Knocking when I floor it but goes away.....

[Ed Valvo]

Weird. I heard what I think is audible knock when I nail the throttle and the boost kicks in. Then it goes away once I get moving. The SM shows nothing except for 1-3 degrees on the shifts. Anyone else notice this or have experienced this? Boost is only set for 14-15 PSI. Chip is new 50# Extender with 23/21 timing. It's also on CA crap gas. 91 octane.... It also may be time to change out the old fuel filter.... But why knock only when I floor it?

 

[ledzeppac]

I dont know about your knock issue exactly but I think 21* timing is too high with 15 lbs and 91 octane. I would turn down the boost...

 

[TurboDave]

That is a good bit too much timing for the gas you have out there in CA!! The amount you're hearing and the amount that's showing on the scantool can be two completely different things, depending on the sensitivity of your knock sensor.

 

[GNBeswick]

That happens to me to, I get knock in the beginning....and I know its real knock because I can hear it, but it goes away if I stay on it. Damn our california gas and its crapiness.....

 

[MaxVO2]

Put some Xylene in the tank, get alcohol injection, or lower the timing in that chip. Or, lower boost of course..

If you can hear the knock, you can rest assured your motor is feeling it much worse, even though your Scanmaster only shows 1-3 degrees retard. I'm not sure if you have the fast update patch in your chip, or if there are tuning issues with your car like vacuum leaks, etc.. so it's best to just fix your minor problem now before it becomes a major problem later.

Billy
Montgomery Village, MD

 

[Ed Valvo]

Thanks for the replys guys. I guess I should know better. Car has been sitting for so long that I forget. The car used to get a steady diet of 100 unleaded and the boost was rarely under 20 PSI. If I recall, 15 PSI was a bit much for 92 octane in my car. It makes me wonder though if 91 is actually 91...... Car runs perfect otherwise. I just wanted to daily drive it a bit and enjoy thae car. I guess I'll lower it to 12 PSI and see what happens. But if I do that, I might as well slap the stock turbo on it.

 

[SPOOLFOOL2]

FWIW, Most tuners put in about 18* of timming for our 91 octane, oxygenated, wonder-gas .

 

[Razor]

Your chip probably has knock ignore built in..that means it ignores knock when you initially stab it.

The extender will also do that on the downshift.

Bet thats your problem.. give it some octane bet your issues go away.

 

[Mackinblack007]

Ed go get some 100 for her, and then look from there for your problem, I go to the 76 off vasco in livermore for the good stuff.

 

[marleyskater420]

Originally posted by Mackinblack007
Ed go get some 100 for her, and then look from there for your problem, I go to the 76 off vasco in livermore for the good stuff.

You could also go to Vishnu. 6.00$ for 100 unleaded, and 7.50 for C16.

How much is that 76?

Vishnu is in Pleasonton, which saves you gas from driving to livermore.

 

[KillrV6]

hey ed, my car has allways had a similar sound. my scanmaster only pickes up 2-3*s , near shifts, but some times i can hear it Ping for a sec or two...

maby scanmaster is missing somthing in its low data streem rate.

 

[KillrV6]

i run 16*s low rpm and 17 up top i belive on 91, and it runs pretty good. not much knock except in certain weather situations (it got extreemly cold recently.)

-Evan

missing the NCTB meetings because of school

 

[Ed Valvo]

It went away after lowering the boost. I guess I do need more octane.

Vishnu? Is that a shop?