when working with the machine and using pressure, engine RPM go down, and can stall the engine. It does this on every thing, driving, digging, even when I change the bucket. It’s getting better with higher rpm but still useless. There is no error codes I noticed after stalling the engine and it runs back up in rpm, black exhaust. Tells me there’s a mechanical problem and not a electrical cut off from the ecm, or? There was a problem with a sensor in one of the blocks sensor nr 4 in the split picture. It was error code 40 transmission pressure failure. Ordered a new sensor and the code vent a way. What I have done so far. *checked for debris in both filter in hydraulic tank. Both fine no debris or metallic flakes * changed both filters in hydraulic tank * changed all filters on the fuel and engine system * no strange sounds from the hydraulic system * engine has no problem sounds god and responds great *all controllers works great inside the machine Sorry for my language, I live in Norway All help and thoughts will be appreciated ❤️
View attachment IMG_1970.jpeg
Ok, that's a little engine. Before going any further. You said, heavy black smoke. That's an indicator to me, that she's overfueling trying to spool up. Do we have a boost leak? Is the turbo broken? She can still throttle up and work without boost, but as you load her down, she can't keep up. Let's also verify air cleaners are not plugged up, no birds nest, bees nest or plastic bags stuck up in there. Not really concerned with fuel at this point, no hard starts, or starvation concerns mentioned. Let's investigate the easy stuff first.
Yes it last for 2-3 seconds before she’s stable back in rpm after it has been stalled. Engine sounds great to me. All filters are new and air system is cleared and clean. What I think is if the ecu holds it back there wouldn’t com any exhaust, but if the hydraulic pump holds it it would have unused fuel. Just a thought
It's simple enough. Just place a gauge on the intake somewhere and see if you ever have positive pressure, if it remains negative or 0 then you have no boost. Do you ever hear it spool up? Do you hear any rushing air?
No I can’t say that I have heard any turbo sound, and I haven’t heard any turbo leaks neither Broken turbo, shouldn’t it have black smoke unused fuel when you throttle up or load the engine. I can check the turbo tomorrow. But the system chokes the engine on idle to, when I try to open up the lock for the bucket I’m not sure what it’s called in English
When disconnecting the bucket, you curl your bucket cylinder over relief, again raising hydraulic pressure increasing the load on the engine. A clean break of a turbo will idle, throttle up and maybe even work hydraulics until the load increases. That's where the turbo, with increased exhaust flow ramps up and pushes air into the intake. I'm thinking, the lack of boost, is contributing to your lack of horsepower. Good luck with testing.
Thanks for your time and answers. I’ll check the turbo tomorrow. And I’ll measure the pressure in the intake manifold. I’ll update asap I have looked into it. Thanks again for your help
Turbo is ok, not the best but delivers pressure positive to the manifold. Talked to Volvo today. They talked about the main pressure valve on the hydraulic pump. I have no idea where it is located or/if it is the problem
View attachment IMG_2078.jpeg View attachment IMG_2075.jpeg View attachment IMG_2074.jpeg
The likely causes of your complaint are 1- Someone has meddled with the max displacement limiter on the pump. Least likely 2- The pump proportional solenoid has an issue and does not limit the pump output under demanding conditions. More likely 3- you have an engine power issue. Most likely You have not stated if this is a new issue or if it has always been this way. You do not include what boost pressure you get from the turbo under full load. Remember this is a load sense system so hold a function at its limit like you would on a hp control machine does not produce full load on the engine.
Thanks again. Do you know if there is a regulator on the diesel pump? Yes we are looking into to lean fueling now and the main regulator on the hydraulic pump This has been a problem since 2016 when the previous owner had the problem over the night and never solved it
If you have black smoke it is generally an issue with over fueling or lack of air. The concept of lean or rich pertains to mixture and is not used when discussing diesel engines. It would be properly called under or over fueling. If it were due to pump over load the engine would typically stall. What boost pressure do you have under load?????
Solved. Broken circuitboard. Main pump was chocked by the rugulator return valve.