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D4 7U injector service?
D4 7U injector service?
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2 years 10 months ago #234455
by Zzzopp
Injector questions... my D4 7U has a slight miss at idle, looking for information on pulling injectors to inspect/service. Are these able to be gone through on the bench or do I need to drop off at an injector shop? Thanks.
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2 years 10 months ago #234458
by neil
You can check some things on the bench such as spray pattern and dribble if you have an injection tester. You could also check basic pump operation and configuration first. If you pull the exhaust manifold off or use a stethoscope, you can check which cylinder is missing, then move the injectors and pumps separately to isolate the cylinder.
You can fit new nozzles to the injectors - they're under $20 each from your dealer so that's an easy step. To move injectors / replace tips, you'll need the injector nut removal tools and a set of o-rings. Be prepared for the possibility of needing to replace some precombustion chambers, and maybe have someone tee'd up to send you an injector or two if it's determined you need them.
Cheers,
Neil
Pittsford, NY
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2 years 10 months ago #234462
by bursitis
you can remove the injector and injection line. turn the line to the outside reinstall the injector onto the line and then use the pony engine to turn the big engine while you observe the injector for malfunction.
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2 years 10 months ago - 2 years 10 months ago #234473
by josh
The U series tractors have the capsule type injectors/nozzles, which are not easily tested off the cat for function. Usually the way to deal with a suspect injector, is first determine which cylinder is missing by cracking the injector lines one at a time until you locate the bad cylinder, then you can swap the injector on the bad cylinder for a good one and see if the problem follows the injector, if the problem is the injector/nozzle, replace with new, preferably all. If not the injector next things to consider are, the injection pump for that cylinder, valve settings and condition, pulling injectors is not too hard
Last edit: 2 years 10 months ago by
josh.
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2 years 10 months ago #234482
by josh
Here are the pages from the service manual for the D315 engine in your tractor.
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2 years 10 months ago #234499
by wimmera farmer
Heat gun on the exhaust manifold will often show a cooler temperature for the offending cylinder. Very easy initial check no dismantling required.
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2 years 10 months ago #234561
by bernie
Hey Gary-
I’ve watched the video three times. Great info-another useful resource you’ve shared. Thanks!
Cheers-
Bernie
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2 years 10 months ago #234600
by edb
Hi Team,
checking exhaust manifold port temperatures is not always straight forward, as in a 4 cylinder engine for example the centre 2 ports will be slightly warmer than those at each end due to the end cylinder gasses passing the centre ports as well. Also the port nearest the fan will be cooler than the one at the rear due to the fan airflow having a cooling effect at that port--however a lazy or misfiring cylinder will generally be somewhat cooler than the others.
After some practice it is possible to use the infrared gun successfully to troubleshoot for lazy cylinders bearing in mind the above variations.
Cheers,
Eddie B.
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D4 7U injector service?
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