slight misfire 1500 rpm td5

Hi ive only just noticed I seem to have a slight misfire around 1500 rpm its worse from cold but when warm it is still there, I have replaced tge following in the last 2 weeks.
Genuine MAF sensor
Fuel filter
Both oil filters and oil castrol magnatex
Egr bypass
Injector harness (2 months ago) red plug bone dry
Performance air filter

Now having never owned one before to me it seems to go quite well only running problems I can recognise is when in traffic its a bit of a pig to drive stop starting seems to have a flat spot or erratic throttle response ive checked for fuel leaks all seems to be ok wsstegate is free im not sure what elee to check ive had it clagged up to a comp it did bring up egr stuck and mass air low but that was before removing the egr and replacing the maf, ive also removed and cleaned the map sensor as it was coked up.

I forgot to mention it ticks over sweet the rpm needle doesnt even twitch.

How is your fuel pump? I would remove it and check both filters are clean, sounds like a fuel delivery issue.

Injector washers and o rings

Try replacing waste gate control vale.
Land Rover Discovery TD5 Turbo Waste Gate Control Valve | eBay

Thanks for the suggestions, just to be a bit more specific I mean for all I know it could be characteristics of the 5 pot engine, there is no smell of fuel in the oil so dont suspect seals in injectors and there doesnt seem to be a loss of power throughout the rpm range hence why ive not changed the wastegate modulator once it warms up you can hardly feel the lumpyness/misfire from inside the car but you can defo see and feel it whilst under the bonnet its at its worst about 1500 rpm but not like when a 4 cyl drops down to 3 cyl the power is there? And like I said when stuck in traffic its a pig to drive smooth slow because the revs pause then jump up . Hope I make sense, I wish I knew someone with a td5 so I could compare, im just trying to get it in tip top shape ready for my jollys down devon

no1smytho said:

Thanks for the suggestions, just to be a bit more specific I mean for all I know it could be characteristics of the 5 pot engine, there is no smell of fuel in the oil so dont suspect seals in injectors and there doesnt seem to be a loss of power throughout the rpm range hence why ive not changed the wastegate modulator once it warms up you can hardly feel the lumpyness/misfire from inside the car but you can defo see and feel it whilst under the bonnet its at its worst about 1500 rpm but not like when a 4 cyl drops down to 3 cyl the power is there? And like I said when stuck in traffic its a pig to drive smooth slow because the revs pause then jump up . Hope I make sense, I wish I knew someone with a td5 so I could compare, im just trying to get it in tip top shape ready for my jollys down devon

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What you MIGHT be experiencing is the well-known lack of low-end torque, below 200rpm.

However I would still be taking the in-tank fuel pump out and check/clean the gauze filter in the bottom. If nothing else it will tell you if you have an injector seal problem round the corner, as all the black gunge which collects in this filter is caused combustion emissions leaking past the injector seals into the leak back gallery.


Have fun on your jollys,


Dave

no1smytho said:

Thanks for the suggestions, just to be a bit more specific I mean for all I know it could be characteristics of the 5 pot engine, there is no smell of fuel in the oil so dont suspect seals in injectors and there doesnt seem to be a loss of power throughout the rpm range hence why ive not changed the wastegate modulator once it warms up you can hardly feel the lumpyness/misfire from inside the car but you can defo see and feel it whilst under the bonnet its at its worst about 1500 rpm but not like when a 4 cyl drops down to 3 cyl the power is there? And like I said when stuck in traffic its a pig to drive smooth slow because the revs pause then jump up . Hope I make sense, I wish I knew someone with a td5 so I could compare, im just trying to get it in tip top shape ready for my jollys down devon

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Have you plugged in hawkeye/nanocom see if any faults logged.if you put your location there maybe someone nearby with a td5 to compare.

Its been on testbook and only faults were maf n egr

Do I need to drop the tank to access the pump, I had it into simmonites they had a listen and confirmed a slight misfire or lumpy running

no1smytho said:

Do I need to drop the tank to access the pump, I had it into simmonites they had a listen and confirmed a slight misfire or lumpy running

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You get at the in-tank pump via an access hatch under the bot carpet.

Cheers the pump is clear the slight misfire can only be felt on light throttle put the boot down its off like a train checked wiring over air con pump not sure what else to try

oil in ecu red plug mine ran like a bitch mising now and then cleaned plug and loom run great again .

New loom already red plug bone dry

Don't know if it helps, but I cleaned the MAP sensor on my dad's TD5 and it has transformed it. No more misfire under load.