Slightly down on power when warm?

Hi guys, a few of you might remember me from my original thread where i was asking about which EGR i should get. Since then i've been asking around a lurking on the forum often...

So after i removed the EGR, clean Maf and Map sensors, and a few other tweaks, the guy at the garage thought he noticed the wate gate sticking...a good few doses of wd40 and it was all sorted...and now it pulls like a train, especially when the turbo kicks in, the power surge is phenomenal...

I still have a nagging problem/feeling though. It feels like after a few minutes of fun driving, as soon as the engine has warmed, it no longer feels as snappy. When the engine is cold, on 2nd gear as soon as the turbo kicks in, the surge is felt. When the engine is warm, the power comes slowly on 2nd gear. There is no surge the way there is when the engine is cold. The engine is much down on power, it just lacks its snappy feel.

Am i just paranoid or is this possible? Maybe some kind of thermal protection or something like that? Or is this completely normal? Engine isnt remapped.

what about oil in the ecu's red plug? ... or at the upper plug where it connects to the injector loom? ...if there is oil there put a new injector harness: www.discovery2.co.uk / Workshop /Injector Harness if that's ok remove the viscous fan and drive it so to see if there is some difference cos when the engine warms up the viscous coupling of the fan locks and it puts some load on the engine... but this doesnt have to make a very big difference, just that it feels a bit

Harness has been changed fairly recently so there shouldn't be any oil. Though I'll double check. What about the fan? I'm assuming its not an easy job to remove it right?

If there is a slight difference in the power when the fan warms up, then that just might be what I'm feeling. The change I feel is quite small and is especially felt at lower revs.

I doubt you'd feel when the fan locks up as its a viscous hub unit that gets progressively stiffer with temperature.

Its easy to remove. Just get a spanner that fits and give it a tap anti clockwise as you stand in front of the engine to loosen it. Then carefully unscrew until it comes off. Slide a piece of cardboard or hardboard down between the fan and the radiator to protect the fins.

The ecu will cut power if it is overheating. What vehicle do you have have defender or disco?

It's a defender. Yes i would have thoughtnit would cutout. But would the cutout be evident, like a full limp mode, or would it start toning the performance down to keep things ok?

There are quite a few sensors that come back from the engine to the Engine ECU, there are only Two that will stop it when the engine is running, the one that stop the engine are 1/ Earth feed back to main relay and if the main relay goes out then so does your fuel pump relay, all other sensors if faulty the ecu goes back to factory set perimeters, So the engine when hot may develop a faulty sensor return feed to the Engine ECU and then it will reset its self to the lower prest settings that are factory set, So get your self an OBE2 reader and see what reads as faulty.

Could it all be a question of how warm/hot the engine is and the warmth of the air going into the engine?

i.e. when the engine gets warmer, if the exhaust gas temperatures get hotter, does that in turn cause the air going into the engine to be warmed up by the heat in turbo, thus less compressible and thus it gets a less efficient burn? The intercooler is obviously there to cool the air down, but if the air going into the intercooler is warmer/hot , then by default it's going to go out warmer then when the engine was cold...

I've had 2 Td5s that pulled better cold than warm. Always assumed it was an air temp thing - cold air=denser=more oxygen...?

That's what I think too ...

My Td5 had a stuck thermostat, regular operating temp was about 95-98 degrees, though a normal Td5 should be 86-88. New thermostat and the temps dropped to normal and the engine had a lot more power. This could be your issue. The temp gauge on the td5 is useless, shows the same if it's 100 or 86. A nanocom will let you know if you're running hot. I would guess what sabredylan said is true of the ECU -- it would make sense that it cuts power if the temps are rising.

It doesn't really cut power by much, it just feels heavier. When it's cold, it feels like a happy young puppy, all raring to go. When it warms up it feels, mmm, less sprightly.

Yeah, heard about the gauge. Once it warms up, it stays in the same place. Only goes up if it hits very bad temps, only happened once to me when the belt broke. (Didn't give it time to overheat though)

Ain't got a nanocom to be able to read the temps damn it :|

This exactly what mine is doing I have replaced the injection loom also but when is really warm I'm still getting some residual oil in the red connector only noticeable when I inject the carb cleaner into the red conector a little black oil comes out but getting better.