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cylinder 5 not working


MiniMe

Active Member
Joined
Aug 7, 2013
Messages
36
Vehicle Year
1989
Transmission
Automatic
recently bought an 89bonco II with 2.9 automatic. after new fuel pump/sending unit, and new screens and orings for the injectors i got it fired up. noticed low oil pressure so i replaced sending unit. problem fixed. Got another problem now.. cylinder 5 is not working... im getting 140 lbs of compression and spark. i pulled plug wire off while running and made no difference. The injector is ohming at 15.6 ohms. I am also getting an injector pulse. wondering if the injector is bad even though it ohms good. any input?
 
Last edited:
Honestly, The injector is the only thing I can think of...It's a shame since you just did all that work. It's not like fuel isn't making it to the injector because the other injectors are all working and cyls are firing.
 
Does the #5 plug appear to be wet with fuel? Could swap a couple of injectors around and see how she does.
#5 spark plug is dry and looks brand new where as plugs from the other 2 cylinders looked like they had been working and burning fuel
 
Since there is more to an injector that just an electromagnetic coil it is very possible for it to ohm good and be bad.
 
#5 spark plug is dry and looks brand new where as plugs from the other 2 cylinders looked like they had been working and burning fuel

Dry cylinder and cold engine would mean injector issue.

You can use a small hose and listen to that injector, see if you hear the steady "tick, tick, tick" while engine is running.
I have read of people pulling the electrical connector on an injector and applying 12volts and ground to the injector to force it open longer to "clear it out", never tried myself, I would think you would need a resistor to lower the voltage a bit but have read it works with direct from battery power, but don't leave it connected to long, a second or two.

I had 1 bad spark plug on a V6, looked fine but was dead, I would swap plugs in #4 and #5 just to see if miss moves to #4
 

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