VTEC-E lean burn mixture
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Honda-Tech Member
Joined: Apr 2019
Posts: 335
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From: Pakistan
VTEC-E lean burn mixture
Hi
I have read a lot about VTEC-E on internet but couldn't find one thing. If my car is idling or it is running below 3000 rpm and green econ light is off, in which mode I am in 12 valve mode or 16 valve mode???
Because the green econ light only lits on specific speed and rpm, so 12 valve mode should only activate at that point for lean burn???
Or the whole time engine is running on 12 Valve???
I have read a lot about VTEC-E on internet but couldn't find one thing. If my car is idling or it is running below 3000 rpm and green econ light is off, in which mode I am in 12 valve mode or 16 valve mode???
Because the green econ light only lits on specific speed and rpm, so 12 valve mode should only activate at that point for lean burn???
Or the whole time engine is running on 12 Valve???
Honda-Tech Member
Joined: Sep 2018
Posts: 204
Likes: 20
From: Idaho
Re: VTEC-E lean burn mixture
Hi. The green light is not an "econ" light, it's a shift light. I believe it runs off of manifold pressure (which is determined by speed and rpm).
The VTEC-E is based on engine speed only. If your car is running below 2500 rpm, it is using 12 valves - above 2500 rpm, 16 valves.
Lean burn is determined by the ecu and there is no indication of it. It is definitely not related to VTEC or the shift light. It doesn't happen with the throttle closed (idling). It occurs when you are driving with the throttle only slightly open and with sufficient manifold vacuum. I had a trip computer that would display instantaneous fuel mileage, so I could tell when the car was in lean burn. Lean burn is detectable. When cruising you will notice the engine lose a little power (maybe even stumble) and you have to give it a little more throttle to keep it going, that is when it's going into lean burn. In 4th or 5th gear, at a steady 45 mph or less, it is always in lean burn getting over 60 mpg.
The VTEC-E is based on engine speed only. If your car is running below 2500 rpm, it is using 12 valves - above 2500 rpm, 16 valves.
Lean burn is determined by the ecu and there is no indication of it. It is definitely not related to VTEC or the shift light. It doesn't happen with the throttle closed (idling). It occurs when you are driving with the throttle only slightly open and with sufficient manifold vacuum. I had a trip computer that would display instantaneous fuel mileage, so I could tell when the car was in lean burn. Lean burn is detectable. When cruising you will notice the engine lose a little power (maybe even stumble) and you have to give it a little more throttle to keep it going, that is when it's going into lean burn. In 4th or 5th gear, at a steady 45 mph or less, it is always in lean burn getting over 60 mpg.
Honda-Tech Member
Joined: Nov 2003
Posts: 1,900
Likes: 104
From: Plano, Texas, USA
Re: VTEC-E lean burn mixture
Hi. The green light is not an "econ" light, it's a shift light. I believe it runs off of manifold pressure (which is determined by speed and rpm).
The VTEC-E is based on engine speed only. If your car is running below 2500 rpm, it is using 12 valves - above 2500 rpm, 16 valves.
Lean burn is determined by the ecu and there is no indication of it. It is definitely not related to VTEC or the shift light. It doesn't happen with the throttle closed (idling). It occurs when you are driving with the throttle only slightly open and with sufficient manifold vacuum. I had a trip computer that would display instantaneous fuel mileage, so I could tell when the car was in lean burn. Lean burn is detectable. When cruising you will notice the engine lose a little power (maybe even stumble) and you have to give it a little more throttle to keep it going, that is when it's going into lean burn. In 4th or 5th gear, at a steady 45 mph or less, it is always in lean burn getting over 60 mpg.
The VTEC-E is based on engine speed only. If your car is running below 2500 rpm, it is using 12 valves - above 2500 rpm, 16 valves.
Lean burn is determined by the ecu and there is no indication of it. It is definitely not related to VTEC or the shift light. It doesn't happen with the throttle closed (idling). It occurs when you are driving with the throttle only slightly open and with sufficient manifold vacuum. I had a trip computer that would display instantaneous fuel mileage, so I could tell when the car was in lean burn. Lean burn is detectable. When cruising you will notice the engine lose a little power (maybe even stumble) and you have to give it a little more throttle to keep it going, that is when it's going into lean burn. In 4th or 5th gear, at a steady 45 mph or less, it is always in lean burn getting over 60 mpg.
You are correct, however from the original posters description I don't think he has an hx model with the d16y5
If he has a d16y5 motor, the engine runs on 12 valve mode at idle