Misfiring TD4

Hi all, I've owned my Freelander for over a year now and this forum has been very useful to me but I've only just now become a member! (Left that a bit late).

On the way back from Scotland last summer my 2005 TD4 developed a misfire, loss of power at high speed, erratic idle and cutting out. To fix that me and my mechanic friend have replaced; the in tank pump (and tank cradle cos it was rusty!), Fuel filter, fuel pressure sensor/switch/regulator and cleaned the fuel rail. It then ran great but it took a lot of figuring out.

Now it's developed a similar problem where it jerks and misfires at high speed but under 1500rpm and at idle it runs fine. It's also sometimes very difficult to start. I know it does have a leak from the high pressure pump area but it's had that since I've owned it and it hasn't got much worse. It's on my list to do, it's just quite expensive.

My thoughts are injectors, MAF, throttle sensor, or some electrical fault as it is intermittent. It lost power entirely and wouldn't restart in a Tesco car park the other day but after being on hold with the RAC for 5 minutes I tried the key again and it ran fine ???

Any help will be greatly appreciated. I love the car when she does run but it is getting a bit frustrating. I want to fix some niggly problems like the passenger door lock, faulty power mirrors, air con, and the speakers but I can't while the engine keeps failing every 3 months

Thanks

You really need to get any engine fault codes read which will be a guide. If the engine cur it should have stored something.

However, I have seen same problem and I would go to the high pressure fuel sensor at the battery end of the fuel rail.
Remove the plug connector carefully and inspect with a bright lamp. If it is green and moldy looking there is your problem.
Clean it anyway with switch or contact cleaner.
Hopefully that will solve it. It is, at least, cheap to do. There is also a possibility that you have a duff hp sensor wiring loom but I would try the above first. If you can get the codes read then report back !!

Unossofrus said:

Now it's developed a similar problem where it jerks and misfires at high speed but under 1500rpm and at idle it runs fine. It's also sometimes very difficult to start. I know it does have a leak from the high pressure pump area but it's had that since I've owned it and it hasn't got much worse. It's on my list to do, it's just quite expensive.

Click to expand...

i rekon you need to get that leak fixed .. asap ..
because it also could easily be the cause of those symptoms .. and will only get worse.
[ just saying as i've chased a similar issue in the past
[ whereas the pump could not supply the required pressure on demand
[.. and i had to replace the hp.pump ..
https://www.landyzone.co.uk/land-ro...-plausibility-deviation-at-high-speed.362488/

( edited to add )
be aware that hp.pump seals can fail rather suddenly with little warning.
in which case the engine will cutout and not restart.
also .. sometimes the seal to the crankcase fails .. noted by the oil level increasing .

andyfreelandy said:

You really need to get any engine fault codes read which will be a guide

Click to expand...

+1 to that advise !
..

If it's not starting, that could be the lp pump as well. I understand you haven't changed that one.
Otherwise lack of power I went back from cyclone to the fluffy crank case breather filter and after about 6T miles it went down on power side and increase of fuel heavily. I changed it last week and it improved again but as andyfreelandy said fault codes would be good if any.

Here Crankshaft sensor - check & defective | HELLA

I have a similar problem, my TD4 at idle has a misfire and then usually whikst driving around the 2000rpm mark.

Now ive heard something about a common issue with a 2k misfire and read so many different fixes, had the codes read today and the only one that has shown itself is P1605 Power interuption in KAM.

Searched google for the answer but either my google searches are terrible or there just isnt any info out there on this code and how to fix and also if this is the cause of the misfire.

Had a search round the forums for answers but like i said so many fixes for issues not exactly like mine. Wonder the brains trust here had any ideas. This has now bee going on for a number of years and the vehicle just isnt being used and i hate seeing it sitting there and not getting dirty!

Thanks