Injector testing
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Injector testing
I recently bench tested all of my injectors with a rotunda bench tester here at work. All had opening pressures around 1600, and all had similar spary patterns which was a straight angeled stream when pressed hard. I also noted a dribble at 100 to 200 psi before opening when held at pressure. I replaced 2 of the worst dripping ones, but have always had a ticking noise from inside the truck, like around the bellhousing area. when outside i cant hear it, and the truck is now running great. good oil pressure, etc. I have just been writing it off to an exhaust leak, until last night it seems much loader. Not a knock, more of a tick. Seems like it was worse right after a higher rpm drive, and i can only hear the noise at idle or slightly over that, i dont hear it as-bad during higher rpms.
Can anyone offer some suggestions of what to look for?
Can anyone offer some suggestions of what to look for?
Posting Guru
Joined: Sep 2002
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From: Northeastern Pa - USA
Could be a fuel pressure knock that you are hearing from inside the cab. Sometimes when outside or under the hood you dont hear it because of other noises interferring. If you tested that nozzles and are comfortable with the results, hang in there with what ya got. Grandpa always told me, dont go looking for trouble.
Posting Guru
Joined: Oct 2003
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From: Monroe, WA
I was just reading in my International 7.3 manual today about injector testing. It said the new pressure should be 1875 and the low limit is 1425. It also mentioned not to worry about the spray pattern or even how the fuel squirts out. As far as leaking tips go, it said to bring them 200 psi from pop pressure and watch the tip. If a drip forms and drops off within 5 seconds, replace it. I thought it was an interesting read.
Now, for your in cab noise. Is your throttle cable rubbing on the rear injector line? Most cables do, and most have some foam rubber slid over the cable to keep the injector pulse from echoing into the cab. Check to see if yours is missing or it's partly chewed off letting the cable touch the steel line. Then just do whatever you can to keep it touching. If you can change the sound this way, it might even be worth putting a new cable in. Just a thought, it took us a while to find the first time.
Now, for your in cab noise. Is your throttle cable rubbing on the rear injector line? Most cables do, and most have some foam rubber slid over the cable to keep the injector pulse from echoing into the cab. Check to see if yours is missing or it's partly chewed off letting the cable touch the steel line. Then just do whatever you can to keep it touching. If you can change the sound this way, it might even be worth putting a new cable in. Just a thought, it took us a while to find the first time.
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Joined: Sep 2004
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Spectramac, 100% right. I read elsewhere on here about that, and checking Saturday. My throttle cable is worn 1/2 way through. I pulled it away and no more noise. Im gonna put some rubber fuel line over that area, and keep trucking, when i hear it again, ill replace the rubber.
Thanks!!
Thanks!!
