I have an 89' CRX with a boosted B16a.

I just put a set of high impedence(12 ohm) 550cc mazda injectors in the rex instead
of a set of low impedence (2.5 ohms) 450cc mitsu injectors. I removed the resistor
pack when I did so. I also recalibrated the fuel maps in my ZDYNE gold by cutting
cycle time down to 85% (450/550=0.82~82%).

The problem is that the car runs choppy at idle. It still runs fine under mid to high
boost levels. I don't have any vacuum leaks. The injectors were just cleaned and
calibrated. When the car is idling warm it smells perfect. I even bumped up the
duty cycle by 5% to see if it was just burning to lean at idle for the bigger injectors (I
was at 14.4 AFR before the 5% increase). The car now smells slightly rich at idle
and still runs choppy at idle.

Is this an injector driver conflict with the high impedence injectors despite the
removal of the resistor pack??

Has anyone else got away with this?

Any help would be appreciated.

Take care,

Harold

 

high impedence is saturated and you need to splice the wires from the resistor box and hook them to the injectors.

 

They have been spliced. Otherwise the car wouldn't run.

Am I missing something here??

 

So your running 85% of a 550 injector right. Well by my calc thats still a 450cc thats pretty high. How much H/P are you planning on?? ( I know better safe then sorry) Have you tried http://www.theoldone.com/articles/regulator/ it tells you how to drill you FPR to relieve pressure in the FPR, caused by large injectors and giving you a bad idle

 

My base maps were based on 450cc injectors but these top out at around 14 psi of boost. I run 14 psi routinely on good gas and have been doing so for over a year. The reason for the 550cc injectors is obviously to run more boost. The more power, the better! (safely that is)

So, yes...you are correct, it does work out to 450cc and that isn't the problem. Its not a pressure issue either, I am running stock fuel pressures at standard idle vacuum and 0 vac, with an upgraded fuel delivery system and AEM regulator.


[Modified by CRX-Freak, 12:29 PM 3/4/2003]

 

since u doing a hybrid of injectors satured of high impedance running without a resistor on a hacked ECU to run those injectors... u should have expected that.... cant expect a perfect cycle.... maybe they are a lil too big,......the Zdyne handles 450.. but 550 are 100cc more.. and thats a lot.....
i say the timing of the injector on idle... its going to be not accurate on that specific injector with those maps....