Cadride

Hey guys looking for anyone with experience with false knock issues. I have a 94 5.7 TBI with 2.3 Whipple, 195 AFR heads, roller cam, hydraulic lifters, EBL. More specs https://www.thirdgen.org/forums/album.php?albumid=8107. This is a new setup so I do can not compare to the past.

I started with Delphi AS10015 knock sensor and 16128261 ESC and have since switched out the knock sensor for 10456126.

From what I can tell:

• AS10015 was for 93-96 5.7 C1500 TBI flat tappet cam
• GM 16128261 ESC was for 92-95 5.7 C1500 TBI flat tappet cam
• AC Delco 10456126 New knock sensor was for 95-94 5.7 Corvette, Camaro, Firebird, roller cam

I am currently running plugs NKG BKR6E-N 11 and 93 octane. I had the truck on the dyno and could not hear detonation in the engine when the ECM was going in to RA. While on the dyno we pulled a lot of SA out of the engine under boost to try and get rid of the knock, but had no success. There is no sign of detonation on the plugs after 1000 miles and several hours on the dyno.

I would like to know if there is anything that I should try before throwing KS and KM at it trying to eliminate false knock. I have thought about running higher octane gas to see if goes away, but with all my experimenting I don' t think it will go away.
I have uploaded a log file showing the knock. In the first tab I included a few seconds before and after RA and I highlighted the RA cells in red. In the second tab I just have the instances of RA.

RBob

iTrader: (1)

Sure looks like false knock also to me. Make sure that the knock sensor isn't any tighter then 11 ft/lbs. If that is OK may need to mount the sensor on a 45* street elbow. That will desensitize it a bit.

RBob.

Cadride

When I changed the knock sensor out I made sure to use plenty of teflon tape and I used a short ratchet and tried to only tighten it to snug.

Do you think a brass fitting would desensitize it to much compared to a steel fitting?

Thanks for your input.

RBob

iTrader: (1)

I don't know if a brass fitting would or not.

RBob.

Cadride

I got the fitting installed and it did help, but did not solve the problem completely. One thing that I did notice is that my SA shoot up to 88 - 89 while under boost. The max SA is set to 32. The only thing that was changed between bins is VE table and I took 1% out of the fuel table under boost to help lean it out a little.

I installed a 45 degree brass street elbow (FNPT 1/4" x MNPT 1/4") with teflon on the fitting and KS and this time I used a torque wrench to install the KS to 10 ft*lbs.

I attached the log that I ran showing with RA highlighted in red.

RBob

iTrader: (1)

This is a reporting issue with the EBL Flash firmware. The real SA is going negative relative to the DRP, which is also what is correctly occurring at the crank. We have a new version of the ECM firmware (V 2.3), but haven't put up a notice about it on our web site yet.

You can email me and I'll send the update to you.

Need to track down the false knock. It could be a number of things, loose bracket, broken bracket, rattle in the exhaust, bad bearing in an accessory, and so on.

RBob.

Cadride

Thanks Rob, as we spoke in email. Had a few contributors to false knock.
Aftermarket Cats were junk and the core was loose in side of the can
Couple small header leaks between the head and the header
Reduced the boost from 12 psi to 5 psi
Wrong Knock module the BHL made the biggest gain of removing false knock

I added SA back under boost and it is stronger than it has ever been. The other day when I really got on it I noticed some knock, but for the most part I am not showing any knock. I need to make sure that it I do not have any knock showing up before I increase boost to 8-10 psi. Looking for TBI Whipple pulleys?

Z28/ZR1

You might want to consider methanol injection. You can put one together or buy a kit. It serves as a safety net, plus you can actually make more power as it will cool the charge.