Jeff_E Posted January 29, 2010 Share Posted January 29, 2010 Never thought I'd see the day after all I've been through, but I've got a feisty one now. 05 6.0 pickup owned by a local body shop comes in with the codes cleared. (they have already been in it). It is obviously missing on several cyliders and even stalled while pulling it in the shop. It feels like a fuel issue, and since I dont have any codes I decide to hook up the rotunda fuel pressure tester. I find the pressure at around 44 psi with the valve open, but I also notice a huge amount of air bubbles. I do the baloon test - Pass. I command the fp on with the engine off and it still aerates badly. I check the filters - dirty so I replace them. still aerates. I run the lines at the rear of the pump into a bucket of fuel and the aeration seemed to stop - or at least improve, so I pull the tank down and low and behild the pickup screen asy fell off and the pieces were laying at the bottom of the tank. All proud of myself for finding what seems to be a root cause, I put together a 2 part estimate for the customer: Part 1. Fuel delivery system repairs with new sending unit, filters, and regulator. Part 2. An estimate to replace all injectors incase they were damaged as a result of the aforemetioned. Customer approved part 1 and I performed it. Vehicle still ran like shit. Called customer back and they ok'd all 8 injectors which appeared to all be bad on the power balance, as relative compression was ok. I spent all mornig replacing all 8 injectors and my problem still persists. I get a horrible power balance while running, but relative compression is ok. fuel still seems to aerate slightly while running but I don't know if that is just residual air clearing out or not. My pids seem ok except load which is irratic at idle jerking between 55 and 80%. ICP seems a little high at idle at around 960. I swapped in a known good icp and ipr just for shits but no change. I also thought perhaps the ficm is messing up even though MPWR is around 48V and the buzz test passes, so I swapped a known good FICM but no change. Getting the customer to authorize what I have already done was like pulling teeth, and I don't want to call them back until I have an explination for my woes. Any help would be appreciated guys. ~Jeff Quote Link to comment Share on other sites More sharing options...
Bruce Amacker Posted January 29, 2010 Share Posted January 29, 2010 I'd look back into the possibility of fuel aeration. I had a 6.0 a while back that had a HFCM that was aerating the fuel and acting just how you describe. I disassembled it and could not find what was wrong inside, but a new HFCM fixed the aeration issue and it ran perfect again. (sidebar- this truck was under warranty and the dealer had it a long time without fixing it) I'd do a clear line test on the output of the HFCM and see what you have. Good Luck! Quote Link to comment Share on other sites More sharing options...
Jeff_E Posted January 30, 2010 Author Share Posted January 30, 2010 Clear line test FAIL. Thanks Bruce, I'll keep you guys posted... Quote Link to comment Share on other sites More sharing options...
Jeff_E Posted January 30, 2010 Author Share Posted January 30, 2010 New HFCM - Still aerates. Time for a break Quote Link to comment Share on other sites More sharing options...
Bruce Amacker Posted January 30, 2010 Share Posted January 30, 2010 That's not bad news, that's good news! If it's aerating, it's just a matter of testing the lines and pickup to find where the suction leak is. I'd cap the line and pressurize it with shop air for a test. You might end up pulling the sender back out. Good Luck! Quote Link to comment Share on other sites More sharing options...
Jeff_E Posted January 30, 2010 Author Share Posted January 30, 2010 Yeah, I think you're right Bruce. bypassed the tank and 2 lines rear of the hfcm with rubber hoses and a fuel bucket and it pretty much clears up short of a small stream of "champagne bubbles". when I hook the tank lines back up to the hfcm I get white foam. It's my quitting time now, I'll pick this up again monday. Quote Link to comment Share on other sites More sharing options...
Bruce Amacker Posted January 30, 2010 Share Posted January 30, 2010 I bet you have it fixed in a half hour Monday. Have a few drinks and sleep well! Quote Link to comment Share on other sites More sharing options...
ktmlew Posted January 30, 2010 Share Posted January 30, 2010 Yeah, I think you're right Bruce. bypassed the tank and 2 lines rear of the hfcm with rubber hoses and a fuel bucket and it pretty much clears up short of a small stream of "champagne bubbles". when I hook the tank lines back up to the hfcm I get white foam. It's my quitting time now, I'll pick this up again monday. Any time I had a vehicle come from a body shop my sphinctor would lock right up...can't count how many times I spent HOURS chasing down problems to find wiring badly mutilated from them straightening the frame or were pinched in the original crash. I learned to call the body shop and talk to every person that touched the vehicle. Offer to buy the guy that confesses "I saw some wiring that looked a little rough, but we don't get paid for that kind of work" a 12 pack...in your case you will likely find the fuel lines have been pinched somewhere...find out what exactly was damaged/replaced/repaired in the wreck... Quote Link to comment Share on other sites More sharing options...
Bruce Amacker Posted January 30, 2010 Share Posted January 30, 2010 Is there enough fuel in the tank? Wasn't there a TSB about senders showing half? BTDTGTTS, we put pumps in cars several times for empty tanks. I had a diesel Rabbit towed halfway across Ohio for an empty tank one time (girlfriend's car at the time). Brother...... Quote Link to comment Share on other sites More sharing options...
Jeff_E Posted January 30, 2010 Author Share Posted January 30, 2010 It has more than a quarter tank which I verified visually when I replaced the sender Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted January 30, 2010 Share Posted January 30, 2010 Sounds like he's got it narrowed down now. Good find! Just a side note, the new pressure and flow tester should have shown that there is air in the fuel. Usually you will see it when you have an injector leaking combustion gasses past the pintle but if you want to check the supply system for aeration simply install the flow tester, use IDS to command the fuel pump on (engine off) and open the valve, wait a minute or two to purge any air created by installing the tool or created by the engine. Observe the clear drain hose of the tool. If you have air then you start working your way back... This is something I look for every time I check fuel pressure and it is a good habit to adopt. That pressure and flow tool has proven to be quite valuable. Quote Link to comment Share on other sites More sharing options...
Jeff_E Posted February 2, 2010 Author Share Posted February 2, 2010 Well it's fixed!!! It seems that when you have about 50% gasoline in your diesel fuel it causes the fuel tank pickup strainer to fall apart and start sucking air. If I didn't have sinus polyps I'm sure that I would have smelled the gasoline. Never thought that handicap would screw me, but this time it did. The little orange plug fell out of my brand new sender and the entire black housing was loose on the tube. When I assembled it both were tight, but the gasoline must make them swell or dissolve enough to come apart. The original sender had the same orange plug laying at the bottom of the tank, but on that one, so was the entire black housing shown in the pic. It's all together with fresh diesel and running great now. Thanks guys! Quote Link to comment Share on other sites More sharing options...
mchan68 Posted February 2, 2010 Share Posted February 2, 2010 It's funny how we get burned that way, when all testing seems to pass, yet it still doesn't run right. The last one I had like this through me off a little bit too. What got me thinking, was how it sounded almost exactly like a 6.0L with an EGR valve stuck wide open as it idled (very quiet, almost inaudible CLACKING). THAT was when I had my brainfart, that I remembered the very first one I got burned on. Sure enough, a little sampling was all it took, along with the look on the owner's face when he grabbed the gas receipt and glanced at it in disbelief. Glad you got it fixed. Quote Link to comment Share on other sites More sharing options...
gasgasman Posted February 2, 2010 Share Posted February 2, 2010 I had a 6.4 kick my butt like that also.I installed a sender just hours before and the slight amount of gas ate up the "VV power valve". Ran fine, until I backed it out my stall. There is a slight slope behind my stall that was enough to lower the fuel level just enough to suck air. Always pour some fuel on the ground and see if it catches fire when lit. An gas present will burn right away. Quote Link to comment Share on other sites More sharing options...
Mbl35 Posted February 11, 2010 Share Posted February 11, 2010 Or when the diesel looks like vinegrette dressing sitting in a glass bottle. Quote Link to comment Share on other sites More sharing options...
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