ZD30T - runs and drives fine, but won't start?

[mistareno]

G'day,
First post here but have searched the forum and not found a similar scenario.

My Brother in law has a D22 with a ZD30T. A few weeks back, the orange check engine light came on. That apparently indicates either water in the filter or an engine fault.

The car was still running ok at that point. When he reached his destination, he undid the drain cog but accidentally removed it completely. He put it back in and tried to bleed the fuel using the primer pump. The primer was apparently a bit dodgy beforehand and wouldn't pump hard.

He couldn't get it going, so it got looked at by a mechanic who got it running after tow starting it. It ran okay for an hour or so but then stalled in traffic and wouldn't restart.

He had the primer pump replaced (apparently it came up as faulty when plugged into a diagnostic computer. I'm not sure how it flashes a fault as it only has a water sensor).

Anyway, the primer pump now pumps up quite well but the engine wont start.

The odd thing is that if you squirt a small amount of 'start ya bastard' it starts and runs fine. You can drive it and it behaves quite normally until it tries to idle. It will occasionally idle (if let down very gently) but it usually just stalls and then won't restart.

I have bled all the injectors and they seem to be consistent in their affect on the engine speed.

The car will idle with the 'warm' switch activatex at the high rpm setting but will not start without a squirt of SYB.

I have checked all the fuses and terminals and earths but to no avail. It doesn't appear to have any vacuum or boost leaks, and it blows no smoke when driving.

I have also tried disconnecting the battery to reset things. It almost seems as though the ecu is not getting the correct engine speed and is not allowing fuel to flow when cranking or <750rpm.

I have yet to run a clear hose between the primer and the injector pump to check for air bubbles, but the hoses and clamps appear ok.

Any ideas? I'm a petrol mechanic so I am stumped.

Hope someone can shed some light.

Regards,

Richard

 

[tweak'e]

put it on a code scanner and check what the ICV% reading is.

i suspect that due the engine being turned over so much with no fuel in the pump, its damaged the pump.
you could try fitting an electric lift pump to apply fuel pressure and see if it starts. if its starts with the lift pump but not without it its probably the timer control valve in the injection pump is leaking and loosing pressure. extra pressure from the lift pump enables it to work.

double check the glow plugs have voltage.

 

[mistareno]

Thanks. The glow plugs definitely have voltage. The pump wouldn't have cranked too much without fuel, but it did take quite a while to bleed through the injectors the first time so I suppose it's possible. I don't know how much it was cranked by the BIL before I had a look at it. The battery was flat, so perhaps alot...
Would a damaged pump cause poor running at other times?
Can the electric lift pump be a permanent mod, or just a test mod?
Should it be after the filter?

 

[tweak'e]

lift pump can be permanent as long as it flows enough, not excessive pressure and you reroute the spill line from the pump inlet to the pump outlet.
i prefer before the filter as filters are prone to leaks and will suck in air. with pump before filter any leaks will leak fuel and be easily found.
some info on this site but tons on http://www.patrol4x4.com/forum/

injection pump could have been damaged when it was originally pull started.

i've had to do a in the field filter change and used compressed air to pressurize the fuel tank to push fuel up.
i have lift pump on the other 4wd and its so easy. filter change and hit the lift pump button and it fills up in seconds.

last minute thought, did anyone replace the o ring on the water tap on the fuel filter?
they probably reused the existing one. sometimes you can get it where they won't leak with fuel but will allow air to be sucked in.

pay to check for bubbles in the fuel line.
i have had it myself when a poor fuel connection caused air to be sucked in and it kept cutting out at idle.

the other thing that can cause no starts but engine runs ok is faulty starter motor or other electric devices (relays etc) causing interference which upsets the crank sensor.

 

[mistareno]

I did ask about the o-ring on the drain cog, but got a blank look from my BIL so I assumed not.

He replaced the filtet and did say the filter came with an o-ring for the sensor. I didnt have a suitable clear hose on the day, so I degreased the area around the pump and aftet a 10k drive it was still dry, but an air leak under vacuum may not leak outwards.

I think I'll fit a clear hose, prime and bleed it again, and go from there.

After speaking to my BIL before, it does sound like he cranked it a bit, so pump damage is perhaps more than possible.

Also, what does ICV% refer to? Its not a term I'm familiar with in petrol world.

 

[tweak'e]

ICV% i'm not 100% sure on but from what i gather its the pulse time of the timing solenoid. not sure if its a correction value or actual. generally measure at idle and low is bad. patrol forum has details on it.

filters don't come with drain o ring. but do come with one for the bottom part. often people don't bother changing them.

 

[Rumpig]

ICV% at idle is normally around 42%, down in the lower 30s or less normally becomes a problem. You could try a Throttle Position Sensor reset too, which can fix poor idle speed, once running and warmed up leave it to idle for 10 minutes (if it will ) this rests the TPS.