My m50 is pinging. Running out of ideas.

[Wishno87]

So about a month and a half ago (when is started warming up around here) my m50 started lightly pinging at times. At first it was hardly noticible but now it has become fairly pronounced.

It only does it once the car is warmed up and I mostly notice it on the highway when I try to accelerate.

Things I have tried:
New knock sensors. The original ones looked pretty shitty.
Cleaned maf (and icv while I was at it).
Smoke tested it and found a leak between the intake and the head around #6.
Installed all new intake gaskets and new intake air temperature sensor.

Still pings as much as ever. I always run premium fuel and I have had almost no problems with the motor for almost five years now. Lately I have noticed the GFs e34 m50 is doing the same shit to a lesser extent so I ordered the same parts for her car.

What gives?

[digger]

check and see if there are any deposits on the plugs and run some seafoam through it.

what air box are you using? if you have an open filter the higher IAT can increase likelihood

[Wishno87]

Ya I was thinking about trying seafoam next. I do have an open filter though. Should I try shrouding it off? Ironically I bought a podi vent gauge to monitor air intake temps but of course it doesn't work for shit.

[digger]

Ya I was thinking about trying seafoam next. I do have an open filter though. Should I try shrouding it off? Ironically I bought a podi vent gauge to monitor air intake temps but of course it doesn't work for shit.

yep i would enclose it, even insulating foam 12mm thick with the shiny silver coating. it to shape to seal off the cone and contorted in the engine bay does a good job as long as it is restrained

[justin_l_]

Ya I was thinking about trying seafoam next. I do have an open filter though. Should I try shrouding it off? Ironically I bought a podi vent gauge to monitor air intake temps but of course it doesn't work for shit.

Care to elaborate? Plan on installing a podi setup this weekend.
On topic, carbon deposits can cause pinging. Have you tried to run higher octane fuel (unleaded race fuel of some sort) to see if it goes away?

[Wishno87]

Care to elaborate? Plan on installing a podi setup this weekend.
On topic, carbon deposits can cause pinging. Have you tried to run higher octane fuel (unleaded race fuel of some sort) to see if it goes away?

I installed it a few months ago and nothing on it works. The wiring should be pretty simple but somehow everything either doesn't read or reads some crazy number. It may end up being an easy fix but I don't have the will to dig out all the wiring to look at it again.

Would the seafoam help with the carbon deposits? I could try some octane booster but that would just be a very temporary bandaid. It has never done this before so it would be a fixable issue.

[Ryann]

In for a definitive solution here. Having this exact issue. Know of a couple others also. I will add that mine seems to disappear at about 2900 rpm or so.

Edit: have you tried unplugging the intake air temp sensor?

[mpowerful]

The other thing that can cause pinging besides iat that are high is running excessively lean. Fuel cools the charge making it less likely to detonate up to a point. Try cleaning your injectors.

[Wishno87]

When I pulled my intake to change the knock sensors and intake gaskets the injectors looked brand new but I will run some injector cleaner though it.

Could the fpr have anything to do with it? Not enough fuel pressure?

[Wishno87]

In for a definitive solution here. Having this exact issue. Know of a couple others also. I will add that mine seems to disappear at about 2900 rpm or so.

Edit: have you tried unplugging the intake air temp sensor?

Downshifting does usually help when I'm on the highway. The intake air temp sensor is new but at this point I will try just about anything.

[Wishno87]

Spent the last two hours researching this on forums and I did not find one single thread where someone successfully remedies this issue except for one. Some guy replaced his vanos unit and it stopped pinging. Maybe the timing was too advanced?

Then again I see people with m60s and the same issue and they have no vanos.

[Ryann]

As far as I know and can think of it is ignition timing rather than cam timing that would cause preignition, so the VANOS thing doesn't add up for me. Adding to the mystery is that I can drive down the road and watch my a/f on the Modis and it's damn near perfect the whole time.

[Wishno87]

So if yours isint running lean then maybe carbon deposits? Do you get any cels?

[Ryann]

No CEL. Recently pulled the plugs and scoped the chambers, definitely some carbon in there. Scraped a piston top and it looked like a fairly thin layer.

[justin_l_]

What are you guys running for tunes? Maybe there is just too much timing for the motor? I remember my old orange car with a mark d chip would ping, that was a non vanos motor. Swapped chips and it was gone.