Fuel on top of head

TKB4 · **Posted:** Sat Jun 05, 2021 1:32 pm

I haven't had this jeep where I could drive it for a while and recently replaced injector number 3 to get it running. After replacement it cranks and runs fine. I noticed a diesel fuel smell. At first I thought it was from some fuel evaporating off head when I bleed the fuel head. It continued and I did some investigation and found clear diesel fuel around the injectors.
I put soapy water around the injectors and started it up but could not see any evidence of leak from around any injectors but couldn't see number 4 real well. I then snugged the fuel line fittings on injectors and rails. I did NOT hold the injector still with a wrench but they were installed and held by the crowsfoot piece.
I then used air to blow dry the head. I then restarted engine and observed the injector area for a minute or two and did not see any fuel leaks.
I then drove it about 40 miles pulling a trailer and 4 wheeler and started noticing the diesel smell again . When I got home there was quite a bit of clear diesel that seemed to be mainly around injector number 2 but of course there was some around 3 and 4 which I believe is just the fuel flowing down to them. Interestingly there was also fuel on the driver side of the head above the ridge toward the fuel rail. So it appears that fuel is either leaking from part of the injector itself or fuel rail/ fittings. The fuel rail seems to be much less likely.

I have wondered about several things. How to troubleshoot the source. Is there only a leak under load when ? the fuel pressure is higher? or maybe only when RPM increased ? It seems as though it may be the injector itself leaking . I also wondered about return fittings or line leaking even though it appears ok.

I plan to
1. Reclean the head area
2. get someone to rev up engine and observe
3. If nothing seen try wrapping the number 2 injector with a shop rag and tie or tape it in place as well as separate wrap around the return line as well as I can.
4. drive it a few miles and see if rag is wet or whether fuel still collects on the valley toward the fuel rail.

Anyone have any other ideas. I dont see how I could tighten any of the injector sections since it would change the angle of the fuel line fittings etc.

If I can't prove its the return line I suppose I will just change injector number 2 and see what happens since I have some extra injectors.

TKB4 · **Posted:** Sun Jun 06, 2021 10:10 pm

I did the trouble shooting and narrowed it down to the fuel return line but there didn't appear to be any crack and the clip was in place . I ended up removing the clip puled the return fitting up off injector and lubricating the plastic fitting with some no-ox I had handy and replaced it. There was a definite click in place and replaced the retaining clip. Restarted and revved up some and no evidence of leak then drove it about 10 miles and no further evidence of leak on return. I thought sure it would be a crack in the fitting that only opened up when hot or driving etc but it appears that fixed it. Not sure how clip went on with the fitting ? not in all the way or maybe it just wasn't seated well enough.
Note it is MUCH EASIER to replace the return fittings into the injector with a lube of some kind.

Fuel on top of head

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