Disco 300tdi underpowered

[stevied645]

Hi guys, my 300tdi i just bought seems really underpowered! it feels very flat half way throught the revs, then after 65mph it really struggles to go any faster, it does have 265/75-16 special tracks on it but wasnt much differant when i tryed it on 205-16s, any ideas what to start looking at? i serviced it, new filters etc, all the turbo intercooler pipes seem ok.

Whilst im at it trying to get it going well again i wouldnt mind making it a bit faster/torquer, so any suggestion on how to do this would be great, ive heard a bigger intercooler and having the pump adjusted can make a little difference

[TEMPL4R]

Is the wastegate on the turbo shut? Not stuck open or the rod come off?

The boost pipe to the top of the pump OK.

When did it have a timing belt?

Sump level not high was it?

Chris

[T5SPEEDY]

HI,I HAVE A 1995 300tdi WHICH I PURCHASED IN NOVEMBER THIS SEAMED SLUGISH AT FIRST AS I ALSO HAVE A 220bhp GOLF GTI SO THE DIFFERANCE IS HUDGE.DONT COMPARE IT TO OTHER CARS YOU DRIVE AS DISCOS ARE NOT RACING CARS.JOKING APART YOU SHOULD GET MORE THAN 65 MPH OUT OF IT DONT KNOW IF THE TYRES MAKE ANY DIFFERANCE.THE FIRST THING I DID WAS CHANGE THE OIL AND ALL THE FILTERS,A BOTTLE OFF INJECTOR CLEANER IN A FULL TANK OF FUEL,EGR REMOVAL+DE-CAT EXHAUST,THE POWER+TORQUE AS IMPROVED.IT PULLS BETTER AND I DONT HAVE TO DROP GEARS AS MUCH.I HAVE ASKED ON THIS FORUM MYSELF ABOUT DOING THE PUMP,IT NEEDS DOING CORRECTLY OR IT CAN BE TROUBLE LATER DOWN THE LINE.HOPE THIS HELPS

[stevied645]

Is the wastegate on the turbo shut? Not stuck open or the rod come off?

The boost pipe to the top of the pump OK.

When did it have a timing belt?

Sump level not high was it?

Chris

Hi chris, timing belt was changed 35000 miles ago, not noticed oil level being any higher (what do u mean by this?) and i have checked all the boost pipes, top pipe from intercooler to inlet manifold had small hole, i replaced the pipe with a new one tho.

[stevied645]

oh and ill have a look at actuator 2morrow

[thebiglad]

oh and ill have a look at actuator 2morrow

Bare in mind that with your non-std tyres will affect the reading on the speedo and mileometer.

See here to see the difference:http://www.miata.net/garage/tirecalc.html


Looks like it'll be reading about 9.5% slow, so when speedo is reading 60, you're actually doing about 66mph.

[stevied645]

Bare in mind that with your non-std tyres will affect the reading on the speedo and mileometer.

See here to see the difference:http://www.miata.net/garage/tirecalc.html


Looks like it'll be reading about 9.5% slow, so when speedo is reading 60, you're actually doing about 66mph.

I know this, but it is very underpowered as i said in 1st post i tryed it with a set of 205-16s and no real difference tbh, i can feel its really flat about half way through the revs if i drop it down to 4th i can get 75-80 but as soon as im in 5th it slowly just slows back down to 65mph

[thebiglad]

Hi guys, my 300tdi i just bought seems really underpowered! it feels very flat half way throught the revs, then after 65mph it really struggles to go any faster, it does have 265/75-16 special tracks on it but wasnt much differant when i tryed it on 205-16s, any ideas what to start looking at? i serviced it, new filters etc, all the turbo intercooler pipes seem ok.

Whilst im at it trying to get it going well again i wouldnt mind making it a bit faster/torquer, so any suggestion on how to do this would be great, ive heard a bigger intercooler and having the pump adjusted can make a little difference


Have you cleaned out the fuel sedimenter??

[Satancom]

I would be looking at the fuel sedimenter, air filter, intercooler pipework. When I got my disco I opened the airbox to find a rather filthy aoir filter that had been more or less sucked up the air intake.. Not pretty!

[monty_john]

I'm having a similar problem on my '94 RRC 300tdi, it use to do 90 on the motorway, can't get over 65 now... Tried to check the sedimeter, doesn't have one, so I checked my mates RRC, same. So I checked my sister’s disco and there it was so I know I'm not going blind. A couple of checks I did were,
1) Slacken the nut on top of the fuel filter; fuel squirted out so I assume the lift-pump is ok.
2) Rev the engine, turbo hoses go rock solid, so it seems to be generating plenty of boost.

I know these aren't very technical checks but would assume they are adequate to eliminate certain things or am I wrong.. Any help would be much appreciated...

[skippy69]

Might also be worth the 5 min's checking the EGR unit's red plug & loom for oil ? mine was running a bit sluggish on hills, checked for oil coming from rocker cover, just underneath the front left side. She's running much better now:D Use a good PCB Cleaner to clean the plug on the ECU unit & the loom socket.

best of luck :)

[monty_john]

Might also be worth the 5 min's checking the EGR unit's red plug & loom for oil ? mine was running a bit sluggish on hills, checked for oil coming from rocker cover, just underneath the front left side. She's running much better now:D Use a good PCB Cleaner to clean the plug on the ECU unit & the loom socket.

best of luck :)

The EGR had been blanked off when I bought mine. I reckon mine is an air thing, it's a bit smokier than usual, which was smokey anyway, and the mpg is really low, thinking simply, it must be getting the fuel through, might buy a turbo gauge thing just out of pure interest

[Jim Franklin]

When I bought my 1994 300TDi I had similar issues.


Seemed to be struggling to breath properly
Power seemed to be a lot less than similar vehicles
Heavier on fuel than expected
Unable to drive at motorway speeds
Pulling power was almost non-existant.
I spoke to several people who gave good advise, including the Guys at Scorpion Racing, based on their comments and advise I did the following.


Located the very hidden fuel sedimenter (located on the offside under the rear floor inside of the rear passenger door above the level of the chassis) and cleaned it out..It was truly full of crud!!
Removed the EGR valve and blanked off.
Removed all existing Turbo Hoses and replaced with Silicone ones.
Removed the Intercooler, soaked in Metholated spirit for 24 hrs then flushed out and dried.
Replaced the rocker cover gasket.
Drained all the engine oil after adding engine flush, replaced the Oil Filter and then the Oil.
Replaced the fuel filter.
After all that was done the power was back to what one would expect from the 2.5Ltr TDi. The pulling power was now something to behold, acceleration was well up on previous, the torque was back where you would expect and the top speed was now to 105mph (That was only a test), but the vehicle cruises at 70-80mph with no problem and returns about 32mpg as an average at that speed.

If you have no EGR valve then simply replace the turbo hoses and do the rest..You'll be amazed at the difference it makes.

Jim

[300bhp/ton]

Hi guys, my 300tdi i just bought seems really underpowered! it feels very flat half way throught the revs, then after 65mph it really struggles to go any faster, it does have 265/75-16 special tracks on it but wasnt much differant when i tryed it on 205-16s, any ideas what to start looking at? i serviced it, new filters etc, all the turbo intercooler pipes seem ok.

Whilst im at it trying to get it going well again i wouldnt mind making it a bit faster/torquer, so any suggestion on how to do this would be great, ive heard a bigger intercooler and having the pump adjusted can make a little difference
There have been a few threads on this lately, it might be worth a look at them.

I assume you've driven other Tdi's so have a good basis for comparison?


Your tyres should have some affect as they are big and heavy and will affect gearing, you are also doing very well to top 80mph in 4th too.

The main things are check its all ok, give it a good once over, filters, fluids and so on. It might be worth looking at removing the EGR and cleaning out the intercooler too.

If you get a boost gage you could check the turbo boost levels to make sure its boosting ok, check for air leaks and maybe check the injectors if you want.

Assuming that everything has been checked and is ok, then move on to performance mods. Free flow exhaust, de-cat and then tweak the pump with a bigger intercooler, it should make a lot of difference.

[skippy69]

Might also be worth the 5 min's checking the EGR unit's red plug & loom for oil ? mine was running a bit sluggish on hills, checked for oil coming from rocker cover, just underneath the front left side. She's running much better now:D Use a good PCB Cleaner to clean the plug on the ECU unit & the loom socket.

best of luck :)


Sorry :eek: I ment to say check the " ECU" unit's bottom red plug for the wiring loom for oil !!!! Ooops It's easy to check , just next to the bottle jack & fuse box, if it's soaked like mine was? just give both the loom/plug & ECU socket a good clean with PCB cleaner :rolleyes:

hope ya figure it out ;)