Well, it looks like my rash of bad luck with this Jeep continues. I have suspected an injector problem for awhile now but haven't had the time or patience to confirm it. I finally bought (much to my dismay) one of those Chinese garbage return flow kits and checked the injectors this weekend. The initial results are not promising.
So the vials are supposed to be 105ml each. I haven't confirmed actual quantitative measurements but from a quick glance it appears to be
roughly 58ml, 68ml, 79ml and 63ml for injectors 1 through 4 respectively. Those are pretty wild results in my opinion. Now, this was a COLD test. I need to go get supplies for an oil change so I'll test again at full temp and see what I get. This seems kind of dooming regardless of the conditions though, no?
Now, it is very possible that the injectors have been this way since I bought the Jeep but I am concerned that some of my habits my have contributed to them getting worse. I use Lucas diesel additive at every fill up (or every other, sometimes). When I started having concerns about the injectors I started using Marvel Mystery Oil in the fuel tank because it is considerably more solvent than Lucas, in hopes that it would help clear the injectors. I suspect that it may have done the opposite. After a few weeks of that I noticed really poor mileage and the engine wasn't running right so I changed the fuel filter and drained the old one into a clear pitcher and it was almost brown! The MMO had released so much crud from the system it clogged the filter. I know the OEM filter caught most of it, but there must have been a ton of fines that made it through with that much in the filter itself. While one grain of sand can't dam a river, many millions can, so to speak. This was almost a year ago and things haven't gotten noticeably worse since then so it is tough to say if any of this is true. Just hypothesis. The long and short of all this is that I am highly recommending that anyone who is using or considering using MMO or any other "high-flash" additives, to install the 2-micron fuel filter setup first, and check/change it often. I have the kit sitting in the garage waiting to be installed, which may happen sooner rather than later now, considering my findings and the cost of injectors. As a side note, I usually fill a new filter with Power Service "White", run the engine for about 30 seconds to clear the old fuel out then shut it off for about 30 minutes to let the injectors "soak" in the PS. I have never noticed any positive or negative result from that, but I figured it might come up here as something to try.
So now for the tough part. What are my best options assuming that the hot test comes back with the same result? Most of my reading has concluded that back-flushing diesel injectors doesn't work most of the time and it can't be done at home anyway. I don't have any reliable injector services near me that I know of, just one that has already screwed me once. There are likely tons of them in Phoenix, but I despise that city. This is my daily driver, so I can't ship them off to be tested and wait a week or two for them to return. Is a visit to the dealer in my future? I have heard of (and once had a guy perform) an injector test with the injectors in the vehicle. I assume that was just turning off the injectors in sequence and monitoring the rpm for fluctuations? Is that going to tell me anything the flow test hasn't already? What would you guys do?