TD42 misfire ?

[coddawgz]

Hi all, so I've recently bought my first patrol 89 model GQ TD42. Motor has a slight misfire (best way to describe it) just as it reaches around 1500rpm.
It starts great and idles beautifully. I'm not the too cluey on diesel motors in depth but I know the basics. It doesn't appear to have a diesel leak.
no sign of and damage to the injector lines or pump. Has a new head fitted to it as the previous owner rebuilt the top end (so he says).
New core plugs in block so i'd say someone has done some work to it. I am suspicious of the valves/ rockers for damage or not adjusted correctly but it has no
unusual Ticking or Clacking sounds.

There is also a wire that I have come upon which seems to be quite thick and is live when the ignition is ON. Sits on the front corner of the intake manifold and follows
back into a fuse box/wiring cluster ?
Unsure of where it goes as it is quite short. I know a workshop manual would most likely help me but I haven't got one as of yet.
I have booked in the Patrol at my local diesel specialists (Cairns Diesel service) for Monday but I thought i'd try my luck here first !

So here are some pics of the wire that is doing my head in !

Cheers and sorry for the novel..
pics are sideways also -__-

[BigRAWesty]

I'd say the fuel pump is out. Either to advanced or retarded.

[nissannewby]

Timing won't effect it like that.

Check the inlet to the injector pump. There is sometimes a small gauze filter in the inlet which can get blocked and cause what you have described. If it's in there then there will be a small spring on top of it and the filter is underneath it. You will need a small o ring pick or a small bit of wire to fish the filter out.

As for the thick wire this is for the glow plugs and should turn off after a short while.

[coddawgz]

Hey guys cheers for the replies.
I failed to mention that I've already checked the banjo filter and found there wasn't one in there ... as for the wire cheers mate !
If I rev it slowly from idle it doesn't misfire at all. I'm a little Suspicious of a fuel delivery problem due to it only happening when I punch it in the guts.

[nissannewby]

Yeah it's happening when you are asking for full load. When was the fuel and air filters changed last?

Also what condition are the rubber hoses in the engine bay?

One thing to try which is beneficial regardless of pump condition is to fit a electric lift pump like the carter 4600hp. If the electric lift pump fixes the issue then it's a good sign the pump is getting worn.

[coddawgz]

Well I just bough the car but the filters could do with a replacing, not dirty just old. The hoses throughout the engine bay are ok.
Oh yeah so that's just like a turbo for the fuel pump ? its ticked over 600,000k's so I wouldn't be surprised if the pump is on it's way out. could've been replaced who knows.

[Bigcol]

I would try the fuel filter first, and if it is still doing it - then go for the elect pump.........

I had that problem (miss firing, coughing and spluttering (at over 2500rmp) no one could find the problem, until we changed the fuel filter (it was only 3 month old at the time) all of a sudden, all good..........

[taslucas]

I'm definitely not the one to ask about diesels but maybe Injectors getting old?

[Clunk]

Hi all, so I've recently bought my first patrol 89 model GQ TD42. Motor has a slight misfire (best way to describe it) just as it reaches around 1500rpm.
It starts great and idles beautifully. I'm not the too cluey on diesel motors in depth but I know the basics. It doesn't appear to have a diesel leak.
no sign of and damage to the injector lines or pump. Has a new head fitted to it as the previous owner rebuilt the top end (so he says).
New core plugs in block so i'd say someone has done some work to it. I am suspicious of the valves/ rockers for damage or not adjusted correctly but it has no
unusual Ticking or Clacking sounds.

There is also a wire that I have come upon which seems to be quite thick and is live when the ignition is ON. Sits on the front corner of the intake manifold and follows
back into a fuse box/wiring cluster ?
Unsure of where it goes as it is quite short. I know a workshop manual would most likely help me but I haven't got one as of yet.
I have booked in the Patrol at my local diesel specialists (Cairns Diesel service) for Monday but I thought i'd try my luck here first !

So here are some pics of the wire that is doing my head in !

Cheers and sorry for the novel..
pics are sideways also -__-

The only thick cable that I have going from the manifold, goes to an earth point just below battery, then on to the negative battery post. I do have a thick lead that goes to the front glow plug rail though but don't remember where it comes from.

As Bigcol said, I'd be changing the fuel filter first and see what happens. I had a similar issue a few months back, where if I was trying to accelerate or go up a long hill, it would lose power and what I could only describe as feeling like a misfire (being relatively new to diesels myself). Would be absolutely fine, while at idle or slow acceleration. Anyway, replaced the fuel filter and haven't had a problem since.

Would loose glow plugs also cause this sort of problem?

[Avo]

Hey guys cheers for the replies.
I failed to mention that I've already checked the banjo filter and found there wasn't one in there ... as for the wire cheers mate !
If I rev it slowly from idle it doesn't misfire at all. I'm a little Suspicious of a fuel delivery problem due to it only happening when I punch it in the guts.

when checking for the filter in the banjo fitting mate..did you take it off and in the hole in the injector pump right down the bottom of that is where the little filter sits..i know you said you have looked but I had the same problem..it's right douwn in the hole of the injector pump..use a tooth pick to dig it out..it has a brass top...get a torch and look in there as you cannot see it only the brass top..hope that helps

[Bigcol]

when checking for the filter in the banjo fitting mate..did you take it off and in the hole in the injector pump right down the bottom of that is where the little filter sits..i know you said you have looked but I had the same problem..it's right douwn in the hole of the injector pump..use a tooth pick to dig it out..it has a brass top...get a torch and look in there as you cannot see it only the brass top..hope that helps


not all TD42's have that gauze "thimble" in the pump........

but you are right, I used a safety pin, bent the last 3mm with pliers at 90* and got it out that way - was a bastard to try and see............

[Gutsquisher Media]

There is also a wire that I have come upon which seems to be quite thick and is live when the ignition is ON. Sits on the front corner of the intake manifold and follows
back into a fuse box/wiring cluster ?
Unsure of where it goes as it is quite short.

This wire is for the glow plugs, it connects to the first glow plug in line the power is then feed though the flat plate that is attached to all the other glow plugs.

The misfire could be a air leak in the fuel line, as the fuel line is not pressurised as the air can be sucked into the line as engine load increases. This would possibly the source of your diesel leak.