zd30 stalling while driving

[rash]

Hi, new to the forum, and just picked up my first turbo diesel about a week ago. 2003 DX Navara dual cab.
Runs really well, but a couple of times it has stalled while in 5th gear going down hill..... Seems to be when I back off the throttle completely coasting down hill, it cuts out and I don't realize until I go to power on again. Tacho still reads revs as I go down through gears to an eventual stop. so is unwilling to roll start the whole time. pretty sure no dash lights come on until clutch is in and tacho is at zero revs.
Engine will not start again unless I turn ignition completely off and then I can start it again like nothing happened.

I have searched on here a fair bit and found a couple of others describing exactly the same thing. but I have not found a fix...

is it true than the computer turns off the fuel pump while slowing down under compression? maybe this is it and the coputer is not repowering the pump when needed.
With this in mind, I have set up a switch with direct battery power to the pump for next time it happens. if it cuts again, I will hit the swith to see if it will roll start instantly.
Anyone found a cause for this problem?
Thanks,
Ash

 

[tweak'e]

With this in mind, I have set up a switch with direct battery power to the pump for next time it happens. if it cuts again, I will hit the swith to see if it will roll start instantly.

how have you done that ?

these are not like the old VE pumps where you could do that. the ecu sends data to the pump rather then turn it on/off with voltage.

if you have tapped into the fuel solenoid you will fry it.

 

[rash]

a diesel fitter mate of mine checked the wires to the pump with ignition on to find one running same as battery voltage. said I should be able to hotwire it across to the battery to see if it fixed the problem..

 

[tweak'e]

Runs really well, but a couple of times it has stalled while in 5th gear going down hill.....

had someone with that once but never really worked out what it was. unfortunately the person was not very helpful and i have no idea on the outcome.

one thing i have heard of is the injection pump ecu (the one in the injection pump) had a part which tend to fail.
but i would start with the cheap basics before doing that.

one thing you can do is put a decent scanner on it and read the ICV% value at idle.
this should give some idea if pump has other issues.

check the fuel lines and filter. make sure there is no loose lines and filter is replaced.
check for air being sucked into the fuel line. (clear fuel hose on IP outlet)

check vac hoses are ok. nothing like ball bearings in them to block them.
check all fuses are ok.
check earths on the engine manifold.
check battery is ok and terminals are ok.

 

[rash]

was a little suss on battery when I picked it up. its a bit sluggish to start when cold, winds a bit slower for 5-10 seconds before starting. fires up instantly when warm.

 

[tweak'e]

a diesel fitter mate of mine checked the wires to the pump with ignition on to find one running same as battery voltage. said I should be able to hotwire it across to the battery to see if it fixed the problem..

found it in the manual.

the line, which i think is red, runs from ecu relay to injection pump.
if the switch works then its ecm relay fault.
it also powers the ecu so i doubt its the problem but i have seen weird stuff happen.

also the other thing is to once the engine is warmed up let it sit and idle for 10 minutes. this makes it relearn the throttle.

 

[rash]

will run through your list to see if anything helps, thanks heaps.

A bit of searching found that Nissan was recalling cars around that vintage for a relay that caused cars to stall while driving...not sure if related

 

[rash]

found it in the manual.

the line, which i think is red, runs from ecu relay to injection pump.
if the switch works then its ecm relay fault.
it also powers the ecu so i doubt its the problem but i have seen weird stuff happen.

also the other thing is to once the engine is warmed up let it sit and idle for 10 minutes. this makes it relearn the throttle.

yep, it is the red wire.
could be something to do with the ecu relay as the ignition has to be shut down completely and then back on to start.
will also try the tps reset tomorrow also. thanks again!