Can a mismatched set of plugs cause Knock Retard??
08-07-2003, 06:42 AM
#1
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Can a mismatched set of plugs cause Knock Retard?? I'm getting 2-3 degrees of KR, starting in at about 4500RPM in second gear at WOT. O2s are anywhere between 750-900 mV.
A friend of mine suggested that it could be a mismatched set of plugs. I've got TR55-IX Iridium plugs in all cylinders except 2 and 4...those I have Bosch +2 platinum plugs in (the ones I had cracked when the headers went in, so I replaced them with what I could get).
Could this be part of my problem? Is it worth swapping in a set of TR55 copper plugs to see if the problem is alleviated?
Thanks
A friend of mine suggested that it could be a mismatched set of plugs. I've got TR55-IX Iridium plugs in all cylinders except 2 and 4...those I have Bosch +2 platinum plugs in (the ones I had cracked when the headers went in, so I replaced them with what I could get).
Could this be part of my problem? Is it worth swapping in a set of TR55 copper plugs to see if the problem is alleviated?
Thanks
08-07-2003, 11:09 AM
#3
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Re: Can a mismatched set of plugs cause Knock Retard?? I don't see how it could. Now worn plugs can most certainly cause some pre-ignition (changin plugs often cures pinging.) But mismatched plugs, so long as they are in good shape, shouldn't do this...so far as I can imagine.
08-07-2003, 04:06 PM
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Re: Can a mismatched set of plugs cause Knock Retard?? Bosch is the magic word here. The first thing I would do is get rid of those worthless Bosch platinums. It's quite likely that the part number for those Bosch's cover three or more different heat ranges. For the LS1 it just might just be on the high side of that scale, possibly causing detonation and therefore knock retard.
