high egts in top gear only (auto D2 td5)

[Toppa]

just back from a 10hr drive and towards the end i lost a heap of power and my egts went into the hi 600s until i backed off the throttle. This was down hill also! I basically drove home in 3rd for an hour as it seemed to stay a lot lower on the egts. i had my nano evo hooked up and the eng temp was reading ok, mostly about the low to mid 90's. but so to was the boost pressure - 0.65 at best, normally 1.2bar. mind you it was 40+ deg c today and im towing a heavy camper trailer. i also heard a noisy fan sound that got worse during heavy acceleration. initial inspection of the turbo didnt sbow hp anything unusual like gaskets or missing hoses, bolts etc.

thoughts?

boost modulator?
wastegate stuck open?
delimitation of turbohose?

[slug_burner]

Delamination of turbo hose sounds a possibility. Not unusual for the EGTs to drop in a lower gear, you are trying to push out more torque in the higher gear which means more fuel and more boost both wich generate heat.

Not enough boost means less air and if you are pushing a higher gear the fuel demand will be there, more air helps with cooling the exhaust gases so I would not rule out any faults with the turbo or control or cooling of the intake.

600C is not tragic for your engine but you don't want it much higher for long periods of time, that is if you are taking yor temp reading pre turbo.

[Toppa]

cheers slug, yep temp pre turbo. Madman set to alarm at 680 and stsrted going of on a down hill slope, i knew something wasnt right. pergaps the fsn noise i could hear wss the air trying to squeeze through the restricted hose? possible. ill rip it off tomorrow and have a squiz. cheers

[Toppa]

no smoke out the rear though come to think about it, so it might not be delamination, but still going to check.

[Disco Muppet]

Check to see if you've not got a hose slightly slipped off.

[Timmy]

The fan noise is very likely your viscous fan because it was toasty outside. The hotter the fluid in the fan coupling, the tighter it binds as it tries to suck heat out of the radiator. Will take some power out, I'd say 5%.

My car was doing it all today too, completely normal.

Sent from my HTC_0P6B using AULRO mobile app

[Toppa]

it wasnt the viscous fan, i know that one from previous experience, but thanks for the suggestion though, always appreciated.

it was definitely coming from the turbo area, very distinctive and followed the turbo spooling.

[Blknight.aus]

Quick and dirty.

Boost is the engine trying to make power EGT I'd the engine trying. To make torque

Top gear requires the same. Amount of power at lower rpms so there for needs more torque so higher egts.

Initially this starts to add. Heat load to the cooling system once the cool I g system heats up the viscous fan hooks up more so adds more load to the engine, more load needs more torque....

[Toppa]

Thank Mr Knight, explains it perfectly.

Found the culprit.......

blown hose
8913089131

temporarily fixed with my magic liquid till i can order a replacement. Not sure if will hold for long though

89132

[Fluids]

Time for a set of silicon turbo hoses me thinks ...

[Toppa]

i think so as well, might even do the egr while im there.... be rude not to;-)

[Toppa]

funny thing now ive replaced the hose with an oem one..... it now overboosts heaps, well any time i acellarate a little hard, not foot to the floor just normal quick acceleration. I ve wound the boost back a fair wack without any change (made the rod longer)

when removing the old hose assy, i did take off the small hose that goes to the modulator but nothing else. im still seeing 1.2 + of boost on the nanocom.

im not to sure where to go from here? ill check to make sure i didnt dislodged something, but ither than that im out of ideas. :(

[slug_burner]

What do you think the hose to the modulator you say you removed does? Could this be the cause? Or did you mention this as a temporary measure while performing your replacement of the damaged hose?

[Toppa]

hey slug, had a look this morning and found the other end of that hose had come off the modulator.... problem solved. i must have pulled it harder than i thought when removing the other end.

cheers