Assuming you have excluded the usual suspects, I though this fix might help some of you GTS owners.
I've elininated my pinging / pinking by switching the EPROM in my EZK to a GT one (slightly less agressive map at high revs / load with 2 degree less advance according to John Speake). I don't pretend to understand the whys and wherefores but if some GTS's are prone to pink despite full 6 degree protective retard from knock sensors (the default even if knock and Hall sensors are faulty) - and the EZK tests OK (don't necessarily trust the Hammer on this one) - then swapping to a slightly less agressive map makes sense.
And it has worked for me. No pinking at all now, despite still having suspect Hall and knock sensors which I am looking in to. And performance seems identical (depsite 2 degree difference at peak = ? 5 - 10 bhp) - if anything it feels more eager but that's probably psychological!
Total cost from John Speake - around £60 for the EZK diagnositic, and fitting the new GT EPROM. Great price and great service.
I am a happy man!
Could Porsche have made the mapping in the GTS EPROM a little too marginal ??
Hope this helps

Mark

 

Good deal Dr. Mark...nice to have a relatively cheap fix for your issue.....

so a somewhat related question....has anyone checked the CR on a GTS motor?...spec says 10.4:1....is there a - factor from the factory (in terms of -0.6 like the S4's)?

Also...maybe your CR is even more than 10.4 to 1 given excess deposits on the piston and in the combustion chamber due to the oil that the GTS typically consume (forged pistons/no oil drainback holes)???

How hard do you drive the GTS?..perhaps some seafoam..or venil sauber next fill?...

Later,
Tom
89GT

 

what kind of fuel are you using?

 

98 RON Shell Optimax

 

Interesting. So a GTS has a more aggressive timing advance than a GT. I wonder if that would help those of us who are at a high altitude (5300') with our power loss, which is about 16%. Since you need less octane at altitude the old tuners trick was to advance timing to help offset the power loss, they usually tried to advance 3 -5 degrees. Anyone have a set of GTS chips available?

 

I have found that mine was pinging when I had to load lower octane fuel due to shortage of higher octane at the pump recently. Having switch back to higher now I don't think I have pinging. I'm out of country right now and be back by the end of the month I will check it again at that time. If I have the problem I'll go for John's solution as well.

 

Novice question: could I do the same thing (advance) with Porken's gauges? It's cheaper, but maybe not as good to adjust cams as that applies over the entire rpm range? Chips are probably easier to deal with, but not always available. Isn't one notch on the belt 3 degrees?

 

A GTS EPROM only costs $40 - 50 - why bother adjusting the cams?

 

PorKens tool also changes when valves open and close, not just spark

 

Changing the cam timing will NOT change the igntion timing.....the igntion timing is from the flywheel speed sensor, no the camshaft (much more accurate.

I can suppy GT EPROMs to order, or EZK EPROMS with custom mapping.

 

...and I thought this was a thread about another pink 928, and how we can make ours match.

 

As I said, novice. I'm starting to understand the pieces.

 

Nicole, I can't even look at that. Someone burn this car and shoot the owner!

 

Won't change the ignition timing as John said. The valve timing may be advanced on one or both sides, and make it more likely to ping.

One cam gear tooth is 7.5 degrees or 15 degrees crank (ignition) advance or retard.

 

Sorry SteveG - on re-reading my mail sounded a little agressive.....