Octane # and pinging

[moo snutz]

Hey All - Haven't posted in a while, got a question.

 

I've got 2200 miles on my truck and I'm noticing a little bit of pinging, not too bad - I only hear it when I put my foot in it (it was more noticiable with the drop in K&N too). My question is: Should I try running a little higher octane? I'm running 87 right now. What benefits/drawbacks are there to running on 91 or 93? Besides cost. Does higher octane fuel give better performance in the winter?

 

Thanks

[bigdogs]

Actually higher octane gas is lower performance, it controls the pinging by dampening the explosion. That said if you are pinging you may need it so you get the explosion happening in the cylinder at the right time instead of too early. Your timing could be a little advanced too

[gunslinger45]

Bigdogs got it right. Higher octane gas burns slower to control detonation. I doubt your timing would be off on a new truck that has computer controled timing and knock sensors. I have heard many stories of intake kits leading to slight knocking, but conceptually, the computer should correct the air-fuel mixture to avoid any lean conditions that could lead to detonation leading to knocking. All this being said, if you are indeed experiencing knocking, than go ahead and try the next higher octane rating. I can think of no real drawbacks except maybe an extra 10 cents a gallon. You won't notice much of a performance difference uping the octane. The benefits of avoiding enging knock far outweigh any slight effect of bumping up the octane. If you continue to have any knocking as you increase octane then I would say you should take it to the dealer. If your new engine knocks with 91 octane, with or without the K&N, I would say something may be amiss.

 

Gunslinger

[Butch 02 Denali]

I agree with all the octane comments. But first I'd try cleaning the MAFS (Mass Air Flow Sensor) It will cure stock pinging problems about 50% of the time. The K&N is the culprit, though it will sometimes help even with the stock air filter. The problem is fine dust sticking to the sensor wires in the MAFS, causing false readings. Remove the MAFS and spray it from both sides with a non residue and plastics safe electrical contact cleaner. I got it at the local auto parts store, or you could get it at Radio Shack. Let dry and reassemble. Worth a try.

 

Butch 02 Sierra Denali

[moo snutz]

Excellent! Exactly the kind of info I was looking for. Is cleaning the MAFS a big job? I would hate to bung it up & find myself in a s**t puddle. Would a gun cleaning patch or something similar work for cleaning the wires?

 

Thanks

[Butch 02 Denali]

Excellent! Exactly the kind of info I was looking for. Is cleaning the MAFS a big job? I would hate to bung it up & find myself in a s**t puddle. Would a gun cleaning patch or something similar work for cleaning the wires?

 

Thanks

No,no,no,no,no! DON"T TOUCH THOSE WIRES WITH ANYTHING! Sorry to yell, but I had to make this point very strongly. They are very fragile. The cleaner is safe and easy. Get the right stuff, spray from both sides , let dry and reinstall. Easy job, the most difficult part is getting the sensor separated from the rubber sleeve it's in.

 

Butch 02 Sierra Denali

[Shaners]

I run a K&N drop in filter also.... The way I understand it, the oil residue from the filter can migrate up and out onto the MAFS. It's a simple cleaning job to just spray it with the cleaner and let it dry...

 

There is a little clip holding the wire harness into it, so pay attention to release the clip before you yank the wires out...

[JimWilson]

It's far more difficult to wrestle the intake tube off then it is to remove the sensor. Disassembly, cleaning and reassembly should be about a 20 minute job. It's rather simple, actually.

 

But heed Butch's warning about the wires; they are indeed fragile, and if they break you're fuc..., um, in a lot of trouble.

[moo snutz]

HOLY CRACK !! And here I was ready to wipe the wires down with a rag! Thanks for settin me straight - I'll pick up some sray & steer clear of touching the wires.

 

Later

 

Moo