My factory 90 Civic has a problem that seems to become more pronounced after warmup. It hesitates / stumbles under light load acceleration at partial throttle. It operates great at idle, heavy loads, more advanced throttle. If the car is moving at higher speeds say 40 and above and I accelerate with partial throttle under any load conditions even light the problem will not ocur (I cannot under any operating conditions duplicate the problem at higher speeds).

I told my Mechanic about the problem before my recent smog check (which it passed, although pretty high on the Nox: he says I'll need a new convertor soon) He replaced the O2 sensor with a Bosch one and when I went to pick up the car showed me a computer fault code of 16, this we found under the passenger mat by counting the flashing lite. His manual lists that code as an open or shorted fuel injector and he suggests the lower injector is bad.

Is there a way I can be sure of the injectors condition before replacing it ? Should anything else be eliminated as a potential source for the problem before injector replacement ?

Thanks for any help

 

If it wern't for that code I'd be pointing to the hot humid temperatures your car is ingesting. The hotter the intake charge the more pronounced that bogging at takeoff will be... It's just the nature of our torqueless wonder motors.

In any case, you referred to your car as a factory civic, so I'm assuming the car is pretty much stock. Although it's somewhat unusual to experience injector failure on a stock Honda (Non Forced Induction anyway, where you're driving the injectors at a high % of their duty cycle over extended periods of time) Injector failure is definatly a possibility.

Just to keep you from spending any unnecessary money I would first reset the ecu by removing the negative battery cable from the battery for a moment, then replacing it. That will clear the code from your ecu and get rid of the check engine light for the time being. After you've reset the ecu take her for a spin and see if the light reappears. If it does, replace the injector. If the light does not re-appear, but your bogging problem is still there, try taking the car for a spin on a cool night and see if it improves. If it runs better wothout bogging in cooler weather and the check engine light does not reappear I'd say you're all good.

 

If you are high on your NOx readings and have a stumble at light throttle you could have any of the following problems: advanced timing, lean mixture, excessive carbon buildup (havent seen this yet), poor engine cooling, inaccurate TW (coolant temp) sensor, spark plugs too hot, cheap gas, bad distributor, poor ignition components, the list goes on. Your code 16 most likely has nothing to do with this problem. Code 16 will only be stored during a HARD failure- if the car occasionally wont start- your main relay will be the culprit. If you crank long enough when your car wont star and the check engine light comes on with a code 16 this is because the main relay is not working- leaving the circuit to your fuel injectors open. On your particular model the fuel pump is also on the same circuit and it won't be running. A code 16 won't give an intermittent driveability problem- the car won't run.


[Modified by fixhondas, 11:31 PM 7/25/2001]