m60 engine pinging

[ejhiggins]

Hi guys i'm new to this site and i have two questions regarding the ECU on my 95 540i production date 9/94. The first issue is that the engine is pinging with or without a performance chip installed, premium gas and octane booster in the tank, i took the car to an independant shop and they hooked it up to their computer wich detected the engine pinging but the ECU would not do anything to adjust the timming, they told me that the timming was fine and so were the knock sensors, they said that if the knock sensors were bad they would trigger a fault code, so the only thing they suggested was to replace the ECU , do you think that is the problem? And the second issue that i think may be related to the first one is when i turn the engine on first thing in the morning or whenever the engine is cold as soon as the engine fires i hear a loud high pitched metallic BINGNNN kind of the same sound a bell makes, and it only makes it for a second. What do you think that could be? Thanks a lot for the info

[winfred]

i would do a new set of ngk plugs (BKR6EK) and look for any vacuum leaks, if the fuel filter has over 10k miles id replace it, after checking it over and replacing any parts unplug the computer for a few minutes to let it reset, then see where you stand on the ping, it will take a day or two for the computer to totally adapt to the condition of the motor, another possible thing screwing with it, the pcv valve on the back of the intake manifold can blow and really make it run weird, the intake manifold gaskets can leak during cold running and mess with it too, the gaskets can seal up as the motor warms up and be hard to track down

[winfred]

the ringing sound most likely the starter solonoid is getting slow in retracting and the gear is getting wacked by the flywheel, and the flywheel is making the ringing sound

[ejhiggins]

i just checked the plugs this past weekend and they look fine, my main concern is that while the car was hooked up to the diagnostic computer at the repair shop it detected the engine pinging but the computer wouldn't adjust at all to correct the problem

[ejhiggins]

how do i correct that?

[ejhiggins]

why does it only make that ringing noise when the engine is cold?

[winfred]

id need to hook my own scanner to it to really say, it's not allways right up there in bold print on the scanner what the problem is, it's more knowing how to use the info given to draw your own conclusion, best guess on my part assuming that there is a check engine light condition, the computer is in a "limp mode" due to some problem or bad sensor of somekind and the computer is running from the preset safe injection map, a knock sensor reading out of range will throw a code (the m60 has 4 sensors under the intake)

[winfred]

cold luberacant in the starter?! tighter tolerences in the starter when cold?!

why does it only make that ringing noise when the engine is cold?

[ejhiggins]

i haven't had the engine light on so i doubt there is any bad sensors, im going to repalce the fuel filters since i have never repalced them, some of the plugs had little white dots on them so i'm probably running a little lean. Thanks a lot for your info, let me know how to check the PCV valve and any other vacum leaks i thoght about the intake manifold gasket but the engine only pings when it reaches normal operating temperature.

[632 Regal]

for about an hour, then start the car without touching the throttle for at least 5 minutes, then go give it hell.

Bet that fixes it.