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The knock sensors are designed to only detect a narrow range of frequencies (corresponding to the resonance of your engine block, as a function of bore diameter etc). This frequency is typically several kilohertz, so the vibration you were experiencing would be far too low a frequency (< engine redline ~6600rpm = 110hz) to be detected by the system.

Thanks charlay86...had a completely different take on what I thought they did...need more research!!...Cheers Shayne

The ecm doesn't get any sort of signal to say that a coil or spark plug isn't firing it just sends with no feedback
faulty injectors are the same .
I would imagine though someone with knowledge in tuning would pick up on the mixture being out on the 02 sensor .

That would explain it...thanks again Dec_head..I tested the other two coils like you mentioned and clueless here didn't watch the end of the lead..my eyes are still glowing LOL.....they work just fine!!....point taken with the knock sensors...I thought they worked on vibration much like a spin dryer...if it rattles..it stops or in the case of a car reduce power dramatically to get home safely...had no idea that they operated on frequency while located in the water jacket...I didn't associate the word "knock" with high frequency sound...cheers Shayne

also to add to the knock sensor info .... they are more of an instantanious thing, so when it detects a certain amount of knock it retards the timing, it will then eventually return to normal timing over a few seconds provided there is no more knock ....

In the early to mid eighties, I worked on datsun 1200, 1600, 120Y and the folks Stanza...I could do pretty much everything myself (under my dads guidance) including clutch plates, brakes, carburetor, distributor, condensor etc etc....never saw a mechanic unless I really made a hash of it...it was a lot easier adjusting springs and weights in a carbie to get things moving...emissions control and ADRs weren't even a consideration...now I am making the transition from what I remember of carbies, venturies, timing lights and accelerator pumps to the modern EFI....sensors and computers taking out a lot of guess work..I am still learning the basics of EFI....the more I know about what the system does, how it does it and why, the more sense it starts to make....just an incredibly complex way of running an engine compared to the carbies....yeah I know...emissions....I like carbies!!!....anyway, plenty of work to do...cheers...

Hello Holden202..didn't know you were on....OK so they reset in a way provided the engine settles...

im always on

you are correct, and there are settings that you can adjust to determine how quickly the knock retard is delayed etc also how much knock it has to sense before it will start pulling timing out.

haha..of course you are..and thanks for the info..both on this thread and the police memcal...you make a good point..relating what EFI does to that of a carbie does make things simpler and I am still going over the basics, comparing the carbie to the various sensors, tables etc...can be frustrating on occasions but I am getting there...info on the knock sensors, injectors, CAS and so on is very helpful and the picture is coming together...

its a very big picture!