civic HX goes lean 17.1 at 60 mph
05-14-2008, 07:47 PM
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civic HX goes lean 17.1 at 60 mph
I recently had wideband put on and boost gauge put on. it usually stays at 14.9 unless of course I go wot. But even with a load on the motor at around 60 the AF reads 17.1 and wont go back to normal unless I stomp the gas. but my engine light isn't coming on. Also I should mention I have a B&M FPR and a walbro fuel pump. Should I be worried or is this normal with the d16y5 lean burn?
05-14-2008, 09:49 PM
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Re: civic HX goes lean 17.1 at 60 mph (AJWatUC)
Assuming you're running an HX engine...
That's what they're supposed to do - run lean when you don't need 'power', e.g. cruising along at 60 or whatever.
HXs have a roller cam (ye$ roller cam) and laboratory grade O2 sensors.
What it does, when the motor is loafing, is shut off half the intake valves and lean the mixture WAY past stoichiometric!
It gets away with this by cutting off half the intakes - which causes the uber lean fuel mixture to swirl in the combustion cambers - and its closely monitored by super sensitive O2 sensors.
Anyway, enjoy the gas savings and don't worry about it...
That's what they're supposed to do - run lean when you don't need 'power', e.g. cruising along at 60 or whatever.
HXs have a roller cam (ye$ roller cam) and laboratory grade O2 sensors.
What it does, when the motor is loafing, is shut off half the intake valves and lean the mixture WAY past stoichiometric!
It gets away with this by cutting off half the intakes - which causes the uber lean fuel mixture to swirl in the combustion cambers - and its closely monitored by super sensitive O2 sensors.
Anyway, enjoy the gas savings and don't worry about it...
05-15-2008, 01:48 PM
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Re: civic HX goes lean 17.1 at 60 mph (BlackDeuceCoupe)
I thought it was fine because I knew it has roller rockers and is supposed to burn lean But I didn't know it closed the valves halfway. Thanks for the reply
05-15-2008, 10:36 PM
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Re: civic HX goes lean 17.1 at 60 mph (AJWatUC)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by AJWatUC »</TD></TR><TR><TD CLASS="quote">...I didn't know it closed the valves halfway.</TD></TR></TABLE>
Okay, let me clarify that...
It doesn't close the "valves halfway"!
You have 8 intake valves. What it does is disable 4 of those intake valves.
And, those 4 valves don't close totally - they stay open 'a hair' to keep gas from puddling around the disabled intake valve pockets - let's say 99.9% closed.
In the old days, Honda did the same thing - firing an uber lean mixture - through the use of a pre-combustion chamber, e.g. the CVCC head.
MORE INFO HERE
The HX head, however, is an infinity better solution!
Okay, let me clarify that...
It doesn't close the "valves halfway"!
You have 8 intake valves. What it does is disable 4 of those intake valves.
And, those 4 valves don't close totally - they stay open 'a hair' to keep gas from puddling around the disabled intake valve pockets - let's say 99.9% closed.
In the old days, Honda did the same thing - firing an uber lean mixture - through the use of a pre-combustion chamber, e.g. the CVCC head.
MORE INFO HERE
The HX head, however, is an infinity better solution!
Hx's are suppose to run like that
06-15-2008, 01:47 AM
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Re: civic HX goes lean 17.1 at 60 mph (Panda Eg6)
Lol, you mean you have 16 valves and it disables 4 of them, leaving you in 12 valve mode. 
Anyways when coming from below something like 2500rpm or 3000rpm is where it goes from 12 valve mode into 16 valve mode. As an FYI, there isn't quite a specific RPM which is argued aggressively around here but more like a range since it may enable 16 valve operation at 3000rpm but disable it at 2000rpm. yada yada yada. Anyhow thats what designates it as a vtec-e engine, because it runs in 12 valve operation with 2 exhaust valves, 1 fully open intake valve (not VTEC deep) and 1 slightly open intake valve, open just enough for fuel to not pool up behind it.
Anyways when coming from below something like 2500rpm or 3000rpm is where it goes from 12 valve mode into 16 valve mode. As an FYI, there isn't quite a specific RPM which is argued aggressively around here but more like a range since it may enable 16 valve operation at 3000rpm but disable it at 2000rpm. yada yada yada. Anyhow thats what designates it as a vtec-e engine, because it runs in 12 valve operation with 2 exhaust valves, 1 fully open intake valve (not VTEC deep) and 1 slightly open intake valve, open just enough for fuel to not pool up behind it.
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