My 2014 Chrysler 300 3.6 was setting a code P0305 for miss on cylinder. I found that the injector on that cylinder showed high resistance of 27 ohms. I believe that is my problem. What does this high resistance cause the injector to do wrong ?
Does it change pulse width longer or shorter ? Does it open more or less ? Rich or lean ? Thanks, Old School ,trying to educate myself in a more modern world ! I am repairing . Thanks !

I would think a high resistance injector would be slow to respond to the opening and closing instructions from the computer. I would replace that injector as soon as possible. If you keep running it, it may damage the computer and the O2 sensor(s), at the very least, a v6 with a cylinder misfire can't be much fun to drive.

Can anybody explain how a high resistance load could harm an automotive computer?
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Don't know, but my son had to replace the computer on his Hemi Durango because it kept giving him a code for the same injector with high resistance. The problem was present when he bought the truck used. It may have been the computer at fault all along, but it started with misfire (you could feel as the motor idled) that would be gone after the injector was swapped with another, cleaned, or replaced, and would come back after a few months. He replaced the wiring to the injector and everything until he finally replaced the computer.

What is the spec for injector resistance? Typically low resistance will shut down the injector driver in the computer because current flow increases with lower circuit resistance(current limiting drivers) I have not seen issues with high injector resistance...not to say it won't cause issues. The spec will tell you if there's a problem or not.

If I remember correctly injectors come in both high and low impedance rating, I'm also under the impression all of them operate off of - 5.5 volt direct current, correct?

I did change the faulty injector and car runs perfect now . 5 of the injectors tested 13.5 ohms ( cheap meter may not be in great calibration ) and the bad injector was 27 ohms . I am just trying to understand a few more details .

Injectors use a coil to open the pintle. Increase resistance in the circuit would require more current to open the injector because that added resistance is siphoning off some current. If the injector drivers in the computer have a current limiting feature then the injector won't function properly because they do not have enough current to open. If the computer does not have a current limiting feature then eventually you burn out the driver.

Had a similar issue with an offbrand car. Turns out, in my case, it was a dirty connection at the injector.

I think you have it backwards. Increased resistance will not require more current.

Congratulations on the fix!

Any debris on the “catch screen” at the top?

Any sign of corrosion on the electrical contacts?

Got any urge to cut it open and post pics?

Lol, you keep on believing that.

A coil REQUIRES a certain amount of current to function properly. If you increase the overall circuit resistance then the amount of TOTAL circuit current needed to energize that coil goes up, otherwise the coil does not work properly. In a circuit without current regulation the added current is available, up to the point something goes up in smoke. In a current regulated circuit the coil fails to operate and you get a misfire, but no smoke.

Looked in inlet side of faulty injector and did not see debris . There was no corrosion on contacts . I would like to cut open this faulty injector and see what is going on inside , but have to get time to attempt .

I guess you have disproved Ohm's law.

Congratulations.

Ohm's law
PHYSICS
a law stating that electric current is proportional to voltage and inversely proportional to resistance.

Exactly! Decrease resistance...increase current flow. Been proven many times and the reason all late model computers have current limiting drivers. They are in place to protect the computer against shorted circuits...you know the circuits that decrease in resistance.

When it comes to controlling a electronic fuel injector several things come into play, mainly how fast and how long can you accurately do that in each pulse time. Another thing is the bigger injectors have heavier parts (the pintle) inside so they may take longer to open and close completely compared to a smaller flowing one, I think, maybe