200Tdi seems a little sluggish

In message , Alex writes

Possibly fuel starvation. Check filter and also water trap if there is one on RR.

Could be diaphragm gone in injector pump. This detects turbo pressure and provides more fuel. Ensure pipe from turbo is OK, not punctured or split.

Check for any splits in air hoses from turbo to intercooler although they usually cause a whistle.

could even be a slightly low turbo pressure this post makes for a spot of light reading

Reading some of this coupled with Hughs comments above is lending me to suspect there may be a problem somewhere in the wastegate to diaphram area of things. I am thinking that I will intercept the line from the turbo to the injector pump and fit a pressure gauge, at least I can see if the turbo is actually producing any boost. Do I actually have to get it running along the road to see, or should the boost cut in the same when the engine not under load?

Alex

It'll only produce boost under load.

Check there are no exhaust manifold blows while you're at it. I'm being persecuted by the bleedin' things at the the moment and it pretty much kills boost pressure.

Er, not quite. The engine doesn't have to be under load but does need spinning up. It'll produce more than enough pressure at rest if you take off the hose and put your hand over the turbo outlet. Rev the engine and there should be a fair bit of pressure on your hand, similar, oddly, to an exhaust pipe pressure.

TonyB

FFS if you don't understand the workings of something please at least STFU rather than disseminate misinformation to people looking for help. To check for a turbocharger problem you need to check for maximum boost which can only be done under load - free revving will not produce any significant amount of boost.

On or around Fri, 15 Jun 2007 22:35:03 +0100, "Pete M" enlightened us thusly:

must produce some pressure at high revs off-load, though? might not be full boost, I admit. But at (say) 3000 rpm, the engine is pumping 3000 x 1.25 litres per minute of air through the turbo impeller, and that must be generating airflow in the compressor.

Now, if you had a very clever turbo it could idle when not needed, and only generate boost when the engine is under load, and this would probably be more efficient... But I don't think they fit ones like that.

I've revved turbo ones in the yard with the bonnet up and noted the hoses getting fatter, so I reckon it boosts any time the engine's up to speed, meself.

and this is another good point. The transit TD here has the same problem, and when the manifold is blowing it don't pull so well. Unfortunately, the simple fix (gun gum around the joint) doesn't last all that long - but the proper fix, which is to remove the manifold, clean the joint and re-seal it (it doesn't have a gasket), would take about half a day, whereas the simple one takes 5 minutes.

Connect a boost gauge and have a look at what happens.

Nice one EMB, you don't mince words. The important point is when the engine is under load it's burning a lot more fuel, and producing much more expanding exhaust gases which drive the turbo faster, turning out more boost. You need to T in an accurate low pressure gauge to check how much.

Martin

I'm never keen on being told I'm wrong when I've given correct advice. Otherwise I'm mostly pleasant and of good humour.

Martin I seem to recall the recommendation was to check with the engine running over 2000rpm and climbing that sound about right ? (I'm imagining it means similar to the climb up from Mottram to Staly 1:20? ) btw you got any RRC bits you want to sell I have a list ;-) Derek

The first bit of advice to anyone with a turbo engine experiencing issues should definately be to fit an accurate boost gauge. until you know what the boost is you are just guessing at other causes.

In my saab, to set up my max boost I always go for a steep hill and then thrash it up it ensuring i get to 4th gear (top in my car).

--

No he doesn't does he?

However, I will at least remain polite in my reply and hold a faint hope that an apology may be forthcoming. I quote the original poster: " at least I can see if the turbo is actually producing any boost. "

My test will tell him exactly if his turbo is producing ANY boost.

He did not ask for an accurate method of measuring boost.

TonyB

I would agree with this. I had a Volvo turbo with a boost gauge on the dash and I was surprised to note that that cruising down the motorway at

I'm afraid you may be under the same misapprehension that EMB is under Hugh. While crusing at 70 you'll have a low throttle opening which results in low exhaust gas pressure, thus the turbo will not spin to full speed. Opening the throttle with an increase in gas flow will spin up the turbo but a load on the engine is not necessary for this to occur. TonyB

Patently untrue Tony. And I'd really appreciate if you'd stop spreading inaccurate information - maximum boost will not occur without close to maximum load (proven over the weekend in several different vehicles ranging from 2.5 to 16 litres displacement, and max boosts from 0.5bar to 4bar).

He's not claimed that it does, he's just said that you'll get *some* boost, not max, so you can at least say that the turbo is spinning. I've seen the same on my old lotus, with no load the boost gauge will give a reading when you boot the throttle in neutral but you don't get much until you're in gear and underway.

As turbo problems are commonly related to worn axial thrust bearings you need to run them up to significant boost to put a high axial load onto them to check. The same applies to a sticky wastegate - maximum boost is often all that is affected.