Quote:
Originally Posted by firehawk618
I am really interested in that engine. I would seriously swap one in IF I could get the correct ecu.
From what I understand it would never pass obdii emissions testing in the united states but I am not positive.
Chryslerkid, I was under the impression our engines "y5" operates in 3 valve mode upto ~2800 rpm's then will go into 16 valve operation if you're heavy on the throttle.
Otherwise it stays in 12v generally.
Again, this is only what I have read and so far it seems like the y5 ecu operation is a ton of speculation and very little fact.
I wonder if the official Honda manual for the y5 publishes the ecu's logic for troubleshooting?
If you guys want I will wire in a temporary indicator to my vtec solenoid and report exactly how it operates on my car......
EDIT: If someone is good at arduino code and can edit the mpguino code to add 1 or 2 inputs........I would wire the vtec + upshift to that vs the dash lights.
I ended up pulling my upshift light out. Very annoying! Especially when it's occupying a full light therefore bright vs the real upshift arrow which is mostly blacked out. The other issue with that light is if you follow it there are times that will keep you out of LB. I ignored it and was able to get LB as low as 28 mph and the whole time the ECU was suggesting an upshift which would have kicked out LB for sure.
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You're reading voltage under 1v aat the secondary oxygen sensor to determine lean burn correct?
As far as 3 valve operation on the y5 I have no idea, the upshift light could be saying when the car is out of 3v operation for all I know. Vtec engages when the car is in 4v (16v) mode and opens the valves at a more agressive duration than normal.
It would be great to find the actual honda ecu program schematics and protocols however honda created these cars during a time when gasoline prices were very low and as a result the class leading gas mileage was an after though to selling mass produced vehicles that already were very fuel effecient.
Vtec on the hx is triggered at a higher rpm than the ex model, and I do know the vx would use 3v mode in all gears but honda received complaints about the abrupt change from 3v into 4v into vtec. So I assume 3v mode in the hx is only in lean burn conditions to make the car more friendly to drive in lower gears without the abrupt changes in the power band
I spent a few nights reading up about the man who engineered "lean burn" but I can not recall any spefic functions or features besides creating a swirling effect by only using 1 intake valve allowing the 2 exhaust valve to release the heated exhaust much more effeciently allowing the car to run leaner without the negative side effects of added heat and strain on the valve train