3.2 pinging??

[dj393]

Before anyone slams me...I have used the search function, but didn't find much related to 3.2's
My 89 3.2 carrera has started pinging between 3,000 and 5,000rpm. Any ideas what might be causing it?? I know the timing is controlled automatically and I use 90 or higher octane gas. The car is completely stock (not chipped). When it is cold outside the car runs great with no pinging, but when weather gets above 65 degrees, car starts pinging. The temp of the engine is not getting to hot. I'm starting to run out of things to check. Car has 193,000 miles (not yet rebuilt, but probably needs a top end pretty soon)

Let me know if you have any ideas!

Thanks!

Don

[livi]

Interesting!

As I understand 'pinging' is the sound of detonation happening more or less spontaneously (when it shouldn´t). Higher octane being less prone to self detonate. If you use high enough octane level what could then cause aberrant detonations ? Stock engine as well. Also is pinging not more likely at very high revs, rather than medium ?

I am just thinking out loud as a complete tech ignorant - will be very educational to hear what the expert panel have to say.

[cgarr]

Bad fuel would be my first guess (ok slam me for guessing) but if nothing else has changed? Otherwise a carbon-ed up engine can detonate? Have you run any Techron thru the fuel system yet? Or you can change the rotary switch on the dme to reduce the timing and increase the fuel until you figure it out..

[KFC911]

Have you verified that you do indeed have a stock chip? I know other's have been surprised when opening the DME for the first time, not realizing that the PO had installed an aftermarket chip. LorenFB is indeed correct, a lot of them push the limit too far.

ps: Do you have 93 octane in your area? If so, does it make a difference?

[IROC]

Originally posted by cgarr
Otherwise a carbon-ed up engine can detonate?

If all other obvious things check out, this would be my guess. I had an old Toyota 4Runner that pinged and I checked the compression and was seeing about 190 psi in all cylinders (it had about 160k miles on it at the time and ran great otherwise). I think there was simply enough carbon in there to raise the compression ratio. Fixing this is the hard part. Since this was a Toyota, I ran water (!!) through the engine with it running and got the compression back down around 175-180 or so and it helped.

Just a data point.

[dj393]

Have not actually opened the DME to verify chip. I ran some techron through it about 6 months ago, and didn't seem to make a lot of difference. We don't have 93 octane gas here (that I can find) but I usually make sure I use no less than 90.

[jbrinkley]

change the fqs switch and see if things change. If they do then you can start all the hard work

[jbrinkley]

oops, here it is

[Wil Ferch]

By 89 the 3.2's required premium gas. The way the ratings were done...this would be 98 octane ( Euro) or the equivalent 93 octane ( US). US Rating basis is typically 5 points lower for the same gas.

Using 90 grad, US...is no surprise that you'd probably hear pinging..it's clearly sub-par as to octane requirements.

One of the 7 positions of the DME switch will indeed help for sub-par octane.

- Wil

[livi]

Wil,

Are the 89 models different in this aspect to the rest of the Carreras ? Or are we just talking US models ? I have driven my 85 on Euro 95 for two years and I even have a SW chip that Steve claimed had no problem with that octane number. I have never had any pinging.

[dfink]

Is it possible that with all those miles you have so much carbon built up on the heads and pistons that it has effectively raised the compression. You might take a look at some of the de-carbonizing threads.

[88911coupe]

dk393,
Just got back from Tulsa this am. Did this just start or has it been happening all along. I could get 91 Octane at that Phillips 66 at 96th and Delaware which seemed to work great, although I have an '88 which may be slightly different. I have run Seafoam through a vacuum hose hooked up to the back of my intake which seems to help. There's a thread on how to do it but basically you run some through, shut it off for a few minutes and start it back up. It will smoke like there's no tomorrow so don't do it without ventilation.
Adjusting the settings may solve the pinging but it's not getting to the bottom of the cause.
Do you meet up with John, Bill, Gary, Dan, et al at Wild Fork for breakfast? I don't know if they still go there Saturday mornings but it's a great group of Porsche people and some stunning Porsches show up, along with that occasional Gallardo or Ferrari.
Later

[Wil Ferch]

Markus:

For USA...84 and 85 models were rated for (US) 87 Octane....Euro equivalent to 91 or 92 octane....

By 1989, the remapping to get more HP for US models required the Carrera to use premium US fuel ( US octane 93....Euro Octane 98).

The Euro market cars...unless cat optioned for a tax break...used ( I think) Premium fuel all along...AFAIK...as the Euro cars had 10.3 compression ratio and US cars had 9.3 or 9.5.

- Wil

[dfink]

One other thought. You might make sure that the throttle position switch is working above 3/4 throttle.

[ischmitz]

Someone mentioned that bad worn spark plugs also can cause pinging. And this seemed true for my 3.6. My plugs had 15k miles and the car started to ping under WOT and low RPM's when really warm. With the new plugs this has gotten noticable better.

Just another data point.
Ingo

[livi]

Originally posted by Wil Ferch
Markus:

For USA...84 and 85 models were rated for (US) 87 Octane....Euro equivalent to 91 or 92 octane....

By 1989, the remapping to get more HP for US models required the Carrera to use premium US fuel ( US octane 93....Euro Octane 98).

The Euro market cars...unless cat optioned for a tax break...used ( I think) Premium fuel all along...AFAIK...as the Euro cars had 10.3 compression ratio and US cars had 9.3 or 9.5.

- Wil

OK, thanks Wil!