TD5 intermitant missing?

sam1986 · Jun 23, 2011

:doh: i have a 53 td5 and rcently it has started missing odd times, fine for days on end then suddenly...a miss/cough, with mil lamp flashing when the miss occurs but then everything goes back to normal. i have had it to a 2 garages, 1 of which is a LR specialist, full diagnostics tests show no fault codes, all earths are fine, injectors are fine, pressures/ampage etc were all checked and are 100%.....im stumped!

sometimes feels a bit flat after the miss, like extra lag or struggling to breathe. MAF or something perhaps? (they said this was running fine too by the way)

any tips greatly appeciated as this **** of a problem is burning a hole in my pocket trying differnt bits n bobs

Cheers lads!!

pos · Jun 23, 2011

It could be a number of things. TD5's have a lot more electrickery / sensors on them than the engines that I'm used to working on, but there are a few pretty standard things you might want to check:

1) Remove all air intake hoses and inspect them internally for any signs of delamination or collapse. If a hose is just starting to collapse, it can be sucked flat before the turbo boosts (i.e. at vacuum), preventing the engine from getting the air it needs.

2) Check for air in your diesel. The tiniest leak along your fuel lines can let air in, but not necessarily leak diesel out. In the case of your TD5, the fuel line is under pressure immediately from the tank, so it could be the in tank pump that is at fault (fractured?). I have had a problem with my 200tdi up until earlier this week, where air was being drawn drawn into the fuel line along a line that is under pressure.

3) You could have a temperamental fuel pressure regulator

4) You could have water in your diesel

5) You could have a clogged fuel sedimenter (if TD5's have them)

6) You could have an injector that is on its way out. It wouldn't necessarily show its self in any engine diagnostics testing either.

I take it that the specialists will have taken a look at your fuel and air filters?

-Tom

Mackenzie · Jun 23, 2011

Hi, mine had a collapsed intercooler hose, looked fine from the outside but not so good inside. new hoses are much stronger and robust. good luck.

mackenzie..

Ampo · Jun 24, 2011

Have you checked the red plug on your ecu for oil? Could be the the old leaking injector loom problem.

sam1986 · Jun 24, 2011

pos said:
It could be a number of things. TD5's have a lot more electrickery / sensors on them than the engines that I'm used to working on, but there are a few pretty standard things you might want to check:

1) Remove all air intake hoses and inspect them internally for any signs of delamination or collapse. If a hose is just starting to collapse, it can be sucked flat before the turbo boosts (i.e. at vacuum), preventing the engine from getting the air it needs.

2) Check for air in your diesel. The tiniest leak along your fuel lines can let air in, but not necessarily leak diesel out. In the case of your TD5, the fuel line is under pressure immediately from the tank, so it could be the in tank pump that is at fault (fractured?). I have had a problem with my 200tdi up until earlier this week, where air was being drawn drawn into the fuel line along a line that is under pressure.

3) You could have a temperamental fuel pressure regulator

4) You could have water in your diesel

5) You could have a clogged fuel sedimenter (if TD5's have them)

6) You could have an injector that is on its way out. It wouldn't necessarily show its self in any engine diagnostics testing either.

I take it that the specialists will have taken a look at your fuel and air filters?

-Tom

hi tom, thanks for the tips,
the specialists ran all injecters and all wer firing as they should no timing issues etc.
tried changing harness as ther was oil in loom but as i hav found out, that wasnt the problem, air and fuel filters are all clear, and just had a new fuel pressure regulator fitted as old one was leaking. any other suggestions lol

cheers

sam

pos · Jun 27, 2011

sam1986 said:
hi tom, thanks for the tips,
the specialists ran all injecters and all wer firing as they should no timing issues etc.
tried changing harness as ther was oil in loom but as i hav found out, that wasnt the problem, air and fuel filters are all clear, and just had a new fuel pressure regulator fitted as old one was leaking. any other suggestions lol

cheers

sam

Sorry it's taken me a while to get back, I've been away all weekend.

It sounds like you have covered a few of the more substantial possibilities, but it will more than likely be something daft, simple and inexpensive. Have you checked your hoses for any signs of internal delimitation or collapse - they are not always the easiest things to spot. Also, if you have had engine oil working its way down the loom, it may be possible that it has already founds its way into the ECU which could cause a number of problems.
Have you tried unplugging the MAF sensor? Does it run any better without it connected?

A typical symptom of the in-tank fuel pump being on its last legs is inadequate pressure, which might explain the flat spot, and it could also create a misfire under certain circumstances if pressure is significantly lower at the head. Does it start easily?

You could also try priming the system just to see if it kicks out any air that might be stuck in the system. There is a technique relating to the ignition and the accelerator pedal although which one it is, I am not sure. Take a look though this: http://www.landyzone.co.uk/lz/f7/help-please-how-do-i-prime-td5-fuel-system-63679.html

There are so many things to try

-Tom

TD5 intermitant missing?

sam1986

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pos

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Mackenzie

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Ampo

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sam1986

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pos

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