worf928

Please do not vote in the poll if your vote is about anything other than a GTS. (If there is enough interest I can make a poll about model-year / type-specific pining.)

Folks, I have this feeling that GTSs seem to have and/or develop pinging problems more-so that other 928s. I recall several threads wherein GTS owners have reported pinging. These are two recent threads about Drmark's GTS:

https://rennlist.com/forums/928-forum/271859-my-gts-pings-what-do-i-look-at-now.html
https://rennlist.com/forums/928-forum/272998-hall-and-knock-sensors-common-connector.html

Pinging, knock, pre-detonation sounds like marbles rolling around in a tin can. It can be hard to hear and sound like the can is off in the distance. It usually seems to happen during the first second or two of acceleration.

If you have had pinging in your GTS and cured it, please give us a quick summary of the fix.

bigs

I've never had this problem in my GTS.

However, my situation is a little different. Quite soon after I bought my car, I had Ketchmi install a RRFPR and 30# injectors with an eye toward S/Cing the car. I haven't as yet gotten around to installing a SC. The car was dyno-tuned for the bigger injectors and runs just fine naturally aspirated.

So maybe my experience does not reflect the norm...?

drnick

i have a 1992 engine, an 89 harness and GT eprom code for the ezk, GTS code for the LH but non standard cams. the loud exhaust might obscure any detonation but i dont think there is any having driven in cars where its been present im sure i would have noticed.

Drmark

Worf,
Good idea - particularly the what fixed it bit!
Mark

mspiegle

I thought it was pretty much accepted that GTSs ping a little? I had a very short conversation with someone who really knows their stuff and they mentioned that a GTS will ping just a tab when you get on it. Especially on 91. If you look at the fuel door, 93 is what you should be using.

The supermodel'd GTS pings when the intercooler isn't hooked up, but otherwise its fine. I modified the coding chip to run 91 octane. As long as the intercooler water is full, no pinging.

928ntslow

I am all about listening to EVERYTHING my car does from the time I turn the key to the time I turn it the other way. I am happy to say I have no pinging. I suspect it may be a timing issue with some of these cars. I may offend a few folks here, but is this issue happening with guys who just drive their car and don't know much about it and maintain it at a minimum? Flogged cars and poorly maintained/worn parts tend to promote these problems. All it takes is one weak link. I hope someone figures this all out.

Jim R.

Dave,

If all the electronics are good, injectors are good and oil use is in spec, is it possible the cams are a little advanced either from the factory or PO?

A trial of retarding the cams one degree (even two) may help to lose the ping. I have Porken's cam timing tool if you want to give it a try without removing cam covers. You are welcome to them to try it out if you want. Easy to note original setting then retard or advance as desired. Return to "stock" if no change.

I would also wonder if you guys are running lean with the factory fuel maps for emissions. Maybe a A/F guage could shed some light on that. A bump of 5 psi in fuel pressure with an adjustable FPR may be a good bandaid, or a session with the Sharktuner.

Just a thought, and since I would like to add a GTS to the garage one of these days I am interested in how to lose the chronic ping. If I can run a GT with 8+ psi without any pinging, I would hope a stock GTS could run without pinging as well.

Jim

Alan

New MAF helped reduce the occurrence - car is driven almost daily - but is very well maintained! - 91 octane fuel certainly does not help - I think this is the biggest reason, better fuel is rarely available here. I plan to try an octane increaser and see what effect that has.. anyone tried this?

Mike what is the coding for 91 octane (...Austraila?).

A cam timing change could maybe help - buts its set correctly to stock, compresssion is good - within 4%, new fuel regulators etc & both knock sensors work correctly - nothing is wrong with the car - just occasionally knocks under heavy load (just back off a bit...). I wouldn't say it is chronic now but it was clearly worse before the MAF change...

Alan

worf928

Vely Intwesting.

14 reports so far with 50% reporting pinging problems.

I'm going to post an S4/GT poll to gather comparative data.

EDIT: Jaysus.... I cannot even spel pol korectly. And u guys just lemme run around and don't say nothin...

Spelling corrected - hopefully. It's poll. I'm a moron sometimes.

bigs

Hey! I'm a Mormon too!!!

worf928

Not only can I knot spell. I suck at teh math too. I counted the Maybe as a Pinger rather than removing that data point. So, the score is 6 of 13 and 46.15% are Pingers.

Schocki

Gent,
My GTS pings exactly how it was described in other polls too. Only when you step on it at low RPM's.

The car drives overall great with very good gas mileage (22.5 MPG on highway). It only pings when the engine is fully warmed up. Some facts: LH-ECU new from John Speake. MAF new from John. What I find very interesting that the car pings with premium or midgrade in the tank. BTW the gas mileage is the same with midgrade.
Should I try an octane booster? The car is my daily driver with no problems overall...

cobalt

Hasn't pinged as of yet.

I did note that the PO had an invoice for an occurrence of pinging, as documented on the paperwork. The Porsche shop replaced the anti-knock sensor as a remedy. I have no other details to what truly transpired. I do know I have not heard the car ping once. Although I did have a valve tap once on cold start up. I turned the engine off and on again and it went away.

Schocki

Quick update
Filled my GTS up this morning with 19 Gallons of Premium (93 Octane) and added Lucasoil Octane booster. The results are the same! Drove the car to work nothing (cool morning)!
Late afternoon (temp 82 F) took the highway home with the AC on and there it was again ...pinging. Not as noticeable but still there.

Everything under the intake is new after I powdercoated it. I will hook up the spanner to see if it recognizes any detonation tomorrow...

Sterling why do you think that the intank pump could be faulty? Or better why did it cure the pinging on other 928's?

928ntslow

I have been thinking about this thread and wondering what on earth could be so different between these engines that half will perform well and the other half, well, less than well.

I have an idea of what is causing this and have narrowed it down to TWO things. This of course is based on that fact that all wiring and vacuum lines are in fine condition, injectors are not clogged and all sensors are functioning properly.

They are:
1) Engine temperature-cooling system
2) Spark plug type

Just for ****s and giggles, let's list what we are using for spark plugs and what coolant/temperature are we running. Also note if your car pngs.

1)COOLING
MIXTURE= Prestone 40% Distilled water 60%
NORMAL TEMP RANGE= 185-190 d F
2) SPARK PLUG
Bosch copper single electrode
NO PING