PD150 poor mpg

atreyu

Active Member
Nov 16, 2015
38
0
Can anyone advise on improving the MPG from my 2003 Cupra PD150?
Today, driving to work which is under 30 miles, with a mixture of roads I got 37MPG, this was steady driving.

To me that is terrible as I keep seeing figures of 50 being quoted!

The car seems to run fine, smooth etc.

I was wondering if it could be the MAF, but then I doubt it would run smoothly?

I've also read about the coolant temp sensor causing MPG issues? It reads 90 on the gauge, however I have an OBD2 Bluetooth reader which does read lower than the gauge when hot, around 75*c, but I'm not sure that's enough to cause an issue?

The cars done 120K so hardly worn out! Always run on Quantum oil and had a fuel/air filter change 6 months ago.

The EGR has also been deleted.

Anyone??
 

masterfrodo

Active Member
Jul 29, 2016
267
8
thats really not good figures

I was going to suggest getting the EGR deleted, but you have done that

With my 04 Cupra PD150 with the EGR disabled I now average around the 50mpg on a run, was 46mpg with the EGR working

Does it take a long time to warm up? Mine takes about 4 miles before the needle moves. If its taking longer than that it could be the coolant sensor, or even the thermostat

But I really can't see why you would be running as low as 36mpg on that sort of run unless you are driving hard. Can you set the mpg to show and see how your foot affects it. With my foot down I can get into single figures, but driving steady it will get into the 50's quite easily
 

akchappers

Active Member
Jun 27, 2010
3,069
7
Gillingham Dorset.
To be honest mate it depends how heavy your right foot is though I would have thought you'd be seeing more than that. I get 45mpg out of my remapped Alhambra... and that weighs more than the moon and I AM a heavy footed person!
Guessing no lights on dash? Any fault codes?
Ak
 

atreyu

Active Member
Nov 16, 2015
38
0
No it doesn't take too long to warm up. Quite quick for a diesel really. I have an Alhambra too, and that does take ages to warm up!

No fault codes and no lights on the dash

This was driving fairly steady, but keeping up with traffic. Completely normal driving.
 

akchappers

Active Member
Jun 27, 2010
3,069
7
Gillingham Dorset.
No it doesn't take too long to warm up. Quite quick for a diesel really. I have an Alhambra too, and that does take ages to warm up!

No fault codes and no lights on the dash

This was driving fairly steady, but keeping up with traffic. Completely normal driving.

Did you say you've got an Alhambra and it takes ages to warm up? Did you know there's an auxiliary diesel heater underneath to warm the car up quicker??
 

chriswales6

Active Member
Mar 2, 2016
294
47
As said above did you see any fault codes?

The actual temperature will vary depending on engine workload and speed of the car. The gauge on the dash will just give a general indication of the temperature. This is to avoid people panicking if the gauge kept moving around. Sounds like yours is working fine.

The PD150 engines can suffer from camshaft wear which results in poor fuel economy, maybe worth having it checked.

Would also be worth jacking the car up to check if any of the brakes are binding.
 

atreyu

Active Member
Nov 16, 2015
38
0
I recall it's only had a couple of owners before me and I've no recollection of it having had the camshaft changed. I do know they suffer issues but I would have thought it would have been a little more obvious. Why would that cause poor MPG? The engine runs smooth and quiet, no tappet/upper engine noise.

Worth bearing in mind I've had the car 3 years and it's always been the same, in summer I've had 45 on a decent run.

On the way home from work I got 39mpg (I'd guess it warmer outside on the return run)


(Yes I'm aware of the Alhambra having the aux heater, which doesn't always work but that's another issue)
 
Last edited:

Alexis27

Active Member
Dec 20, 2009
2,095
451
Manchester
Might be worth actually checking 'manually' instead of relying on the onboard computer.

Check tyre pressures as well.

There's also the Italian tune up as well! Rev the nuts off it and do a run in a low gear as if you had a DPF to clear.
 

sockpuppet

Active Member
Apr 30, 2007
837
4
Thermostat needs changing if it's only getting to 75 degrees, it should be around the 90 mark, the temp gauge in the car will show 90 if the real temp is 70 or 95. The other thing to check is the turbo hoses as they can gradually ease themselves out on one side so you only lose a tiny bit of pressure and don't really notice as it's so gradual. I found a 1/2 cm gap on one side of the hose going into the pancake pipe, after reseating the pipe all the boost figures stayed the same, but the performance and the fuel economy have both increased.
 

atreyu

Active Member
Nov 16, 2015
38
0
Thanks Sockpuppet. I'll give it a run out and monitor the water temp. So we are saying it should run at 90*c when fully warmed up? measured from the OBD2 and NOT the gauge?

Can the Torque OBD app be trusted for measuring boost figures?

I was looking on ebay at hard pipe kits, my cars totally standard apart from Audi wheels but I'm well aware of the VAG pipework fittings not being great. Is a hard pipe kit a worthwhile investment?
I saw a Chinese kit on ebay
http://www.ebay.co.uk/itm/162129717071?_trksid=p2060353.m1438.l2649&ssPageName=STRK:MEBIDX:IT

I've read some good reviews on a golf forum (when I googled it) anyone on here any thoughts? I only read a few people saying to inspect the welds (which I can sort if required)
 

akchappers

Active Member
Jun 27, 2010
3,069
7
Gillingham Dorset.
Chinese stuff? I'd avoid. Mate got a Chinese turbo, bugger split in two...
But temp changes depending on how your driving it and temp outside etc. As said the gauge is only a guide to stop people thinking the car is about to detonate!
Ak
 

atreyu

Active Member
Nov 16, 2015
38
0
AK, I'll get back with some more figures later

I can understand avoiding the Chinese turbo, but alloy tube I'd say is a far simpler thing. As long the bends are right and tolerances?
I reckon the Darkside or Allard kits probably use Chinese tubing, just bent over here?
Theres a hell of a price difference to get a UK kit, are they a good idea on a standard car just to prevent boost leaks? (Which may be my issue?)
 

Thai-wronghorse

Self proclaimed Cupra R addict & butcher!
Dec 3, 2015
2,195
1,037
Kent
I've looked at those kits numerous times and I'm completely convinced they're the same kits Darkside Developments sell albeit without their alloy clip connectors and Darkside transfers stamped onto the silicone hoses.
They do the same with numerous products including the alloy SMIC which i have first hand experience with.

Sent from my SM-G930F using Tapatalk
 

atreyu

Active Member
Nov 16, 2015
38
0
I've looked at those kits numerous times and I'm completely convinced they're the same kits Darkside Developments sell albeit without their alloy clip connectors and Darkside transfers stamped onto the silicone hoses.
They do the same with numerous products including the alloy SMIC which i have first hand experience with.

Sent from my SM-G930F using Tapatalk

That is really tempting then, I presume everything looks correct in the picture? With me not being too up on the Leon, I don't know what I should be looking for! :rofl:
 
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