zd30 stalling randomly

[Jakeex]

hey guys,
been having a bit of a tricky problem for a few weeks now and can’t find any answers

back story.
so the nav, zd30, used to be my daily but now i have my own business and drive a van for most of my travels. nav sits in the garage on charge and i drive it every few weekends.
been extremely reliable.

drove to my sisters a few weeks ago, (25mins) got there fine, sat for around an hour and when i got back in, it cranked but wouldn’t start. primed it, checked all the fuses but no luck. then 5mins later it just started. took off and it stalled out the driveway. same thing, cranked for a while and then after a minute or two it started.

drove to my in laws place with no issue (20mins) then parked for about an hour again, and wouldn’t start. this time no luck, waited 20mins or so and tried again but just cranked over.
luckily my house is a 10min walk so i went home and a few hours later went back, it started as normal, drove home no worries.

did the obd diagnostic with pins 1 and 8 and found 0407 iirc, crank angle sensor. cleared the code, ordered a new one and while i had time, changed the fuel filter since it was due.

got the new sensor, installed it, went for a drive, maybe 10 mins in, it stalled. jumped out, primed it and it started. then stalled again 10mins later.
did a big block a few times and it was just random, sometimes i’d get home with no problems, sometimes it would stall, sometimes just stutter and keep running. but then the last 2 blocks i drove, i had no problems, so i thought maybe i didn’t prime it enough when i changed the filter and it was just a coincidence. checked again and no codes.

it sat for another week or so, i checked the battery, it was a little low so i thought maybe low voltage was the issue. but then disconnected the alternator, had it idling at 12v and then turned on everything i could and got it down to 11.1v with not even a hiccup.
charged it anyway.

drove back to my sisters place with no problem, sat for a couple hours. on the way home it stalled but it fired straight back up (with the key) while still rolling. did it again in 50m, started it and drove the next 15mins home without a problem.

googled for hours and a few people suggested clear hoses at the primer to check for air (it does sound like air in the fuel to me)
i have the inlet side with only very very small bubbles, basically solid fuel delivery. and the outlet side of the primer is foamy like a kitchen tap, big bubbles randomly etc.

thought that was 100% my issue, so ordered a new primer (non genuine unfortunately) installed it, made sure the filter was all on correctly, but with clear hoses it’s exactly the same.
both primers prime hard though, and with it idling and holding revs at about 2k, even with the bubbling outlet line, it sounds perfectly fine, no stutters, stalling etc.

i haven’t had time to drive it yet with the new primer, but chasing any other ideas on what this could be. really hoping it’s not the injector pump, but with the list of codes i figured if it was, something would show up.

sorry for the long read, but i figured more info is better

thanks for any help in advance!

 

[tweak'e]

a common place for air to be sucked in is the filters bottom o ring. people forget to change them, or install them twisted. check the hose ends, a few people have found them split at the end. also double check its the right filter, i had one wix filters list the wrong one before. same fittings but different filter.

any sign of diesel bug? i wonder if you have got something clogging the pipe down by the tank or even the tank pickup.

 

[Jakeex]

thanks for your reply

never even considered diesel bug, will have a bit of a read into that
thought about pulling and cleaning the tank just as something to do anyway so might have to now.

i’m sure the filter came with a new bottom o ring and i always coat it in diesel before fitting to lubricate it. wondering if the water sensor is letting air in too, but haven’t found much online saying anyone has had issues with them

fuel lines, i’ve replaced the outlet side with another piece of hose as a test, didn’t have enough on me to do both but with clear hoses the inlet side had very little air and the outlet side had a lot, so assuming it’s not a hose causing that

 

[Erick]

The best diagnostic tool for all the problems you have written about is an in-line low pressure pump. Depending where you instal it, you can find out delivery volume (blocked pickup/fuel line), instal before/after filter to create vacuum /positive pressure to check for air leaks, etc. You can run vehicle with pump going or not if fuel delivery system is good.

 

[Jakeex]

hey mate, that sounds very interesting, can you elaborate on this a little? is this something you’ve done?

i’m pretty mechanically minded, i understand how that would be an upgrade but can’t picture how this would work as a diagnostic tool though. like how do you work out what is happening with the pressure, by installing the pump?

is this in conjunction with the clear lines? moving the pump causes air bubbles in different spots, or eliminates air bubbles, etc?

thanks!

 

[Erick]

hey mate, that sounds very interesting, can you elaborate on this a little? is this something you’ve done?

i’m pretty mechanically minded, i understand how that would be an upgrade but can’t picture how this would work as a diagnostic tool though. like how do you work out what is happening with the pressure, by installing the pump?

is this in conjunction with the clear lines? moving the pump causes air bubbles in different spots, or eliminates air bubbles, etc?

thanks!

In reply. Yes I have inline pump permanently installed. Does not have to be operational, I have a seperate switch Since I sorted some problems a couple years ago I have not used it. I got rid of the primer bulb set up and use a generic filter/water seperator.
If and I say if your problem is air in fuel, the inline pump can be used as you suggest to see flow rate ( possible blocked line, etc) or air entering system. The zd30 is pretty basic compared to newer vehicles, the other things I can suggest is check earth points and wires at the three points along intake manifold in particular and the connector/wiring down to the injector pump. Although your experiment with running down the voltage seems to indicate all is well there.
The other thing to check is the duty cycle (IDC) of the pump. Need to go to a Bosch diesel place, but the check is just a plug into your diagnostic port in the cab. As the pump gets older it may be having trouble picking up fuel.
It is possible the injector bleed off line running from front top of cylinder head is leaking. For some reason they run it to the intake banjo on the injector pump. And there is a small filter there as well.

 

[tweak'e]

commonly its the primer, that leaks. or the filter orings. checking the water trap valve is a good idea.
i have a thread on here where i removed the primer, welded a plate on top and used an outboard motor type squeeze bulb back at the tank as the primer.

if you fit a fuel lift pump, if the leak is big enough it may leak and you can find it. a good thing to test, but what often happens is the leak seals itself.

having some fuel pressure on the injection pump is a good idea. there should be a few threads on it.
you would need something like a holley high flow pump, some one way valves as bypasses (in case the fuel pump is off). a way to power the pump and have it shut off in an accident. spill line mod (move the spill line from the ip inlet to the ip outlet).

 

[Jakeex]

once again, appreciate the great replies

i received the new primer, fitted it (still with the clear lines) and the bubbling didn’t change

put the old lines back on, primed it and then gave it one last squeeze and my dad noticed a drop of fuel come out of where the outlet hose meets the solid line on the firewall, so i’ve replaced that hose

driven it maybe 30-40km since and it seems okay, hasn’t stalled or stuttered or anything yet so fingers crossed it was just the primer out that hose. if not, i think my next step will be taking off the fuel line at the tank and pressurising it somehow, to see if there are any leaks, which will tell me if it’s air in the fuel or another issue.

but i will also check the earths on the manifold in the meantime, and start saving for a new turbo cause i think that’s on its way out too haha

thanks again!

 

[Erick]

Fingers crossed, lol. The turbo on zd30 motors is very reliable. Are u running a boost gauge? And an exhaust temp gauge is a good idea. Between the two and a visual inspection around the turbo exit on the impeller side for excessive oil or fine metal dust, u will know everything u need to know.

 

[Jakeex]

Fingers crossed, lol. The turbo on zd30 motors is very reliable. Are u running a boost gauge? And an exhaust temp gauge is a good idea. Between the two and a visual inspection around the turbo exit on the impeller side for excessive oil or fine metal dust, u will know everything u need to know.

well, think it’s fixed the fuel issue. been driving it a fair bit and it hasn’t missed a beat

the turbo starting making a really strange noise when just starting to spool, but it’s stopped now. got a boost gauge but no egt, it’s on the to-do list. i’ll inspect the turbo properly but sounds normal again. currently looking into an intercooler just for a little piece of mind in case the turbo does let go

 

[MichaelT]

well, think it’s fixed the fuel issue. been driving it a fair bit and it hasn’t missed a beat

the turbo starting making a really strange noise when just starting to spool, but it’s stopped now. got a boost gauge but no egt, it’s on the to-do list. i’ll inspect the turbo properly but sounds normal again. currently looking into an intercooler just for a little piece of mind in case the turbo does let go

Oh dear. My turbo was making a scratchy whistle as it started spooling up. I was doing some highway driving the other day and the turbo started sounding scratchy the whole time.
The next thing I knew was I had engine runaway and had to clutch-stall the engine to stop it, as the oil feed to the turbo was going through to the air intake and fueling the engine.
I should have taken the turbo off I suppose and stripped it down, but the scratchy whistle disappeared briefly on mine too (!).

 

[Jakeex]

wellllllllll. back to square one.
been fine for a few weeks, been driving it as much as i can to make sure it’s okay.

loaded up all my camping stuff yesterday ready to leave, then thought i should quickly do an oil change since it’s just about due.
had to go to my parents place to drop off something so just did the oil there, was all good, drove home and then 2 hours later when i went to leave for the weekend, it cranked and didn’t start.

neighbour came over, we got it started with start ya bastard and the accel pedal did nothing at all, didn’t increase revs, didn’t idle, just didn’t want to run, so definitely think it’s not getting fuel. which leads me back to thinking it’s the injector pump.

i’m sure when i get home tomorrow it will start first go, making it super hard to diagnose yet again
but still have to check all the fuses properly, those 3 ground wires, looked okay at a quick glance in the dark but will suss it all out properly.

any other ideas?
any other signs it’s the stupid injector pump, i’ll scan for codes etc but i’m sure it’ll come back clean like before

 

[MichaelT]

the outlet side of the primer is foamy like a kitchen tap

That has got to be your problem - air getting in at the primer/filter assembly.
Has this cleared up??
I'm also wondering - does air rush in to your fuel tank when you remove the filller cap? Navara fuel tank breathers have a reputation for blocking up. The breather sits in a hole in one of the chassis rails.

Have a look at this post too about fuel filter O-ring:
https://www.navaraforum.com/threads/challenge-fuel-issue-run-out-of-ideas-solved.25064/post-281680

 

[Jakeex]

hmmm
i replaced the primer assembly with a new one (non genuine from navarapart, bc genuine is expensive as)

but it didn’t change anything with the outlet looking foamy. so i removed it all, fit it up again making sure all the o rings looked correct, and still the same. but it runs perfectly fine with the outlet line being foamy. idles beautifully, smoothest it’s ever been, i tried loading it up with the handbrake and trying to take off, turbo started to spool so was under a bit of load, line still foamy, didn’t miss a beat.

and then after 2 weeks of driving it decides it doesn’t want to start randomly.

just got home and hopped in it, battery sounded a bit flat obvs from cranking so long on friday, and it fired up straight away, again, idling so bloody good.

can’t even try to diagnose it now because it started, which rules out simple stuff like fuses etc

when i get time i guess i’ll pull the primer assembly off again and check it once more, i’ll check the fuel tank breather i suppose, worth a look, otherwise i can think of anything else besides the stupid inj.pump ecu cracking the ***** when it’s warm sometimes?

 

[MichaelT]

You mentioned fuel pump ECU.
Apparently the wiring harnesses to these can be problematic.
Next time you have a no-start, perhaps try wiggling that harness and see if it comes good.

Discussed here in a fair bit of detail.

 

[tweak'e]

hmmm
i replaced the primer assembly with a new one (non genuine from navarapart, bc genuine is expensive as)

but it didn’t change anything with the outlet looking foamy. so i removed it all, fit it up again making sure all the o rings looked correct, and still the same. but it runs perfectly fine with the outlet line being foamy. idles beautifully, smoothest it’s ever been, i tried loading it up with the handbrake and trying to take off, turbo started to spool so was under a bit of load, line still foamy, didn’t miss a beat.

and then after 2 weeks of driving it decides it doesn’t want to start randomly.

just got home and hopped in it, battery sounded a bit flat obvs from cranking so long on friday, and it fired up straight away, again, idling so bloody good.

can’t even try to diagnose it now because it started, which rules out simple stuff like fuses etc

when i get time i guess i’ll pull the primer assembly off again and check it once more, i’ll check the fuel tank breather i suppose, worth a look, otherwise i can think of anything else besides the stupid inj.pump ecu cracking the ***** when it’s warm sometimes?

first thing is fix the foamy fuel. thats sucking in a lot of air. that can stuff the injection pump.
hoses are known to split at the ends.
check the bottom fuel filter o ring. really common for people to miss that. check the water drain as well.
makes sure you have the right fuel filter and its not clogged up. blocked up filter will cause a ton of vacuum which will suck air past clamps etc.
what can happen is the air builds up, forms and air bubble and air locks the pump and runs the pump dry. especially when its sitting.

 

[Jakeex]

have you done the clear line test yourself? does it look like a solid stream of fuel? cause i read a few things that say there shouldn’t be air bubbles, and i also assumed that, but like, if there’s black fuel lines how would you ever know?
but might have to check the bottom o ring and maybe the water separator, haven’t come across anyone having problems with them though

 

[tweak'e]

have you done the clear line test yourself? does it look like a solid stream of fuel? cause i read a few things that say there shouldn’t be air bubbles, and i also assumed that, but like, if there’s black fuel lines how would you ever know?
but might have to check the bottom o ring and maybe the water separator, haven’t come across anyone having problems with them though

yes. see one of my threads where i took the primer off and welded a plate across it and used a outboard motor type plunger back at the tank.
i had stream of bubbles, but if you left it idle for a while and rev'd it, a big bubble of air would come through.
once fixed its solid fuel, it can't even tell its flowing.

yeah you don't know as you can't see it, thats the downside of suction fuel systems. a lot of diesel engines today have in tank lift pumps and don't have that issue.

 

[Jakeex]

yeah, lift pump seems like a much better idea, at least you’d see a fuel leak

i’ll check the bottom o-ring and tank breather and if neither fix it i guess changing all the rubber fuel lines isn’t a bad idea.

with the clear lines though, i had only reallyyyy tiny bubbles on the inlet side and then a foamy stream on the outlet side, so i’m taking it that suggests a problem at the filter housing yeah?
o-ring or the actual water sensor
filter is the correct part nb, new ryco filter too. maybe the new primer housing is dodgy