My machine is a 2019 cat 299d2 xhp SN DX205061, was running and started throwing the low rail pressure leak code and would go into limp mode and then finally stopped running and will crank but not start, will start on ether but immediately throws the leak code and shuts down once ether dissipates. Replace filter and lift pump and i am getting fuel up to the high pressure pump no blockages. I'm not diesel mechanic but have hooked it up to cat et and shows no active codes. I'm assuming it's the hpfp but it's an expensive guess, so i wanted to get some opinions. The numbers in the picture are while cranking the engine. Am i on the right track with the fuel pump or could it be the rail?
With access to ET you're obviously far better equipped than most. Let's take a few steps backwards to start with. What, if anything, has been done to the rest of the fuel supply system so far apart from the filter & pump.? By that I am referring to tank, lines & fittings (esp. the elbows in/out of the filter head shown below), screens, etc. In particular there is an inline screen between the tank and the transfer pump. Circled red - It lives just below the pump.
That is all that was changed after the machine quit. Ive got good flow in and out of the filter/lift pump with no leaks. My filter system is different than the diagram (the picture was before i replaced pump and filter)
You replaced entire filter head with pump, correct? Could the relief valve, #10, be dumping the supply fuel pressure? Are all lines in correct place?
As for blaming pump, there is diagnostic link in here. 2015 cat 299d2 523613-5 pressure relief valve line current below normal Machine goes into low power mode, turn off and turn back on and it runs fine for few minutes and then code pops back up. can’t find anything online on this, any help? HeavyEquipmentForums
I did not replace the entire filter head, I took one line off at a time and blew air through to check for blockages and placed them back on and secured them. It will only throw the fuel leakage code when it fires on ether otherwise no start no codes
Well, it's your machine, but, I've had to road call and replace that pump only to find the inlet restricted, and/or the cavity between the inlet and the filter. Twice on no start. Once on no prime. 3 times on poor performance under load. Get a hold of a fuel pressure gauge and measure supply pressure from filter assembly to high pressure pump. 30 psi gauge is sufficient. If at least 5 psi, then attach gauge to hose circled below, from engine side, and retry. That's the dump hose for the rail relief valve. It should remain zero when cranking. Yes, you may have a bad high pressure pump, but these tests will help confirm it.
Ok thanks I'll do that tomorrow, I'm a small business so trying to do what I can myself before I call in the big money! I appreciate the help
Back to my earlier post. Don't lose sight of the fact that those injection systems hate fuel contamination with a passion. On a machine this size the fuel tank can easily be a source of water and/or dirt. When was the last time the drain plug was opened to check.? The drain plug is underneath, either on the LH rear corner of the machine or behind a hatch roughly in the centre of the engine compartment. As HMC says, at the end of the day the HP pump may have suffered a hernia, but if it was a result of contamination and the issue has not been addressed then it would pay you to investigate all potential sources and make sure they are clean to prevent the replacement going the same way. Just my 2c, YMMV. P.S. You never confirmed if you had checked the relief valve as mentioned by HMC in Post #4 above.
Cat shows these two being bought together. #1 and #3...both pointed out above as places to pinch and test/ try.
Sorry it's been a busy weekend but I got back to it today, i removed the filter head assembly and cleaned every thing, I'm getting good pressure before the relief valve I circled in blue but only getting 1 psi past that. I pulled the relief valve out of the fuel tank and it is dumping fuel out of the valve. I tried to bypass the valve with a fuel line straight to hpfp inlet and still not getting fuel to start. As I mentioned I'm not a mechanic I just know enough to sometimes get by.
I'm also getting a 0 psi reading while cranking on the dump hose for rail relief valve
The rail relief should always test 0 ZERO.
Priming pump output, deadheaded, should reach a minimum of 7psi.
Injector return flows? IF you have good fuel supply, ^ 7 psi ^, at the HPCR pump, and no flow at rail relief, its either the Hpcr pump, or injectors. My experience has been injectors over pump 10 to 1, but I'm not sure you could leak enough fuel through injectors to drop cranking rail pressure to 38 psi. Thoughts from the Cat guys?
Right, I just wanted to mention that I checked it and that it in fact was at zero. I am getting around 12-14 psi on the prime pump output, the fuel is dumping back into the tank at the tee relief valve, I'm going to order a new valve, will bypassing that valve work temporarily to get fuel to hpfp
I wouldn't, that little plastic tee is a pressure reducing valve. Drops pressure from your transfer pump from 10ish psi to 1-2 psi. That's all the HPFP needs to work properly. If you can't confirm you're getting that 1-2 psi then replace it. It's worth it since it gets expensive from here on.
Update, hpfp had a catastrophic failure according to the mechanics pump rebuild guy, no clue why or how but now I've got to pull the rail and injectors. It will cost more to have it rebuilt than a brand new pump but it will come with a warranty, what would yall recommend?
Depends how catastrophic. If there's bits of fuel pump missing, or very high wear, then there will almost certainly be damage to downstream components due to the stupid high pressures these things work at, and I can't imagine there NOT being any damage to the seat area of the fuel rail discharge valve. I'm thinking a Cat dealer would only warrant this repair if 4 x injectors, fuel rail and HPFP were replaced with new. If you've found someone with enough know-how to disassemble, clean & reassemble the injectors then that might be ok. Keep in mind there's a trim file programed into the engine ECM for each injector, so any small changes within an injector (caused by replacing parts or abrassive cleaning) could cause you issues. I would've thought a new HPFP would've come with more warranty than a rebuilt one?! If the new pump is genuine, then sure. I wouldn't be comfortable installing a cheap-ass HPFP. Cat probably understand this too and price them accordingly. That's tough luck. Either way don't forget to calibrate the pump control solenoid with ET when the new/rebuilt pump get's installed and put the injectors back in the same holes they came from. And remember these pumps are timed to the engine. Good luck!