ZD30 engine

[solarman216]

Never had a chance to tear down an injector pump, let alone rebuilding a one. Therefore, I do admire(and envy at the same time) the folks who's done it and can do it.

It is not that hard, go to a scrappy and buy one just for the sake of it, and strip it, taking note all the while, Rick

[Rumcajs]

Thank you threedogs, will have a hunt in the UK, interesting thing is after putting it back on the internal tank in order to move it I was surprised how well it ran such that I took it up the road, almost perfect and soo much power, so I am now investigating the pump myself, I might add I am an ex diesel engineer, so am well capable of a complete pump strip and rebuild, but of course I have no calibration equipment now so will only be looking at a simple look for anything that could cause this to happen, on the 2.7 there is a mini filter and a metering orifice, we have found the mini filter is best removed, do not know if the VP44 pump has this or similar but I will find out,

VP44 doesn't have any screen in the inlet side. VP44 injection pump can be stripped on the bench at home but then what? Without calibrating bench and know how it is a rubbish bin after that. Biggest fcuk up is the pump's own ECU controller and its terrible PCB design and cooling implementation. Any fuel starvation will overheat it and after while it renders its joints/contacts unsatisfactory. Epic fail by Bosch designing this abomination, it needs fuel not only for injecting/operating but for lubrication and cooling as well, the reference design is just marginal and car makers don't include extra lift pump even though it is needed badly. See the U-tube about how to test and check the pump ECU at home.

I hope you have re-routed/modified the leak/spill line from injectors in to return fuel line as normally it is connected in to intake line (suction side) on the injection pump so if you pressurise that line from addition of another lift pump guess where else is that fuel going?

One of the reasons why it has run better with added lift pump is also because extra fuel pressure and flow causes hydraulic timing advance mechanism to deliver earlier injection which results in better response. Retard the injection timing and it is lazy/guttless but when you have just enough fuel for injection there is not much left for timing device actuator because the built in lift pump simply struggless especially at lower RPMs.

Cheers

[mudski]

Well explained there mate. The pcb had cooked itself on my pump. as far as im aware, the pcb is not replaceable too. unless im wrong....

[Rumcajs]

Well explained there mate. The pcb had cooked itself on my pump. as far as im aware, the pcb is not replaceable too. unless im wrong....

Well, the whole PCB is encased in silicon like compound which is rather difficult to remove on top off the ribbon cable solder joints etc. Bosch also made sure that it can only be programmed 3x and that's it. You can replace the entire assembly, the ECU+ sensors/actuators but good lack finding them.

[solarman216]

Well here is the latest, cleaned out the fuel tank manually, full of gunk, replaced the rusty metal fuel lines with copper and rubber, replaced the filter and the result stationary is good idle to 4k plus good, and hold at high revs 3k and above also good, no hunting or missing, return to tank has good pressure indicating the lift pump is good, only reason I could not test drive it today was deleted the clutch balance pipe but could not find the blanking disk that I needed, got many but finding is the problem, Rick

[solarman216]

Well will not need to at the mo as motor is performing great, there seems to be a lot of different info regarding this pump much of it conflicting, the IP on this motor has its own lift pump inside and it works well, on top of that Nissan has put the injector leak offs into the feed to the IP now this is under negative pressure so a poor leak of pipe will allow air to enter, but also if a pressure pump was installed to feed the IP this would be very bad for the injectors as they would no longer have a free path to discharge leak off indeed they would have positive pressure obstructing this this may not effect the injectors themselves as their pressure is around 2k psi but the leak of will not be designed for positive pressure at all, Rick

[solarman216]

Sorry again replied before I saw the other posts, so starting again all I have actually done is apply a 60 plus psi neat derv supply for a few minutes from a fuel drum on the ground, when I reconnected the on board tank (in order to move the motor) I expected it to run rough as before but it did not and it has continued to run almost perfect since, and actually took it up the road today and it went like a train, the only small hickup was at lower revs with small throttle, so customer is going to take it as is with the theory that a few blasts up the motorway with a trailer on will sort it, I have just to fit a new exhaust and a few other jobs and he can have it possibly next week end, so why, I can only assume the crap veggie formed a sticky lump someplace that the higher pressure derv shifted?????? Rick

[solarman216]

on another note just won a 3 on Ebay dirt cheap so will have a pump to play with, pick it up tomorrow about 25 miles away collect with the trailer, Rick

[solarman216]

Negate that the Ebayer put it up as a by it now but for bits, now who is going to pay £150 for say a wing mirror?????, anyway got a needed bonnet for £50 other than that took the motor up the road and all seems good, time will tell, Rick (must say i find it hard to navigate this site, b ut that is probably because I am long in the tooth and used to our one)

[solarman216]

Well the latest update to this issue, customer collected yesterday eve and drove it the 100 odd miles home and reported no issues at all, pulling like a train, so sorted with a high pressure boost for a short time to the IP plus new filter and fuel lines and proper derv, Rick