Timing ...help!! 94 k1500, 5.7, $OD, 7427

[BigBanks78]

Keep pulling timing down in that area to see if it stops. My dad thinks his roller rocker arms my be to noisey, he is having same issue, vortec v6, 427 ECM. He tried corvette knock sensors but ECM didn't like them.
I am by no means an expert tho!!!

[sturgillbd]

How did you eliminate the egr valve? I ask this because if you just turned off the error code, the PCM is still going to use the egr routine. Make sure you maxed out the Temperature for EGR On scalar. I also maxed out the Minimum Speed for EGR scalar.

Brian

[dispoejoe95]

How did you eliminate the egr valve? I ask this because if you just turned off the error code, the PCM is still going to use the egr routine. Make sure you maxed out the Temperature for EGR On scalar. I also maxed out the Minimum Speed for EGR scalar.

Brian

Pretty sure I made those changes to the egr but I will double check my file when I get home.

[BigBanks78]

My dad was reading about a corvette with stock roller rocker arms had to make some knock sensors that were less sensitive so they wouldn't pick up rocker arm noise.

Notsaying thats your problem just that if you pull timing and you still have same knock go over mechanicals!!

i keep having software problems that turn out to be mechanical :-)

[dispoejoe95]

Big....It is certainly worth looking into.

Btw, Brian, I double checked and I have already made those changes for eliminating the EGR. I thought I had...I'm sure I read to do it on a thread somewhere in this forum.

Thanks for the suggestions guys.

[sturgillbd]

I would make sure the exhaust isn't rattling or rubbing against the frame etc. I would also make sure I wasn't running lean. If vehicle is in PE mode, you really need a wideband to know what your afr actually is.

[dud]

I have pretty much the same setup and the only difference with my problem was that I could actually hear
pinging.I turned off "Altitude Spark Bias" and the problem went away. Couldn't hurt to try. I found the answer
In this thread;
http://www.gearhead-efi.com/Fuel-Inj...=altitude+bias

[dispoejoe95]

Keep pulling timing down in that area to see if it stops. My dad thinks his roller rocker arms my be to noisey, he is having same issue, vortec v6, 427 ECM. He tried corvette knock sensors but ECM didn't like them.
I am by no means an expert tho!!!

I had thought about double checking the adjustment on my rockers but Is a knock sensor that sensitive that it will retard the timing because of rocker arms or lifters being a little noisy?