GU 1998 TD42T rough idle and smoke

[Clunk]

G'day mate, welcome aboard

[threedogs]

Hello ansd welcome to the forum, enjoy

[Roland the Wolf]

Hi ALL, sorry for the delay in responding. Too busy. Just updating as to where I am at with my issue.
Had all injector serviced with new seats and pintails. Made a big difference to my problem but the rough idle and white smoke at cold start-up is not 100% cured, much better though.
With the Patrol stationary and bonnet up, I find the engine misses at revs 1500 to 2500rpm. Now when I disconnect the fuel "in" to the filter and connect a fuel tin suspended from the bonnet, thereby gravity feeding into the filter, I have NO more misses at the mentioned revs. My thought is that the injection pump is starving for fuel. Installing a pre-delivery pump could fix the problem but this may upset the internal workings of the injection pump.
I am open to suggestions before I delve head over heel into this issue.
Have not replaced the hand-pump at this point. I have a definite air pocket in the filter, i.e. fuel draining back to the tank. After a 24 hrs stand, before I start the engine I can pump about 4 hand-pumps before the air pocket appears to be filled.
Staring is fairly instant.
Another point I found is, when I rev the engine to say 2000rpm and let the throttle come back to idle position, the idle revs slowly drop back so far that after some 20 secs the engine will stall, but, but, if I then press the hand-pump 1-2 times before it stalls, , the engine comes back to normal idle .
Your thought, opinions and ideas would be appreciated.
Thanks in advance,
Roland the WOLF 17/8/2015

[Nightjar]

Have you checked the filter under the inlet banjo to the fuel pump?

[MEGOMONSTER]

Welcome mate, surely the best forum on the net.
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[Roland the Wolf]

Hi ALL, thanks Nightjar for you efforts with the pics. YES, I was aware of the filter at the injection-pump fuel "IN". I actually fitted a new one and kept the old one as a spare. The original filter was ok and only had minor small bits collected.
Ordered a new Hand-pump assy. Will let you all know when I replace same and what difference if any it will make to my beast. Keeping my fingers crossed. I am eventually aiming to pull a 2Ton plus van around Australia and I will not leave until I am confident with the TD42T.
Now whilst I think of it, for you Gurus out there, is there any mod I can do to improve the TD42T performance. The only mod I have is a 3" exhaust on my TD42T. Im thinking intercooler. Is it worth considering. Im confident that I could fit it myself. Any other worthwhile mod ?
Thanks for your interest.
Roland the WOLF 18/8/2015

[Roland the Wolf]

Oh one more thing. I would like to check the timing of the VE pump with the jig and dial gauge. Seeking brief instruction. I know that I have to remove the high pressure lines to the injectors from the VE pump and remove the bolt in the centre of the VE hi Press pump head, and then somehow the timing jig is fitted to the hi pressure pump head. and that the bit I don't yet get. Going by the manual on CD which I happen to have. I can do the forward and backward movement of the crank with ref to TDC. Just do not know how the dial gauge is fitted to the pump head. Any hits would be great, thankyou.
Roland the WOLF 18/8/2015

[Cuppa]

After reading through this thread my ‘diagnosis from afar’ is either the lift pump, which the replacement you have ordered will fix if that is the problem, or the line between the fuel tank & filter has a small leak..... hard to see, but letting in sufficient air for the line to drain back into the tank overnight. Sucking in air would also account for the miss you have observed. To be honest changing the line would have been the cheapest first line option & IMHO therefore the first thing to try.

Another way folk have dealt with not holding prime is to fit a one way valve into the fuel line. Our Nissan Civilian bus had one of these when I bought it, not sure why as once removed (as part of a fault finding exercise to find the source of air in fuel - giving symptoms of loss of power & heaps of white smoke) it held prime ok ..... AND gained another 10kph - turned out the one way valve was too small & restricting fuel flow at higher revs. (It turned out that the air getting in was the result of an intermittently sticking exhaust valve).

[Bigcol]

not sure what Turbo you have fitted - 1998 they were all N/A (Naturally Aspirated)
so if it has a Turbo - it is maybe after market
it will depend on how much Boost it is making as well

if you are quite handy, mechanically, have a look for a Factory Turbo & Intercooler from the wreckers, you dont want the Turbo, but the factory Intercooler with the brackets etc will be a shed load cheaper than a Cross Country Intercooler

it will help "cool" the air from the turbo (making it denser) helping to lower your EGT (Engine Gas Temperatures) going out the exhaust
lower temps, more efficiency, more power

[Roland the Wolf]

Hi to you Cuppa & Bigcol. Thanks so much for your replies. What a great forum. Cuppa, I actually removed the Lift-pump blocked off the filter "IN" and connected a vacuum pump with gauge to the filter "OUT". Noted that the vacuum slowly leaked away. Hence my suspicion re the lift-pump. Interesting though your mentioning of the fuel line from tank to filter. Definitely no leaks visible. I have looked suspiciously at the rubber hoses attached to either end of the tank-to-filter fuel line, but as I said NO visible leaks. Have also thought of the one-way valve, but I often consider the fact that if the manufacturer did not fit it, hence it should not be required.
So if the lift-pump does not cure my problem, I will have to give the fuel line closer attention. Shall see.
Bigcol, yes, well it looks like a factory turbo, all appears to look very original. Now Im learning here Bigcol, is the BOOST, the pressure out from the turbo into the manifold ? I assume so. I take it, the EGT is the exhaust gas temp at the exhaust manifold. I hear some 4x4 people have a BOOST,EGT and other gauges fitted to enable monitoring what the turbo does. I think that sounds like a good idea, if I fitted some gauges to my beast. What are some necessary readings to keep monitoring. I commonly hear BOOST reading and exhaust temperature. Can you give me leg-up here, as to where the gauges are connected to get the various readings.
Now re the intercooler, I take your suggestion on board, thank you. There are different types of intercoolers are there not? Which one is the better? If Im going to go to the trouble of fitting one, I may as well fit a gem.
Anyhow, thanks again for all of your interests and assistance with my dilemma.
Will keep you all posted with my progress.
Roland the WOLF 19/8/2015