaner) on the advice of several mechanics. Techron v. VS, who knows which is best? However, the VS comes with a cute blue funnel

I do know my car runs noticeably better after a DE weekend.

Rick Lee

Have you guys seen the threads by some of the carbs, MFI and CIS folks on squirting water in there to break up the carbon? Seems to be a very effective cost-free panacea. I wonder how it would work on a 993.

Steve Weiner-Rennsport Systems

Rick:

Be VERY careful about introducing water into the induction system on these cars!

Ruining a Mass Air Sensor will not make your day and hydrolocking a cylinder will trash your checking account.

IMHO,....Its much cheaper, just as effective, and FAR less risky to use the various high-quality products for this specific purpose.

Someday I'll tell you about the people who used water to loosen & remove carbon that wound up with bent & burned valves. When water is used in this fashion, the carbon REALLY comes out,.....

Its not good at all.

Addendum,......Regular use of these products will really help keep valves & injectors clean and maintain sharp throttle response, but I do not think they will prevent the air injection passages in the heads from becoming clogged and triggering a fault code. I think minimizing cold idle time and driving off immediately after startup and running the engine to redline from time to time helps the most.

KeithR3

When is a good time to use these products. Before an oil change or after? Does it matter? How often?

STLPCA

Keith
Before an oil change is preferred since to the extent these products work their way down the cylinders, they may cause some contamination of the oil.

Ray Calvo

My vote is with Greg D.; 77K miles on a '95 and no problems using these techniques (when the car gets out of the garage, it DEFINITELY gets driven long enuf to fully heat up the oil)

ecobb993

Thanks for the responses, but:

Aparently the previous owner of my just purchased '96 with 77k miles didn't follow the above advise on additives and driving technique and my CE light has just lit with the excess carbon EM.

What additive/technique has been found successful in cleaning the pipes out sufficiently to at least get through the emissions test (short of pulling and scraping the heads)?

Edward

Aparently the previous owner of my just purchased '96 with 77k miles didn't follow the above advise on additives and driving technique and my CE light has just lit with the excess carbon EM.

Sorry to say, but I think you just joined "the clooged air passages team" (not to be confused with HWFM Racing). From what I recall form numerous previous threads (I have no first hand experience with this so go to the archives when it's up), there is NO quick, easy, or cheap fix for this. What you CAN do, however, is look for the thread that electronically bypasses (fools ?) the circuit so that you can be rid of the CE Light. If it's any consolation, at least the "problem" with the clogged air passages is not really a problem with drivability.

Edward

ecobb993

For what it's worth, I've had a stroke of luck (or genius) and have passed the test! Here's how:

* Reset the CE light.
* Added Techroline to the gas.
* Drove 20-30 minutes at 5k+/- revs.
* Next day (to allow to cool and to wait for my navigator to be available) we carefully ran through Porsche's readiness cycle (being careful to keep the revs below 3k) ending at the inspection station.
* After showing the guy how to open the fuel filler door and start the car he ran his series of tests and we passed!

I'll continue to run with good quality gas and Techroline to reduce the chances of having to go through this every year. (And hope this wasn't a one time stroke!)

Or, maybe I'll get a big bonus before then and have the valve job done.

tom_993

I like Jectron and Ventil Sauber as well, but I sometimes use other brands for variety. They all probably have some strengths and weaknesses. Switching now and then gets you the best of all of them.

Tom
'95 993

nman413

What regularity do you tend to use Techron or VS?

KeithR3

Where do you get Jectron?