My 300zx is misfiring, and I have narrowed it down to cylinder no 4 (mid cyl left bank). Have changed the coil pack and no success, and today also swapped the injector connector and cleaned the injector it self.

 

Tried with an "ohm meter" directly on the injector and I get a resistance of approx. 3.25 kOhm (yes kilo ohm). This does not sound OK to me, but is there someone that know what resistance that I should read.

 

If it is the injector, have anyone swapped no.4 using the "dremmel method" or will in be plenum off.

 

If it is plenum off, is there other things that I should get swapped at the same time. Also, any idea how long time it will take a garage to lift plenum and swap injector ?

I used the dremel method on a previous zed.With top quality tools, you dont have to remove masses of plenum. just enough to get straight on the screws, Little bop on the end with a hammer + they undo easy.

Mine took a bit of a wiggle + twist to get out + some vaseline eased the new one back in.

From memory I think the injector resistance reading should be around 12 Ohms, to be sure check the reading from one you know is working.

 

Link below for swap write up

 

http://www.300zx.co.uk/forums/showthread.php?t=117654&highlight=INJECTOR+OHMS

 

 

Jeff TT

I had a misfire, but it turned out to be a coilpack.

did you change the spark plug?

...After Dremelling and before removing the injector - remember to get the vacuum cleaner in there to remove all the swarf and generally clean the area before you pop that injector.

 

;-))

try a new spark plug mate first if y can, i've had an almost brand new one give me the same symptoms.....

....or just swap them around and see if the problem moves with the plug ;-)

Got this sorted with a new injector (from eBay US), as the old was dead. My local mecanic did the swap using the dremmel method, and it was easy according to him. I changed the injector connector at the same time as the injector to have a new / clean (no green gunk) electrical connection. Have worked fine since, and would definately look at the dremmel method again if I need to swap injectors later.