Any idea what the engine revs are when flat out? Does it sound 'busy' or rather less than you might expect?
Has someone been fiddling with the fuel pump high idle setting? It might be worth getting someone to check it.
If that side's OK it looks like a lack of power issue (very different to lack of torque) which could point to air/exhaust or fuel flow restrictions.
Any dragging brakes? No huge roofrack?
Check the entire air inlet tract from the air cleaner back to the turbo for blockages and collapsed hose linings. Is the fuel system clean? Checked all filters/sedimentors?
Non-standard bevel gear and transfer box ratios are also possibilities but it's unlikely that the speedo would have been changed to compensate and give you the accuracy that you've confirmed. I'd consider that as the last resort.
But checking the bevel gear ratio is very easy, the most likely gearing change and might save you a lot of effort if found to be other than the 3.54 ratio expected.
Is the turbo working? - have you got a boost gauge on it?. could the wastegate be stuck open or something? (happens on the saab turbos which im used to)
can you turn the injection pump round on a 200tdi to give it a bit more fuel incase its timing is out? You could get a diesel specialist to check it out (a diesel specialist not a normal garage)
Should give you more wellie, so if everything else is working, can only be the gearing that's been changed. If the previous owner was off-roading or towing a lot then perhaps they modified it to suit with intercooler, lower gearing and matched speedo.
On 235 tyres, I used to get something around 75 out of mine, though the engine was going some. Don't forget that 90's have different ratio transfer boxes, so they will always have a lower top speed than a 110, whetever tyre sizes are fitted (within reason).
First the principle involved - if you keep one output of a standard unlocked differential stationary the other output will rotate at twice the normal speed for the same input speed.
So, for a 3.54 bevel gear ratio (substitute actual value), 3.54 turns of the propshaft will normally give one turn at the road wheel. With one wheel held stationary it will give two turns at the other road wheel. It also works from the other end so, hold one wheel stationary and two turns of the free road wheel will turn the propshaft 3.54 times.
Chock the wheels if you are going to use the rear axle as you will have to release the park brake. Diff lock off and one gearbox in neutral.
Raise one wheel on the chosen axle. Rotate it twice and count the number of turns of the propshaft. That's your bevel gear ratio.
That'll get you directly to the answer, is quite accurate and requires no arithmetic. But you could also turn the wheel just once and double the number of propshaft turns to get the final figure etc..
The other standard ratio is 4.7 but many intermedaite values have been created in the aftermarket.
Check for an air restriction, collapsing pipe, clogged air filter, blocked snorkel ETC
Check you are getting boost
If not look at intercooler hoses and the boost pressure metering pipe that runs tot he top of the injection pump and to the turbo wastegate for holes or splits. Also check that the wastegate is not stuck open (very unlikely)
If boost is OK it could be the very small pin that runs on the cam inside the pump that is sticking.. Happened on mine and got worse and worse until in the end the engine would not come off of tickover.
Listen for a ticking noise ( bit like and exhaust blow) could be head gasket.
I had similar problem on my disco, found out that the fuel intake pipe within the tank was almost completely blocked with crap,thereby stopping the amiunt of fuel gong through to engine. cleanedit out and now it holds its own again. B4 it would get to about 65/70 and just not go any more.
Hope it helps
Tony
"Mark Solesbury" wrote in message news: snipped-for-privacy@individual.net...
Right - Removed all air piped and filter. is still some oil clinging to the outside of the pipe that goes from the top of the filter to the turbo inlet - so ill be off to get a new one of them shortly.
The turbo 'fan' spins ok, and it gets hot after a run so i assume its working.
There is a pip from the bottom of the turbo to the intercooler i think - this is very thin and has lots of give in it, ie i can squash it. Is this normal?
Just been out for another run, and it hit 70 this time - But it was defo near flat out and was chucking out a fir bit of black shit...
easy way to find if its working is to (engine running) squeeze the top pipe between the intercooler and plenum chamber then open the throttle or get an assistant to, if its working you will feel the pipe inflate under your fingers but to get accurate picture you need to put a pressure gauge on and take her out for a run the procedure is in the WSM
on the Disco ( I checked the Defender WSM it appears the same) there are two short flexible pipes with a long metal pipe between you need that flexiblilty to allow for the rocking of the engine under (and coming off) load
black smoke is usually excess fuel or not enough oxygen have you put on a new air filter
MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.