Throttle adjust - Now pinging?

[Capt. Carrera]

Anyone else encounter this?


THE PROBLEM:
I checked the throttle on my 911, and it was only opening about 75-80%. So I adjusted it. Now I have pinging at about 3,200 to 3,500 RPM under medium load. It does not ping under light, or WOT, loads.

ACTIONS TO DATE:
I removed the Weltmeister chip the PO installed, and reinstalled the OEM chip. That helped some, but it still pings a bit. (I can feel the pinging through the pedal, as well as hear it.)

OTHER POSSIBILITIES:
Could the PO have somehow advanced the timing? I thought the Motronic handled all the timing. This is a stock motored 1988 3.2 Carrera running on 93 octane gas.

MY POSITION SO FAR:
Until I hear otherwise, I'm rationalizing it's because I'm applying more throttle than I'm used to. But it seems odd a stock '88 car would ping.

SOLICTING YOUR INPUT:
Thoughts?

[afterburn 549]

KISS method, 1 st. check you timing,. and operation of the dizzy

[Capt. Carrera]

I hooked the brown wire back up. This is the wire leading to the Motronic to reduce the timing some. I'll see how it does tomorrow....

[Por_sha911]

The factory chip does not require 93 octane. If you are getting audible pinging with 93, you have a problem because these cars can hide the pinging unless it is very pronounced. Check your timing first. You may also want to pull the plugs and see if they are showing signs of running too lean.

[Capt. Carrera]

I do believe I found the culprit....

I got to thinking about this problem, and decided I was not being logical. I finally decided the problem was symptomatic of a small vacuum leak. Went out to the garage and started feeling around behind the throttle body. Sure enough, one of the two small hoses that go to the base of the TB was off. Must have pulled it loose when I took the elbow off between the AFM and TB so I cold see the butterfly. Kids and wife are asleep, so I'll have to wait until tomorrow evening to verify that fixes it.