Air in the Fuel? Bad FPR? Bad FPRV? Video in thread.

[BoominSVX]

I'm kind of at the end of my rope with this truck. I usually test, hunt, dig and investigate... Even swap good parts to find problems. Winter is coming. I'm running like a fool and now the pig dies on me. First time ever that it wouldn't start. I'm running out of time. Let me back up a sec.


Bought it about 4 years ago. It had oil, coolant and diesel fuel in the same chamber. 5.5 gallons of it to be exact. New injectors were put in with old parts and nothing cleaned. I took a chance. It ran after they were in right, and I had a slight lope that has always kind of been there, but now worse than ever. I go through a 250g bottle of grey diesel kleen in about 3 tanks to keep it at bay. As of right now, I have absolutely no blowby at 245K.



Recently I was pulling a trailer about 5k lbs down the highway on level 4 on my edge. Knocked it down to tow and kept going. Ran out again (by run out I mean fuel limp because I haven't gotten the fass 150 in yet) so I dropped to stock. Still ran out. This was after I entered hilly terrain. Makes me cringe when I feel that pedal go dead so I just kept it under 60mph. That uually it only happens at about 85-90 on level 5 or 6 when I'm standing on it. Did my job and started home. This time on stock tune (I haven't tuned my ecm yet), it just hated life. Started dumping smoke out at night. Couldn't tell the color because nobody would stay behind me long enough to see it. It started loping harder than ever, and my dry knock below the ficm just made my fillings want to fall out. I threw a new Baldwin filter on the head and nothing looked odd. At this point, it'll smoke out the street any time I give it light throttle, but the boost looks normal and once I drop the hammer it clears out and goes like an animal.


Oil is right on target with about 5500 miles on it. This morning, it wouldn't start without a sniff. I just put the scanner on it. I focused on fuel pressure and scaled it to 5000psi min/7000 max. It's not a "saw tooth" per say. Maf looks a little high but that's a cold start at about 40 degrees F. I should mention that recently they were out of diesel kleen, so I bought Howes because it runs like crap without that treatment. Might have something to do with it.


Balance rates look good and all within spec. I'm not sure how because they were junky injectors from the start, but it may be returning more than they should. I'll start with bypassing the fuel system and maybe a clear hose on the rail when i have time. I'll clean the maf as well. K&N has some time on it and I probably over oiled it, so that, too. Possibly a weak CP3? I did notice that I was getting upwards of 17-18k psi when I was comanding around 14 or 15k.



This forum is full of ears. It doesn't hurt to ask. Has anyone heard this racket before? Sorry it's blunt, but I knew it would be long. Any helpful advice to speed up my diag time would be awesome.









https://youtu.be/bHozatm8Q8Q

 

[DAVe3283]

Wow, that does not sound happy at all. The truck is having a very hard time regulating fuel pressure. Given what you said about it's history, it's probably a combination of the injectors and FPR both being almost dead.

Can you get a log of the main fuel rate and main pulsewidth at idle?

And if this is the plug-in Edge box, completely remove it from the truck and see if things change. Those older Edge boxes didn't actually have a stock setting, even though they claimed to.

I'd do a return test to try and narrow it down to injectors or CP3 for the no-start. See what you get and go from there.

 

[jlawles2]

As suggested, completely remove the edge.
Check the boost tubes, small holes have been known to get rubbed in the hot side tube by hoses. Small leaks cause issues that the turbo can cover once it gets on top of it.
I would also suggest running a compression test. Might have bent a rod and not realized it. Its a long shot, but a bent rod will cause haze at idle and clean up quite a bit when at speed.
Also if you have access to it, try running a cylinder cut out test. If you have one that is leaking you may be able to find it.

 

[BoominSVX]

I didn't disappear. Just haven't had time. The Duramax comes off the road for winter in the rust belt. I had to finish an excavation job today, run around pulling batteries, draining pressure washers and checking coolant It'll be 16 degrees here tonight. Way early and wrecks me for the wintertime "bumper crop". Also, my 2500hd gas job is having its own fit. My diag is nock sensors so they're on the way with a new harness. I had to snag the wife's 2nd gen Cummins to finish the job.



Anyway, I had the edge on and off. I knew not to trust the edge Delphi connectors and with hptuners hooked up, it was off anyway during testing. The ECM is stock as far as engine, but I did a bit with the trans to help prolong the inevitable. The edge stays on level 6 all the time and only turns down when I have a load on. Usually I wait until I'm at the end of the on-ramp at 60+ and turn it down to prevent that adaptive trans from getting bad habits. I use those up and down buttons quite a bit. It drives me nuts that programmers have gone to pcm write changes in order to make an adjustment.



Sound like I need to get it started again (hopefully) and check some timing numbers. I'll post them if I can do that. I guess it'll just have to be a hypothesis, because I'll never buy a co3 or injectors unless I can prove they''re needed. I'll pressure test for fprv leaks. I know I have a cap that I made for boost leak checks somewhere around here. I'll run a line into a diesel can to rule out everything beyond the rail, and clear hoses. If nothing shows, I'll do the for and shim the fprv at the same time due to location.



Again, no blowby, and I don't see a compressed rod causing a no start condition. Fuel at cranking was only about 1800psi until she started catching. Not to say it's impossible, but much like a boost leak, it wouldn't effect starting. She should still fire on what's left for pistons and would start with no intercooler. The no-start was right along with the smoke issue, and it's been getting progressively longer with crank times. If the for and fprv don't fix it, then it'll be sac 45s because I know I need those. If still a no go, it'll be on to an lbz cp3.



It'll take some time, but I'll update when I find it. There's a video where you can clearly hear the truck. Maybe it'll ring job someone's memory or help someone in the future. Let me see f I can get this thing started on summer fuel with a gentle sniff of no-no juice tomorrow. I'll try to get some timing numbers for you. BTW, mine is the edge CS similar to the CTS but fits in my overhead pod out of sight. Only a year old if that, and fully updated. I'll be pissed when they stop selling them. I won't even leave it in the truck for heavy rain. My cab lights leaked once and I had to swap out my display which was when they told me they were running out of those CS units. To be continued...

 

[jlawles2]

There is also a known issues with the fuel lines collapsing under vacuum.

 

[BoominSVX]

I understand this fact, but again, it still pulls like crazy on hard pedal and there would be less vacuum under starting conditions, which wouldn't explain the no start condition. That may be the reason for the fuel topping out after 80, but the Fass would also take care of that if I can ever find time to drill a hole for the sump. Trying to avoid continuous air bubble entrapment in the fuel which means I need an empty tank, hole saws and through-sump returns. I'm just glad it's not a vp44. You might get 2 chances to run that down on lube before you're buying a new one. I've got alarms on the wife's Cummins now, but it still can't be good for the cp3. I could just cut the line and stuff the fass (or any pump) in temporarily as a diag test, though.

 

[BoominSVX]

I had some time to play with it today. I slid some clear hose on the line from ficm to the filter head. Found bubbles coming through. I push fuel pressure up beyond 20k to shove air out until the hose was clear of bubbles and dropped it back to 5k. They came back. Fuel pressure wouldn't go above 23k psi.



Then I pulled both quick disconnects and stuck my "top end cleaner" hoses on and stuffed them in a jug of diesel. Primed and started. This time, the bubbles left, fuel pressure got up to 24k once or twice but no higher, and bubbles did not come back. Still knocked and fuel pressure was all over.



I decided to start disabling injectors. Hit #6 and she stopped that random knock, but still had the wave on actual rail pressure. Sounded better though.



Something I also noticed. There was a post I saw once that said rail pressure was supposed to be 1-1.8 mpa with key on engine off. If it's not, they recommend to change the rail pressure sensor. Mine was reading 0.2 mpa or 24 psi. Seemed odd, but I'm about to throw in the towel on this because....


At least 1 drivers side injector which means I'll probably kill the other 3, a weak cp3 ( exactly 250054 miles), a bad FPR, possibly a leaking fprv, leak in the fuel line, and I don't doubt for a second that it's not sporting a boost leak by how she's running, but I don't care at this point. The cost of injectors, the lift pump, and a complete lbz cp3 is the cost of another duramax around here. That's not even getting in to the rockers and cab corners and cracked frame crossmember. If I do any more, I'll post it, but this thing has me about spent on patience. The only reason she's still here is because my Chevy's run longer broken than most Fords will run at all, but I'm getting too old for this crap.