Monday, Dec 22, 2008 at 11:52
Another possibility - I had something similar in a 2.5 TD Triton.
Theres a wastegate control lever actuated by vacuum in the manifiold I think... it will look like a small baked bean tin with a metal rod going down to the turbo and a couple small vacuum tubes running in and out of it.
This thing has a rubber diafragm inside of it and when the vacuum increases too high it will open the wastegate on the turbo to avoid overboost.
What happens is with heat and age the rubber diagragm perishes and splits, and this allows the engine to overboost - it fels like your engine has gotten a heap more power...out of no where.
Now there sould also be an overboost releief valve somewhere, mines in the inlet manifold, ad when the wastegate control valve is perforated - the extra boost is dumped via this spring loaded pressure relife valve!
When it is operating - you hear a weird vibrating noise from under the bonnet...it soulds just like the old wood hot
water heater pressure blow off valve...it sorta vibrates in a frequency like a loud humming noise.
Sometimes even oil will come out this boost pressure reliefe valve if you have pressure blow bye your rings.
So - how to test for this simple & easily rectifyable problem?
Usually it is easy to disconnect the straw thin black rubber hose where it enters your fuel pump, and suck on the end of it andwatch the connector rod that goes from the bottom of the small baked beans can down tothe turbo wastegate, and seeif the rod moves up and down as you suck & release the vacuum.
If it does - then the diafragm isnpt perforated and you have some other problem.
If theres no vacuum when you suck and you get air - and the rod connecting to the turbo wastegate doesn't move - then you need to replace that baked bean can turbo waste
gate control can...due to perforated rubber diafragm.
Happened to the bitsamissing Triton at a simlar age / mileage to your vehicle by the sounds of it.
Ohh and by the way - you do that sucking test on the thin rubber hose - with the engine turned off!
When done just plug the hose back onto it's nipple on the fuel pump, and re secure the pressure clamp with pliers or a screw driver if you have the utilux screw clamp type.
God luck let us know if thats what you find.
Cheers
AnswerID:
340866