Upgrade or just a fail

[Justbadger]

If you bought new injectors and don't want to go back to your old ones than you will need a tune adjusted to suit. The1 (user on this forum) or MACE (forum sponsor) can probably do a tune to suit the different injectors.

The problem with fitting larger injectors and not adjusting the tune to suit is that you will have put considerably more fuel into the engine than required which has the potential to bore wash the cylinders (excess fuel running down the bores and washing off all the oil that lubricates the rings and makes everything slippery) as well as contaminating the oil/diluting it. You may have also potentially fouled the spark plugs.

Will the ecu not only spray in enough for the air spark that's coming in I thought...

 

[Immortality]

No. These PCM's use an injector constant (it knows how much the injector flows) and then using the MAF (to measure how much air is entering the engine) it calculates how much injector pulse width is required to achieve the target air fuel ratio.

For things like starting the PCM just has a table that tells it how much fuel to inject depending on engine temp, voltage, rpm etc. All these constants will be wrong for the larger injectors and will need adjustment.

IIRC standard 777 injectors (used in the ecotec motors from VT onward) flow 22lbs/hr. Those Super6 injectors flow 36lbs/hr so basically you are injecting about %38 more fuel than is required.

edit: fixed my bad maths....

 

[Pollushon]

Damages??

I doubt damages but you'll likely have more fuel in your oil than you might like

 

[Justbadger]

I doubt damages but you'll likely have more fuel in your oil than you might like

Ok so I've ran it n initially was smoky whitish colour. But went away now idles nicely like its cammed lol.. seems the more I run it the better it gets... do you know anything about holding revs over 2k for a minute to reset ecu or something?? Or is this just bs

 

[Justbadger]

No. These PCM's use an injector constant (it knows how much the injector flows) and then using the MAF (to measure how much air is entering the engine) it calculates how much injector pulse width is required to achieve the target air fuel ratio.

For things like starting the PCM just has a table that tells it how much fuel to inject depending on engine temp, voltage, rpm etc. All these constants will be wrong for the larger injectors and will need adjustment.

IIRC standard 777 injectors (used in the ecotec motors from VT onward) flow 22lbs/hr. Those Super6 injectors flow 36lbs/hr so basically you are injecting about %38 more fuel than is required.

edit: fixed my bad maths....

And that's a lot... recommendations for tuning??

 

[Immortality]

The1 (forum user)
MACE (forum sponsor)
Delcowizzid (forum user occasionally)

 

[Pollushon]

Ok so I've ran it n initially was smoky whitish colour. But went away now idles nicely like its cammed lol.. seems the more I run it the better it gets... do you know anything about holding revs over 2k for a minute to reset ecu or something?? Or is this just bs

It's mostly BS on an Eco of your vintage. You pull the battery for a minute put it back and drive it, the ECU relearns it's trims over time. Earlier models had some tricks to them around TPS specifically. It may seem to improve as once the O2's come online they will try to adjust for the extra fuel but they wont be able to pull it off. O2's run open loop until the motor warms up

 

[Immortality]

Yup. The 2K rev thing was to reset the idle on the earlier 3800 V6 motors.

The closed loop O2 adjustment or BLM has a maximum of 20% adjustment IIRC. Engine will go into closed loop mode once the engine reaches 30° C engine coolant temp and has been running for a set minimum time which I can't recall what that is off the top of my head. I think 120 seconds after starting.

The ecotec resets the IAC after each start if I'm not mistaken.

 

[Justbadger]

Yup. The 2K rev thing was to reset the idle on the earlier 3800 V6 motors.

The closed loop O2 adjustment or BLM has a maximum of 20% adjustment IIRC. Engine will go into closed loop mode once the engine reaches 30° C engine coolant temp and has been running for a set minimum time which I can't recall what that is off the top of my head. I think 120 seconds after starting.

The ecotec resets the IAC after each start if I'm not mistaken.

Thanks guys im gunna put old ones back in for now lucky I have a spare rail nnjust have to swap them back out... what would a tune cost me?? Roughly

 

[_R_J_K_]

Thanks guys im gunna put old ones back in for now lucky I have a spare rail nnjust have to swap them back out...

Just FYI, those injectors are not going to add a whole lot even with a tune. A bog stock Ecotec (or even a moderately modified/tuned N/A one) is not going to run out of fuel with stock injectors, and there's nothing that putting oversized injectors in will do for you. The days of restrictive carbies and poor fuel management are looong gone. Same deal with the throttle body largely. Any gains you see from a tune will be from changing from a stock/economy tune to something better, not necessarily because of the injectors.