Injectors...

[bluescapegoat]

Ok I bought an ST185 recently that was listed on this site. It had a LOT of problems. I have fixed most. But the big one I'm having is it's only running on cylinders 1-2-3. I pulled the injectors to send them off to WitchHunter for cleaning and #4 isn't even the same color. Wtf? Has this single injector been replaced in the past, is it discolored from not firing, was it defective to begin with, or maybe just a different batch of plastic in manufacturing and it's pure coincidence it doesn't work? I don't want to spend $100 to have 3 injectors cleaned when one is garbage anyway. I'd happily order all new ones, but I like the thought of keeping running on the factory originals...

[klue]

probably a wiring issue, did you check that all the injectors are getting a pulse?

[bluescapegoat]

No, I didn't. I'm learning as I go. After further studying the injectors, #4 is definitely a different brand, quality does not look nearly as good.

All I checked was the resistance in each injector.

What would be the easiest way to check that they're getting the appropriate signal?

Also, might be worth noting that I am not getting any engine codes

[klue]

if you have everything hooked up, you can get whats called a "noid light" it clips into the connector for the injecot and lights up when the injector gets a pulse. After that its just a matter of cranking it over and seeing if it lights up.

Second to that if the car will run on three cylinders. you can disconnect each plug until you find one that doesnt make a change in the way the engine runs. Then you know which cylinder isnt working.

[bluescapegoat]

Got the injectors back on Monday, they were all good, but did clean up a little.

I'm got a friend coming over on Saturday, going to do some diagnosing.

Thanks for the help.

[MacGyver]

What part of OH are you in?

[bluescapegoat]

Brunswick.

I was just starting to reinstall the injectors and I can't find the fuel rail isolator for the #4 injector. Either I lost it, or its been missing all along. Seems like that could explain the issues ive been having.

Off to the dealership in the morning.

[bluescapegoat]

Injectors are fine. #4 was not getting a signal. Solenoid resistor tests fine. Wires from injector to ECU test fine. ECU not sending a signal to pulse the #4 injector. Looking for a 91 ECU.