I am trying to diagnose an CEL code 51 on a 1990 300zx N/A auto.

I have gotten as far as testing the injectors with a multimeter using the ohm setting. It says each injector--if good--should read 11-12.5 ohms.

So I set my multimeter on it and every time on 3 different injectors it just pegs out the needle. I know for a fact I must be doing something wrong.

Here is the injector. I touch one of the connector needs from the multimeter to one of the injector connector prongs, and the other to the other.


Here's an image of the multimeter I'm using.





I'd really like to be able to diagnose and fix this situation myself, so any help on how to correctly measure the resistance of these injectors would really be great, thanks everyone. Nice to meet all of you by the way.

 

how does the car run ? i pref. to use auto range multimeter . you can also get an inj. pigtail from parts store to use as a tester . this way your fingers dont touch your test leads ( false readings ) . if the engine is misfiring , you can disconnect ignition coil connectors , one at the time , to narrow down which in inj. you need to test . easier to disconnect coil connectors than injector . good luck .

 

The car is my brothers so I never really daily drove it to find out, but from his account the car would run GREAT for a random amount of time, like weeks or months, then for a random amount of time it'd idle and run like ****.

Right now it seems to be in the "****" phase.
Thanks a ton for the response!