I'm working on a '97 450 for a guy. The truck has supposedly had new injectors put in a while back. The trucks missing like crazy. He had a buzz test done and 3 is real quiet and 7 is completely dead. He had me take the valve cover off to put harnesses and a gasket on it. I checked the resistance once I had them off and they were all either .1 or .2 ohms. He had me put the harnesses and gasket on anyway. I just got it back together and nothing changed. I pulled the plug off the IDM and checked the resistance of the wires between the IDM and the valve covers for cylinders 3 and 7 one was .5 and one was .6. Is this too much resistance or is that in spec? Any other ideas? Thanks a lot for any info yall have thanks

 

what was the concern before the injector replacement? a quiet injector is a bad injecotr when it comes to a buzz test. a 7.3 buzz is loud and obnoxious

 

not sure what the issue was with the injectors before. All he knows is that they were replaced about 10k miles ago. I did just do another buzz test though with auto enginuity and 7 is making noise now but its much quieter than the rest. 3 and 7 are both quieter than the other ones

 

quiet injecotr solonoids= no good.

 

So you're saying that if they're woking a little but quiet it could be nothing other than the injector itself? Are the solenoids replaceable seperate from the injector?

 

Have you measured the poppet clearence?...

Have you watched them while engine running ,(oil spouts) ?...

 

Yes! And to help isolate the problem you can swap solenoids from the injectors that are firing to the ones that aren't. That way you'll know if the problem follows the solenoid or stays with the injector.

 

To add to Rodneys post ,,some ...pics ...of dissasembling them

 

No I havent watched them while running or measured poppet clearance and I'm not sure how to do that. But to switch solenoids those first four screws on top are all I'll have to take off? Also, I'm assuming theres no reason I have to remove the injectors to switch the solenoids right?

 

Also, do yall think theres enough slack in the UVC harness to switch the plugs from one injector to the other to test the wiring?

 

There are other reason a buzz could be quiet like Rodney and Rick are talking about. It the poppet screw is loose the plate or screw could be hitting the solenoid before it has a chance to lift.

To swap solenoid yes there are just those 4 screws on top and the soleniod lifts off. To measure poppet clearance I will provide a link. You just need some .002-.004 feeler gauges once the solenoid if off.
DIY-Injectors.com

Click on the FAQ/tech link and go down to where is says "how to check armature clearance" and click the link.

 

Well I switched the wires around and the quiet buzz stays with the suspect injector, so I guess I've got 2 bad injectors. I'm not gonna mess with switching the solenoids around because the whole injector is under warranty. Now I've just gotta get them out and have the guy send them off. I may have some questions about removing the injectors

 

Well I read 2 different writeups on injector removal. DIY injectors and beans diesel performace. DIY says to drain the crankcase, drain the HPOP and drain the oil galleys. I like Beans Diesels writeup a lot more because they're saying to just let everything drain into the back two cylinders as you pull the injectors and then take out the glowplug and crank the motor to clean it out when your done. I'd like to just do that, but do I really need to do all the other stuff? I'm only gonna be taking out 3 and 7. Also, is the copper washer thats on the bottom of the injector reusable?

 

You still have get the oil and fuel out of the cylinder when you pull an injector. I have pulled 1 or 2 injectors and when I reinstalled the injectors I removed the glow plugs for those cylinders, pulled the #9 MAXI fuse under the hood (to keep the IDM from firing) and then "with a remote start switch" NOT THE KEY, I bumped the starter over to clear the cylinder, make sure you have a heavy towel over the glow plug holes (the fluid comes out under high pressure). Of course this is not the correct recommended shop manual way, so do this at you own risk.

The copper gasket (washer) is a one time use crush gasket, not reusable.

 

So you're saying you dont pull the galley plug or drain the HPOP before you pull the injector? Also, do the ford and international dealers usually keep the copper gasket and injector o rings in stock?