Knock issues with LS-VTEC
02-03-2006, 08:10 AM
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Knock issues with LS-VTEC
i posted this tech as well, but seeing I think more ppl in here may have had this issue.
I have just put together an LS-VTEC with gsr head and p72.
I was really excited to have an knock sensor to aid in my tuning, but it seems to be giving me nothing but problems
When datalogging via crome pro I get alot of knock to the point i can feel the ecu pull tremendous amounts of timing. in the -10-10.50 range. Therefore I go pull a degree or two and the same thing happens. I pulled up to 10 degrees under boost and the same thing happens again. I started with .75 deg per pound of boost, which I feel to be conservative. But this seems to happen more frequently as soon as it hits vtec, knock goes into the red.
Now my knock sensor is on the front of the block where a powersteering bolt would go if i had power steering. and about 2-3 threads stick out beyond the block. and the wire is not shielded. Also one valve ticks a little.
Could i be picking up residual noise or could i have a bad sensor?
Sorry for the long story
Last night and today, I went out and just ran a conservative timing map with the knock sensor off and the thing hauls. i also checked the plugs last night and all looks good, no signs of detenation or anything.
Thanks in adavce for the help
Burke
i do have my egt wire zip tied to my knock sensor wire, i know all the egt does is change resistance, but could that be my problem?
I have just put together an LS-VTEC with gsr head and p72.
I was really excited to have an knock sensor to aid in my tuning, but it seems to be giving me nothing but problems
When datalogging via crome pro I get alot of knock to the point i can feel the ecu pull tremendous amounts of timing. in the -10-10.50 range. Therefore I go pull a degree or two and the same thing happens. I pulled up to 10 degrees under boost and the same thing happens again. I started with .75 deg per pound of boost, which I feel to be conservative. But this seems to happen more frequently as soon as it hits vtec, knock goes into the red.
Now my knock sensor is on the front of the block where a powersteering bolt would go if i had power steering. and about 2-3 threads stick out beyond the block. and the wire is not shielded. Also one valve ticks a little.
Could i be picking up residual noise or could i have a bad sensor?
Sorry for the long story
Last night and today, I went out and just ran a conservative timing map with the knock sensor off and the thing hauls. i also checked the plugs last night and all looks good, no signs of detenation or anything.
Thanks in adavce for the help
Burke
i do have my egt wire zip tied to my knock sensor wire, i know all the egt does is change resistance, but could that be my problem?
02-03-2006, 12:10 PM
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Re: Knock issues with LS-VTEC (bdavis)
Honda knock sensors do not require shielded cables. The output is high level, low impedance.
The fact that the sensor is sticking out a couple of threads is not a problem.
Remember, you are asking a knock sensor hear knock that you CAN'T hear, and at the same time, ignore noise that you CAN hear.
Piston slap from loose fitting forged pistons is the biggest cause of poor performance with knock sensors.
The fact that the sensor is sticking out a couple of threads is not a problem.
Remember, you are asking a knock sensor hear knock that you CAN'T hear, and at the same time, ignore noise that you CAN hear.
Piston slap from loose fitting forged pistons is the biggest cause of poor performance with knock sensors.
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