injection timing
07-06-2011, 08:40 PM
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Staging Lane
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injection timing Is there a way to change the injector timing related to crankshaft angle. Trying to get my car to idle at stoich instead of rich. I have a 236/236 114lsa cam in the car right now
07-07-2011, 12:15 AM
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There's a big thread over at HPT that discusses injection timing and improving low-end performance...
http://www.hptuners.com/forum/showth...jection+timing
Net results on a slightly larger cam showed increasing the injection timing tables from there stock values of 5.55 (at operating temps) to ~6.5 netted a nice gain under 3K RPM. You might not need as much of an increase. But, don't expect this to cure the lean reading you'll get on an O2 sensor.
AFR's should read leaner than stoich at idle. Getting the right fueling with a WBO2 is only going to confuse you because your cam has 8 degrees of overlap. That means, there will always be a small amount of unburnt oxygen passing thru into the exhaust, whether your fueling is rich, lean, or spot on at idle. I'd probably expect it to be somewhere in the mid 15's when you do get it right. That takes you to the next problem....running closed loop. O2 sensors will want to flood the motor until the unburnt oxygen is drowned out enough to stop the fuel trims from rising.
For me, the solution I chose was to run open loop. You'll need to figure out what's best for you...
http://www.hptuners.com/forum/showth...jection+timing
Net results on a slightly larger cam showed increasing the injection timing tables from there stock values of 5.55 (at operating temps) to ~6.5 netted a nice gain under 3K RPM. You might not need as much of an increase. But, don't expect this to cure the lean reading you'll get on an O2 sensor.
AFR's should read leaner than stoich at idle. Getting the right fueling with a WBO2 is only going to confuse you because your cam has 8 degrees of overlap. That means, there will always be a small amount of unburnt oxygen passing thru into the exhaust, whether your fueling is rich, lean, or spot on at idle. I'd probably expect it to be somewhere in the mid 15's when you do get it right. That takes you to the next problem....running closed loop. O2 sensors will want to flood the motor until the unburnt oxygen is drowned out enough to stop the fuel trims from rising.
For me, the solution I chose was to run open loop. You'll need to figure out what's best for you...
07-07-2011, 10:32 AM
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I have a 2bar speed density tune using efilive on the car. I figure if i change the injection timing i wont have to run to rich of an idle a/f to get the car to idle descent. If I command anything less than lamba 1 then the o2's will stop making any ajustments at that rpm and map correct.
07-07-2011, 02:24 PM
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I have a 2bar speed density tune using efilive on the car. I figure if i change the injection timing i wont have to run to rich of an idle a/f to get the car to idle descent. If I command anything less than lamba 1 then the o2's will stop making any ajustments at that rpm and map correct.
