Has anyone else seen fluctuations like this before at high rpm?:



We thought it might be the K&N dropin I have, so I switched to an open cone filter with no change in issue.

Does this look like high rpm BOV flutter?

BTW, in the graph MAF= maf grams/sec

 

I started having MAF/load fluctuations when my MAF was on its way out... mainly due to the over-oiled filter that came with my Cobb intake.

 

Just so you can compare, this is what it looked like when I had a bad MAF:



You could be seeing the onset of the same symptoms, it's hard to tell. I do know they are very finicky because after cleaning my air filter and very lightly oiling it, then swapping in a new MAF, it still would muck up after several hundred miles and start giving me crap readings.

But honestly, I think what you're seeing is normal. Mine is a definite example of a "bad" MAF.

 

That does seem more extreme then mine. Do you still have this issue?

 

Yes. It ended up looking something like your graph even with a new MAF and a lighter-oiled filter. I continuously cleaned the MAF with electrical contact cleaner to get it back to behaving normally. Eventually, it ended up looking just like my previous datalogs again.

 

Thanks for responding.

I will have to try to swap my maf with a buddies and see what happens. The car feels normal. Even though the fluctuations in load are clearly there you cannot feel them.

 

I cleaned the MAf with some high quality electronics cleaning spray. This however, did not resolve the issue.


Run1


Run 2


Run 3

 

Oh, definitely not the MAF spiking.

Though, your load does seem really low for your modifications. Have you logged MAF voltage?

 

Yep...hit 4.85 at redline.

 

Is your load graph scaled really funny? Cause 240-ish load is a little low for that kind of airflow and boost. I'm thinking more like it spikes to 285 or so and tapers to 265. That would make more sense.

But otherwise, I think everything looks good on your end. I would worry if you start to get IDC spikes. That's the indicator or something being horribly wrong.

 

Load peaks about 280-290 and tapers to 240-250.

I do get IDC fluctuations consistent with the fluctuations I am seeing in load. The car drives fine and accelerates smoothly, there is no feeling that something weird is happening. The only reason I even started a thread on this is because i also get some slight knock in this area that is proving difficult to resolve. I believe the fluctuations may be causing the knock.

 

It looks like it stays pretty in-line with the boost... Personally I wouldn't be too worried.

 

It's just kinda weird. I haven't seen this in anyone else's logs....

While I don't consider myself a perfectionist, I like things to be in-line with the expected norm.

 

Is your ignition timing advance bouncing around due to the load fluctuations? This can induce knock possibly.

 

Nope, timing is stable.

I really can't find a root cause.