Gu TD42t hard to start help needed

[johnsy]

Hi guys the patient is a 2000 Gu Ute fitted with the td42t, she was always hard to start and has now completely failed to run after much cranking. I have; checked the glow circuit, replaced glow plugs (just to be sure) had the injectors overhauled, run a compression test (cold), checked the fuel cut solenoid (listened for click in and out) and generally pulled my hair out.

What I'm chasing to start with is a compression pressure for this engine, I was using the spec out of both a max ellery manual and a gregorys manual (for a gq) and both told me 2954kPa to a minimum of 2454Kpa or so. my lowest pressure is 3500kPa and the highest 3800kPa, so i'm wondering if there's a different spec for the early turbos?

Next off the boost was wound up by the previous owner to 14psi, i'm curious does anyone normally advance or retard the timing to go with this increase in boost pressure?

lastly some info about the doctor (myself) i'm a qualified diesel fitter (but only in my first year out) and my background has more to do with heavy mining equipment than cars and as such i've had little to with these older style rotary pumps but have studied the basic theory whilst at tech.

Thanks in advance for your help here guys its much appreciated Johnsy

[300WinMag]

Have you cracked a injector line open to see if you are getting fuel to the injectors?
Check basics like filters, fuel and air, oil preasure cut out switch.

Give us some more symtoms etc.

[a-dog]

hi mate
my 99 gu td42t had a very similar starting issue. would always take alot of cranks to fire hot or cold. Checked everyhing you have mentioned with no luck. Finally checked pump timing and that turned out to be the problem.
pump was too retard (.5 on the dial indicater) Set the pump timing to .65 (i think they factory setting is .62). As soon as i did that it would fire straight up like it should.
It may not be the problem but might be worth checking.

My Nissan workshop manual gives the same specs as you mentioned.

Dont know if many people advance the timing when they increase boost, but i know some people advance it when they upgrade turbos.

[nabstud]

It could also be an air leak in the fuel line between tank and pump. Check/tighten all fittings.

[johnsy]

Winmag I'va also just serviced the vehicle (all oils and filters) whilst replacing the clutch and fixing some other niggles. It was also blowing puffs of white smoke at regular intervals at idle.

Thanks a-dog I've gotta timing gauge set on order and since I know none of this vehicles history I may aswell check her timing, should mention we've already been through and adjusted the tappets.

After more rooting around with the turbo crossover pipe off i think that nabstud may have it, the issue clears up when you constantly pump the primer and the engine is running, sorry should insert here that after bleeding she did start and idle. I have since also adjusted the idle speed and a/c idle speed as both were low.

Also to be entered for history and claritys sake is that this vehicle isn't mine, it's my little brothers and that my N/A GQ never had the hide to play up on me like this haha. I did treat her a little nicer though.

Would be still good to hear if anyone has a different pressure for the turbos compared to the non turbos as I'm a little iffy as to why you would have higher pressure on a turbo as opposed to n/a? I've also done a compression check with the turbo crossover pipe off and the pressures remain the same.

Would also be great if one of the turbo application guru's who lurk about the place could tell me wether standard timing is right or wether it should be retarded or advanced? I would have assumed retarded if anything.

Thanks for the help so far lads we're getting there. Johnsy

[johnsy]

Another quick update... I have replaced the rubber hose from the clean side of the fuel filter to the pump and reprimed and everything seems to be okay at this stage, i'm not entirely sure how it will go starting after sitting for a while as we're yet to source a new alternator for the big girl (did I mention the love this ute gets).

It's still blowing puffs of smoke, but it's now distinctly blue and produced mainly about 1200rpm coming off idle so I'm guessing towards valve stem seals but thats another job for another day since I've still got an AU falcon to get roadworthy. Ah the joys of being off work injured.

Johnsy

[300WinMag]

Sounds like you are getting ontop of it, I am lying in a recliner recovering from injury aswell, double hernia op, cannt think straight with all the drugs they have me on.

[johnsy]

That doesn't sound much like fun at all winmag... atleast I've only got myself to blame. Compression fracture to my L1 vertibrae after taking a fall from the dirt squirter, been parked up for ten weeks now and they're still recomending another four off. The morphine hit was quite memorable though haha.

Take it easy Johnsy.

[300WinMag]

Have you tried playing with the timing by ear so to speak.

[RIZZO]

could also be a cracked head, 4.2 are strong motors but have seen this with cracked heads, not starting, white smoke,

[4wheelinls1]

The advance mechanism in the pump wears and they need more timing to compensate, I power time them on the dyno, I have seen EGT's lower by 50-80 degrees with the correct (optimum) pump timing and more power/economy along with starting better. The puffs of white are unburned fuel, it would missfire at the same time.

Cheers

Joel

[jemmos]

x2 on what joel said. hey joel, alex jones did mine and its 1000 times better, thanks 4 teaching him that!!! and thanks for sorting my intercooler b4 i left to the desert, i heard they were pricks to deal with. thanks!!!