I have a JD 50ZTS with a Isuzu 4LE1 engine. It's been running fine but recently started to miss on one or more cylinders. Checked the fuel filters and they were fine. So I thought I would put a set of injectors in as a quick fix (not previously touched) and likely needed. While replacing the injectors the old #1 & 3 were almost completely clean while the #2 & 4 were black with a build up of carbon and soot. I'm not sure why some are clean and some are sooty. So the question is if the individual pump was stuck and not sending fuel to the injector would it cause this? I have not touched the pumps yet. has anyone had a similar problem. Thanks Dan
I can't remember, is the copper crush washer in the head bore at the very face of those or is it on the first step, or one of each? If it is at the very face, it could just be a little compression/soot bypassing the washer and dirtying the injector. I have replaced a few of those but it has been a few years, not a common thing to have to do.
Hi Birken, I send you Service Manual for ISUZU Engine 4LE1 . Regards
Hi Pud100, I send you Service Manual for ISUZU Engine 4LE1. Regards
Hello Birkin and Stefano Thanks for your help. I got busy over the holidays and I'm just getting back at it now. After the injector change it still had the low power and missing. The manual says the next step is to check for air in the fuel feed lines. This will likely be a spring job once it warms up a little. Thanks guys for your help and the manual. Dan
Is valve lash correct? Did you compression test while injectors were out?
I haven't checked the lash yet. I won't be using this machine until the spring as our winters are cold and snowy so that is on my list. Just thinking about it, it happened in the summer a couple of times just running like on 3 cylinders with power down and some vibration and then came back to it and all was good. Had no problem until the fall and it did it again and then next time I started it it was fine. The last time I used it it was fine then after about an hour it started running real rough and lots of vibration and no power. I had a tough time getting it to have enough power to get it out of the work area and finally had to assist it with the F450. Having said all that it is certainly an intermittent problem, or at least it was so I figured it wasn't a compression or a lash issue. It runs smooth and with power and then it's like pulling a plug wire (or two) off a gas engine. In all cases it's when the engine is hot.
Water in fuel is what it sounds like to me.
Hi Davey I checked both filters and no sign of water.
this is an old thread, but on my 50ZTS I had to take apart the individual injector pumps - right below the injectors - and replace the orings in them. 3 o-rings each. then I put on new copper crush washers across the common rails for all 4 of them and all 4 of the injectors. Also replaced all the rubber fuel line with new line. My hard start and hit/miss running all went away, engine sounds like new. wonderful runner now. TLDR: replace the o-rings in the individual injector pumps.