Thread: Loss of power and economy - tdi auto Disco

In standard guise in good running condition, I find a Tdi Discovery has quite good power. If its severely lacking, there is a problem and fitting LPG injection will probably make it worse.

The only time I've lost power and had very poor fuel economy is when my old Tdi disco dropped two injectors all together (the spring inside fractured). I had them tested and replaced at Rankin Diesel in Bayswater.

Although the overheating thing seems to point towards a head gasket failing.

Originally Posted by B92 8NW

Although the overheating thing seems ......

It over heated on a slow climb .... so blocked radiator cores can also do this, as it is a 10 year old car

But the whole story put together .... not nice

You can put a "dye kit" in the coolant to check for failed head gasket ....

Mike

Mike

Is this dye kit a mechanics only tool, or can I pick it up from any supercheap or repco?

Hi Goldey;

Before you get real worried about your head gasket , pull the hoses off the radiator and flush it first ( relatively easy job to do ) , while ago my 300tdi disco was having similar symptoms to yours whereby I 'd lost considerable amount of power and fuel economy was Cr@p , first thing I did was to check the valve clearances 0.2 mm on intake and exhaust side amongst other things ,but was still running like a pig , I took the vehicle down to Graeme coopers and problem ended up being a

Loose Timing belt
also Pump timing was out
Once timing belt re-tensioned and pump timing adjusted and re-calibrated and DYNO'ed the car runs a lot smoother , no rough idling etc more importantly it pulls away very nicely.


hope this helps

also I replaced the standard turbo and intercooler hoses with silicon ones , they're probably costing you extra ponnies.

Pm me if you want part numbers .

Hi Goldey,
Firstly, when was the last timing belt? If it is near replacement or around 70 to 80K old, they will be slack and therefore fuel timing can be out a bit., secondly, as previously mentioned valve clearances are critical on these. .208mm (.008") inlet and exhaust, hot or cold. We adjust/ check them every 10K.
Lastly, the overheating problem is almost certainly a blocked up radiator, the coolant alarm could've gone off due to localised aeration caused by boiling, especially if the sensor is on top of the thermo housing. Is the water level dropping over a few days?

Get the rad rodded out, I bet it is close to 30% blocked.

If the belt is due to be replaced, make sure the pump plunger lift is set to 1.6mm. Factory spec is 1.54mm, believe it or not that .06mm makes a lot of difference. This is a must do for all auto Tdi's.

JC

Blocked radiator cores isn't going to cause an overall loss of power... It's going to be something in the air/fuel/compression mix.

However... It could act as a clue.

I'd be looking ion the following areas first:

• Intercooler - If there's mud in the rad, there will probably be mud in the intercooler... It might well be worth cleaning out the inside too.
• Hoses - Make sure they're sound, connected properly and if they're before the turbo, make sure they're not collapsing when on boost.
• Air intake - Check filter, etc...
• EGR - A clogged EGR valve will be letting exhaust gas into the combustion chamber.
• Valve clearances
• Timing - If the belt hasn't been done in the past few years, I'd change it...

If you're still not getting any oomph, the top end of your fuel pump might be seized (we'll cover that later).

HTH

M

Originally Posted by camel_landy

Blocked radiator cores isn't going to cause an overall loss of power... It's going to be something in the air/fuel/compression mix.

However... It could act as a clue.

I'd be looking ion the following areas first:

• Intercooler - If there's mud in the rad, there will probably be mud in the intercooler... It might well be worth cleaning out the inside too.
• Hoses - Make sure they're sound, connected properly and if they're before the turbo, make sure they're not collapsing when on boost.
• Air intake - Check filter, etc...
• EGR - A clogged EGR valve will be letting exhaust gas into the combustion chamber.
• Valve clearances
• Timing - If the belt hasn't been done in the past few years, I'd change it...

If you're still not getting any oomph, the top end of your fuel pump might be seized (we'll cover that later).

HTH

M

We don't get that useless EDC /EGR engine here thank goodness!
I'd forgotten about the governor pin siezing Camel landy, only came across it once but it was great to find and fix it! transformed the vehicle! All I ended up doing is removing the little Hex key front 'plug' cover and manually moving the pin back and forth with some WD40 etc until it moved freely. Has that been your experience/ fix for them too?

JC

Originally Posted by justinc

We don't get that useless EDC /EGR engine here thank goodness!

Originally Posted by justinc

I'd forgotten about the governor pin siezing Camel landy, only came across it once but it was great to find and fix it! transformed the vehicle! All I ended up doing is removing the little Hex key front 'plug' cover and manually moving the pin back and forth with some WD40 etc until it moved freely. Has that been your experience/ fix for them too?

Not always...

I've come across a few over here where the plunger under the diaphragm has seized too. Once again, it's fairly simple to fix with a can of WD40.

If you do a search, I've posted some words up before on how to do it.

HTH

M