Td5 power loss when warm

ive had my td5 a few months now and when I first got it power delivery etc was faultless but not long after I got it it developed a fault that I haven’t been able to trace....I’ve googled it and trawled through hundreds of pages and since joining yesterday I have tried to find the answer on this forum but so far no luck...when it’s cold the truck runs lovely boost is between 1200 to 2200rpms ish....when the engine temp gauge reaches half way it goes flat no power what so ever untill 2000rpm and then it feels like all the boost lol....I have done a sh*t load to it which I will list but I really am confused...I may add that all this turbo stuff was new to me until a mate explained everything yesterday lol....anyway here we go
I’ve cleaned the injector plug under rocker that goes to red connector on ecu
I’ve cleaned the map sensor
I’ve cleaned the maf sensor
I’ve cleaned the aap sensor
I’ve dismantled the actuator arm checked it’s all free and cleaned and greased accordingly
Checked all intercooler hoses
Had a new intercooler
Bypassed the actuator solenoid (no difference so plumbed bk in)
Checked vacuum hoses
Checked all clamps are tight
Mr muscle cleaned the turbo
Disconnected various sensors one at a time and tried driving it but can’t seem to find a fault
Now I’m thinking the maf could be faulty but not quite dead or I’m leaning towards and temp sensor somewhere giving a dicky signal when it gets warm...coolant? Fuel? I don’t know and it’s doing my nut...any tips hints or pointers would be greatly appreciated thanks

Offer cake and tea for someone local with a nanocom to come round and check for fault codes.

If no diagnostics available, change temp sensor on engine as there cheap, if no better you really need data looking at.

cotney05 said:

I’ve cleaned the injector plug under rocker that goes to red connector on ecu

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Did you check and clean the plug at the ECU end as well?

Hi all and thanks for the replies....yes I did clean the red plug at ecu too....my obd2 reader doesn’t read it so will have to ask see if anyone has one of them nanocom doo daas lol...if I unplug the temp sensor would that fix the issue same as if you disconnect a faulty maf....just to fault find like....I have a brand new temp sensor for a jeep Cherokee 2.5 crd I’m going to see if the numbers match if not will go parts store this morning

Hi, no way to properly diagnose a Td5 this way without a dedicated tester, the only sensor which can be ruled out by unplugging it is the MAF, to rule out other sensors a live data log is needed, as the symptom appears when the engine warms up the coolant temp and fuel temp values are important cos the ECU reduces fuelling on high ECT or FT inputs while the temp gauge stays at the middle up tp 119*C so it can be high temp in reality not a sensor fault, the fuel cooler has a thermostat in it as well which can be ruled out only by watching the live data

Thanks for that...the jeep temp sensor doesn’t fit the plug on my Land Rover which I kind of guessed...I hadn’t actually considered that there may actually be an issue causing it to get hot as you say but only saying half way on the gauge...I guess I need to find a nanocom

cotney05 said:

but only saying half way on the gauge

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Half way on the gauge means between 70 - 119*C and if let's say the thermostat in the fuel cooler is stuck the FT gets equal or even higher than the ECT . There is a table in the fuel map according to which as the FT increases the ECU limits the max amount of fuel which can be injected. From 50 to 70* its limited to 43cc. At 71 degrees it drops to 41cc then drops with every degree increase that's why some of the ''brilliant" power boxes advertised to give more power are working on the FT sensor input by reducing it. The Td5's engine management is quite complex and when such temperature dependant symptom occurs it needs proper diagnose

I have just chucked in £7 temp sensor and mr muscled the exhaust side of the turbo let’s see if that’s helped

Changed the temp sensor and still no joy ....seems I need to fork out for a diagnostic code reader....truly doing my head in now...I know when it comes down to it it’s only going to be something simple too...Sod’s law...also discovered part of my fan shroud is missing ....is it needed or can I get away with out it?

You deffinitely need the fan's cowl, this can be the root of your problem.... do you have aircon?

Yes I do have air con....which sort of works lol....I have made a shroud from the side of my old fridge to test whether that gives me a few less degrees on the temp gauge and hopefully curing my issue....I’m still on the train of thought that the issue is heat related...I may well be wrong lol

And is the aircon fan working?

Yes...it wasn’t it wasn’t siezed as they all are so I got a generic 12v fan soldered on landrover plug and attached with cable ties lol

that fan has a double purpose, beside the aircon it's there to help engine cooling when the coolant temperature goes above 105*C, a generic 80 -100W cheap fan from ebay is not up to the job at all, not even for aircon... the original one is a 250W high flow fan much more powerfull than those generic ones... this corroborated with the missing cowl and eventually a not well locking viscous fan can cause the problem you have as i explained in post #8 .... though what ever it is if you just keep throwing in cheap parts in the vehicle and using mr muscle rather than doing a proper diagnose dont expect it to perform well

I can’t afford a diagnostic of my own and don’t know anyone with one ....my code reader doesn’t read my crappy td5....£6.79 coolant temp sensor cost me and mr muscle is great as a turbo/egr/waste gate cleaner....as for fan shroud I only noticed this morning on anothe td5s pics I had something missing obviously I have seen the 4 bolt holes with nothing in but thought nothing of it....and the front fan was a cheap fix got it £20 brand new vs £40 for a second hand original one that was 40 miles away and may of only lasted ten minutes....the weather so far this year has only made that front fan kick in once maybe twice....never comes on otherwise ...I do have a manual over ride switch so I can turn that on as I require also....I’ve tried turning it on when the power loss occurs but it makes no difference....I’m determined to fix her and all comment and pointers are greatly received but from what I’ve read online and stuff this seems to be a common fault that is hard to trace even with a diagnostic....I’ve read also about resistances and stuff to test components with my multi meter but sadly I don’t know how to use it that good lmao

Resistance checks are futile for this symptom, the only straight route to the problem is to see the live data when it happens, replace the FT sensor in the FPR with the coolant temp sensor you removed for test, as for nanocom owners, there are many in UK willing to help, zoom in on the map https://www.google.com/maps/d/viewer?ll=52.714115530805024,-3.944091796875&hl=en&oe=UTF8&msa=0&z=7&ie=UTF8&mid=1PmbphOvO47RAsn1ZdQFDD-ed-zo to contact one if it is close you have to register to http://www.thed2boysclub.co.uk/index.php and send PM

Thanks for the tips I will check that link...so is the temp sensor in the fuel pressure regulator that simple to sort ...I thought that required buying a whole unit...mint if not again thanks for the pointers you really are helping a lot

Found replacement shrouds on eBay for £15 upwards so looking at a new one of them going to change that temp sensor in fuel pressure regulator since I can get them for £6.79 from local parts store and you recommend I buy a replacement air con fan? Cheers

Yes, a proper fan is necessary, they are expensive but if you dont find good used one you can buy only the motor which fits perfectly to the original blade and housing, the cheapest is to get it from here https://www.rockauto.com/en/parts/vdo,PM9093,radiator+fan+motor,2164