Zd30 injection pump Bosch VP44

So little while ago my injector pump decided no more in moree nsw about 4500ks from home. Now this pump was only 12 months and 1 day old. A few phone calls I got a replacement from United fuel injection but still cost me $900 for tow (moree to coffs harbor) another $250 at least in gaskets and tools to do the job. So few days later the big rig was running again and didn't miss a beat for the next 7-8000ks home. This got me researching and I found that this pump is very common on Cummins 6cylinder. 6 you say that can't be! Well it is, these are a module style pump. Just change the back end and program and you have it. Now why are ours so common to fail? From what I can see every other model that uses this pump has an electronic feed pumps supplying around 12-16 psi that held in doing 2 things.
1- less stress in the pump trying to pull the fuel from the tank through the filter by supplying it under pressure.
2- cools the pump these are a flooded pump and use the diesel to cool it by supplying more fuel than is required it bypasses the pressure relief valve and cools the pump.

Now this is just theory. I haven't had a chance to try it on mine yet as I'm looking for a suitable pump. I'll be moving my main filter to under the Ute near the tank with the pump and running a 2 micron filter up front.
Thought I'd put this out there and see what you guys think. Let me know!

this sounds very plausable, was talking to a diesel mech that does heaps of these and he did say the biggedt killer is heat on the electronic module on the pump!

cheers
bryan

The electronics failing due to heat cycling on the VP44 is well known. The Navara would be one of very few fuel injected cars that doesn't have a lift pump which is just stupid. I fitted a lift pump to mine with an inline filter pre pump.
http://www.bluechipdiesel.com/vp44_diagnostics.html
http://www.turbodieselregister.com/threads/227489-VP44-Fix
http://www.remmington.info/testproceed.html
http://dodgeram.org/tech/dsl/ISB/Vp44.htm
http://articles.mopar1973man.com/2n...m/88-bosch-vp44-injection-pump-overflow-valve
http://www.cumminsforum.com/forum/98-5-02-powertrain/1043370-source-vp44-electronics-re-work-3.html- see post 30.
http://www.frenchcarforum.co.uk/forum/viewtopic.php?f=7&t=42962
Apparently Bosch don't recommend a duty cycle higher than 50% or the pump suffers from a lack of cooling/ lubrication, which is why the high powered ones in the States fail alot.

Merredin Nissan said:

Now this is just theory. I haven't had a chance to try it on mine yet as I'm looking for a suitable pump. I'll be moving my main filter to under the Ute near the tank with the pump and running a 2 micron filter up front.
Thought I'd put this out there and see what you guys think. Let me know!

Click to expand...

theres a few setups on patrol forum.
someone did an intank setup which is nice and quiet.
some have carter pumps which can be a bit noisy. i think one problem they have is the built in regulator valve wears quickly.
holley, noisy as.
carter carotor, lower flow but fairly quiet. i have one on the toyo.
facet, only one model as barely enough flow (similar to carotor)
airdog or fass is an interesting one.

one catch with 2mic filter, finer you go the less it flows. pay to use stock one up front and put a 100mic before the lift pump.

I'm thinking Carter as I've got one on my tonner and its good. Yes you may have less flow with a 2 micron but with a positive pressure feeding it it's going to be better off. Thinking of making kits depending on how they work.

the increase pressure will not over come the drop in flow rate due to the filter. there can be a big flow difference between the various mic filters.
you can get bigger 2mic filters that will have the right flow rate, fitting one in might be a challenge.

16psi 100 gallon hour pump should do it. But it's also surface area on it as well it not like it's a little filter. They are made bigger with more surface area creating less pressure/flow loss.
It's still better than no lift pump and 5 meters of fuel lines.

Merredin Nissan said:

16psi 100 gallon hour pump should do it.

Click to expand...

overkill and would need additional regulator. don't go by the cummins setup. they are a little bit different.
ours are made to suck fuel up from the tank. internal regulators in the vp44 ip will be set for that. adding a small amount of pressure (4-6psi) won't hurt anything. 15psi + could well upset the IP internal pressures.
a lot of the guys tend to go for the 72 gph range. but tuning shops have been fitting 30-40gph pumps which i personally think is a little to small.
some have tested a few and found fuel pressure drops fairly quickly and goes into vac as the rpm rises. its still less vac than no lift pump, but i would prefer some pressure at all times.

16 psi max and 100 free flow gallons. If I suck through the original filter and force it into the 2 micron and mount the pump up front I should be ok I'll put a gauges in when I do it as I'm doing boost as well. Just waiting to see if a friend can mod the tune parameters in the stock ecu so I can lean out the mid to top end more

Merredin Nissan said:

16 psi max and 100 free flow gallons. If I suck through the original filter and force it into the 2 micron and mount the pump up front I should be ok I'll put a gauges in when I do it as I'm doing boost as well.

Click to expand...

16psi is to much. you need a regulator. holley do a bypass regulator. fit that after the pump before the 2mic filter and it should pump fuel through the stock filter constantly which will 'polish' the fuel.

Just waiting to see if a friend can mod the tune parameters in the stock ecu so I can lean out the mid to top end more

Click to expand...

why would anyone want to do that ??
most are trying to put more fuel in !
leaning it out will just make it slow. besides the cheaper easier way to lean it out is to keep the foot off the throttle !

To right, the drivers wish is as flat as a pancake as it is.

Well found interesting facts on these pumps. Flow out of the return line at 400rpm is 80-90lph. 3000rpm sees about 180-200lph! Bigger return line will help cool it. 2mic filter is a no no will NOT flow enough. Standard filter is fine pump can handle it just not water. 2 stroke oil is recommended. So all I'm doing now is ditching 3 meters or unnecessary fuel lines relocate std filter and larger return line. Maybe larger feed line to primer pump.

bigger return line won't do much. it won't increase flow through the pump.
best thing to help cool it is to do spill line mod which moves spill line connection from pump inlet to pump outlet. also a trans/oil cooler on the return line can help reduce heat.

fitting a bigger inlet line would reduce the pressure drop at the pump. but fitting a lift pump is far more effective.

When I spoke to Bailey's diesels vp44 guru he said adding pressure to the pump will do more damage than good. I'm changing my fuel lines due to damage that has happened some time in its life so the feed line will become the return line then I'll put a larger line for the suction side.

Merredin Nissan said:

When I spoke to Bailey's diesels vp44 guru he said adding pressure to the pump will do more damage than good.

Click to expand...

im interesting to find what would get damaged and how.
or is it a fob off "manufacture knows best" routine.

I'm changing my fuel lines due to damage that has happened some time in its life so the feed line will become the return line then I'll put a larger line for the suction side.

Click to expand...

bigger inlet will certainly help. you can change the inlet fitting to

Not sure. it could put to much pressure on the pump seals ands fill the motor with diesel.

we are only talking 4psi or so. yanks have 15psi in stock form as some of there have factory fitted lift pumps. a little bit of pressure won't do any harm.

i think the big problem with vp44 is the timer piston housing gets a little scored from rubbish in the fuel. this leaks a little bit and drops the pressure required to do correct timing. typically the drop in pressure is at low rpm's. a lift pump would help a lot with that as it tends to have the pressure at low rpm.

great post- fuel cooler heay hmmmmm

Found this on the Patrol forum, seems the vp44 earned it's reputation. https://www.youtube.com/watch?v=HtA9_A1fHTk

I feel like you just stole 10 mins of my life.....laughed tho.