bypass knock sensor?
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Q45tech
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- Car: 1990 Q45 342,400 miles 22 years ownership with original engine
1995 G20t 5 speed 334,000 miles 16" 2002 wheels - 205/50/16 Sr20ve vvl
Re: bypass knock sensor? (brette10)
Knock sensor [on 90-95Q] don't affect emission test as they really only work on high load accelerations and don't illuminate a check engine light.
If they are bad, the ecu does reduce the ignition advance a few degrees which I have never seen as a cause of emission failure.
Now 96 and later engines with OBD2 are more sensitive and will fail because the emission computer looks at diagnostic port and see the knock code.
Plugged/reduced flow egr will throw a knock code because the engine is knocking from lack of egr at cruise and tip in acceleration till the ecu enrichens the mixture for acceleration.
If they are bad, the ecu does reduce the ignition advance a few degrees which I have never seen as a cause of emission failure.
Now 96 and later engines with OBD2 are more sensitive and will fail because the emission computer looks at diagnostic port and see the knock code.
Plugged/reduced flow egr will throw a knock code because the engine is knocking from lack of egr at cruise and tip in acceleration till the ecu enrichens the mixture for acceleration.
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paranoidjack
- Posts: 1417
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- Car: 2012 Infiniti M56 S
2003 Infiniti M45
2001 Infiniti QX4
2000 Infiniti Q45
1998 Nissan Pathfinder
1996 Infiniti J30
Re: bypass knock sensor? (brette10)
Can I bypass the faulty knock sensor in my '96 j30 so that I don't have to deal with it??? Seems to be a somewhat vestigal part!
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Q45tech
- Moderator
- Posts: 14296
- Joined: Tue Apr 30, 2002 3:19 am
- Car: 1990 Q45 342,400 miles 22 years ownership with original engine
1995 G20t 5 speed 334,000 miles 16" 2002 wheels - 205/50/16 Sr20ve vvl
Re: bypass knock sensor? (paranoidjack)
Very important part or they wouldn't have wasted the money...........very important so that ecu can advance timing to achieve maximum mpg at cruise.
Knocking drives the rod and its bearing directly downward into crank greatly reducing the lives of bearings............severe knocking can crack the piston top and the spark plug insulator/tip.
Knocking drives the rod and its bearing directly downward into crank greatly reducing the lives of bearings............severe knocking can crack the piston top and the spark plug insulator/tip.
Re: bypass knock sensor? (brette10)
I know for my '94 Altima SE, the nominal value of the KS is about 550k ohms. When my KS went bad I put a ~550K ohms resistor in it's place and the the KS code never came back. I guess for the emissions test you could do that but I don't recommend leaving it in place.
I thought pre-96 cars weren't really tested for diagnostic codes since an emission test center would had to have a large inventory for the different pre-ODBII designs. So if the CEL isn't ON they wouldn't be able to check, or at least the cheesy emissions testing centers wouldn't be able.
I thought pre-96 cars weren't really tested for diagnostic codes since an emission test center would had to have a large inventory for the different pre-ODBII designs. So if the CEL isn't ON they wouldn't be able to check, or at least the cheesy emissions testing centers wouldn't be able.