Datalog knock?
05-10-2017, 02:50 PM
#1
Datalog knock?
sorry if this is the wrong place to post but I pulled my first datalog today on my way home from school. it picked up ~255 knocks. I didn't hear it knock once (It has hollow cat and I think 2.25" pipes? with stock manifolds so it would be hard to hear) The car runs good, I've never heard it knock and i'm kind of worried as this is my only car right now. What do you guys think?
91 firebird 305 tbi
91 firebird 305 tbi
Last edited by Faolan; 05-10-2017 at 04:12 PM.
05-11-2017, 08:52 AM
#2
Moderator
iTrader: (1)
Join Date: Mar 2002
Location: Chasing Electrons
Posts: 18,401
Likes: 0
Received 215 Likes
on
201 Posts
Car: check
Engine: check
Transmission: check
Re: Datalog knock?
The 228 counts at start up is normal. This is due to the noise of the starter engaging the flywheel. Hard to say whether the remaining counts are from false knock or real knock. Can check the spark plugs for peppering on the center cone.
If present that means that at some point there is real knock.
Can also put a higher octane fuel in the tank and see if that reduces the frequency of knock counts.
Note that the TBI f-body ECMs also do a forced knock test. That is they will add a bunch of spark timing to force the engine to knock. After two attempts with no knock reported the ECM sets code 43.
RBob.
If present that means that at some point there is real knock.
Can also put a higher octane fuel in the tank and see if that reduces the frequency of knock counts.
Note that the TBI f-body ECMs also do a forced knock test. That is they will add a bunch of spark timing to force the engine to knock. After two attempts with no knock reported the ECM sets code 43.
RBob.