19# injectors sans chip

[thedeal]

I am curious, can I run my m20b25 with 19# injectors w/o a chip for now. I plan on chipping it I just don't have it at the moment But I have the spare time to do the injector swap later this week. Will this Eff up my system?

Thanks

[Wh33lhop]

Well yes, you will just run rich as sin.

[884door]

Pretty sure it'll run like crap at first but I think the ECU will adjust and make it work.

[Wh33lhop]

Pretty sure it'll run like crap at first but I think the ECU will adjust and make it work.

It can only adjust within certain parameters.

I doubt it will run as well as with stock injectors, even if you give it ten years of adjustment time. But it will be bearable for the time being.

Just cough up the cheddar for a Mark D.

[tjts1]

If the M42 can handle 22 and 24# injectors without running "rich as sin" on the stock chip, I think you'll be fine with 19# injectors in your M20. You'll only run rich in open loop which is exactly the point.

[884door]

It can only adjust within certain parameters.

I doubt it will run as well as with stock injectors, even if you give it ten years of adjustment time. But it will be bearable for the time being.

Just cough up the cheddar for a Mark D.

I agree 100%

[nando]

If the M42 can handle 22 and 24# injectors without running "rich as sin" on the stock chip, I think you'll be fine with 19# injectors in your M20. You'll only run rich in open loop which is exactly the point.

the M42 comes with 19# stock though

M50 injectors (17#) are a better match for an otherwise stock M20, plus you still get the superior 4 pintle design.

[Kruzen]

I run it and haven't had the time/opportunity/placetowork to throw in the m30 afm and buy a markD chip.

I have pretty horrible gas mileage around town, highway is still good, haven't really noticed any gains, when the ECU is acting happy its a bit peppier than I remember it, but it could all be placebo.

/shrug.

[zaust]

The m30 afm will make no difference at all what ever map or injectors your running. stick with the stock injectors and get a map/chip and a big bore throttle body, much more benifit to you. You will also see a big benifit from removing the water from the bt too, just join the pipes together.

[AlarmedBread]

It will run like shit, this is w/ m30 afm, but the stock afm was the same, very rich, no power, very poor fuel economy. Wait to do both injectors and chip at the same time. Alternatively you could try 19lbs + e85. I have been running that for a while without problems, but have no conclusive results or a dyno.

[deathtomine]

bt???

[mojorising]

The m30 afm will make no difference at all what ever map or injectors your running. stick with the stock injectors and get a map/chip and a big bore throttle body, much more benifit to you. You will also see a big benifit from removing the water from the bt too, just join the pipes together.

I think he means tb as in throttle body? Those of us in warm climates can probably take the throttle body coolant lines off, I am pretty sure they are only used to keep the throttle from freezing in the cold temps. That and they probably warm up the intake temp a bet once the motor is warm.

[nando]

I think he means tb as in throttle body? Those of us in warm climates can probably take the throttle body coolant lines off, I am pretty sure they are only used to keep the throttle from freezing in the cold temps. That and they probably warm up the intake temp a bet once the motor is warm.

the temperature most likely to see ice formation is apparently ~70 degrees.

also, with as small of a surface area as the TB is, I doubt it would make any difference. the air is moving through the TB at a high speed and into an intake manifold that is just as hot and has lots more surface area.

[T Verdier]

So the ecu doesn't adjust for the injectors because they are design 2/3 and not design 1 like the stock #14

[nando]

nope, that has nothing to do with it

design 2/3 just have more pintles and a far superior spray pattern

electically, they are exactly the same. The ECU cannot tell them apart, except that with O2 sensor feedback it has to dial back the pulsewidth to reach it's 14.7:1 target.

the ECU has long term and short term fuel trims. the short term trim adjusts the injector pulsewidth in real time to keep it as close to 14.7:1 as possible. the long term trim adjusts a global base pulsewidth value based on how much it has to adjust for the short term trim. It only works with a functioning O2 sensor.