Hitachi EX150-5 excavator bogging down

[Knuckleduster]

Started a new thread off after a lot of greaf trying to identifying the machine . It was supposed to be a Zaxis 160LC but after help from Diesel Dave found ID plate on ECU which said EX150-5. Now have correct manual and am stumped.
When machine is warmed up it will bog down and stall the engine. Been through the fuel system inc fitting new primer pump and had to mod the pipes because primer and outlet in wrong position. New supply hose from tank,new fuel filter,water seperator cleaned out. Tank drained and clag cleaned out.
Pump sensors checked for 5v and good earth and as far as I can see all have an output varying with what load put on it. Haven`t taken out speed sensor on pump to see if the end is clagged up with swarf, which would affect the output signal similar to abs sensors playing silly Bs in cars.Found 2 odd relays in hydraulic compartment strapped to the stepper motor whci look like an unoficial mod feeding the solenoid? valves electrics situated in the far left corner of the compartment. One relay just a ball of rust so fitted 2 new ones today and refitted them back into the abs box cable tied to the stepper motor.
A new throttle cable was fitted a while ago so engine learning redone today incase its lost it. Found gasket from turbo pipe to manifold no good ,so replaced. Checked turbo over today, didn`t find leaks but as machine hot didn`t pull hoses off and take a good look at turbo. Turbo on this machine has no control, no actuator etc, so just runs flat out depending on exhaust output. Was going to try machine without turbo outlet pipe connected to see any difference but as usual blasted rain started chucking down, so abandoned effort and swore at machine, walked off in disgust. Any thought any one. seriously thinking about driving this machine into canal and sinking it forever--its got me so hacked off. Need it to use a air operated piling hammer to install steel pilings to stop the leaks. Got a small JCB that I could use but it hasn`t got the reach of this badly behaved crawler.
All modes affected, boom out,boom in,curl bucket,track forward or bacwards,swing left,swing right.
Only thing that seems to work is the auto idle,e mode drops engine revs,hp mode increases revs but all fall down when machine commanded to do anything other than sitting there and running its engine.

 

[Knuckleduster]

Haven`t been about for a while --long covid hit again and floored me so have had to rest up and get strength back.
Machine now has had a session on Dr Dx and given a clean bill of health--so back to basics--ran machine for 3 hours at half engine speed and it behaved itself--tracked it up the field out of the mud, dug a hole in farmers field and filled it in --scraped the area using the wide bucket to flatten out the work area. But as soon as I increased the engine speed the machine would play up. Went back to basics, opened up the tank drain and after poking the hole had a load of crap come our and the diesel looked like secondhand brake fluid and not clean diesel.Decision made to rip the fuel system down again, We found a leaf rolled up nicely in one of the banjo unions, hence machine would work at half speed and not in HP mode or any increase of engine revs. Tank now drained and almost out of machine--going to blast it with a pressure washer to get rid of anything in the bottom of the tank and inspect it with a boroscope. We had allready darained the tank out previously and flushed it out with clean diesel but this time we found a hard crud on the bottom of the tank that seemed to be letting go at times when the machine was sucking fuel. Got some paint that I used on my boat tank and if needed will paint the bottom of the tank internally to coat the steel and stop the possibility of the tank getting crap attaching itself to the steel again. Did this on my 33yr old narrowboat with its inbuilt diesel tanks and have had no further problems--going back to machine on Tuesday next so hopefully will have a solution
Gerry