Low Power and Bad MPG - 1.9TDI PD130 AWX

[iTDi]

Hi all.

Long story short: Bought private and only noticed problems on way home. I noticed because my previous car was a Skoda Superb with the same engine: a 1.9TDI PD130 AWX.

Symptoms:

1. Throttle hesitation - press it and engine takes about a second to respond.
2. Low power - feels like 90bhp.
3. Bad MPG - I get 38-42mpg average on a 50 mile journey that I normally got 50mpg.

Observations:

4. Got it checked on VCDS - no codes.
5. Disconnected MAF, performance was worse.
6. Exhaust is smokey (like after being started from cold) - expected overfuelling.

Vacuum System: (this is the interesting bit)

7. I attached a clean tube to the EGR valve and sucked hard, nothing budged. With engine on, any blip in the throttle results in the valve making a farting noise. I don't know if it's actually working.
8. The anti-shutter valve is NOT working.
9. VNT actuator operates on engine start but doesn't move unless given a lot of throttle.

My own VCDS-Lite (unregistered at present):

10. Still no faults.
11. Engine warm, dash says coolant is 90°C but VCDS says it's 79.2°C. This could be the source of the bad mpg problem...
12. ...er, have to register VCDS Lite to scan for faults :(
13. Injector quantities all within +/- 0.5mg/hr at idle. Nothing to suggest worn cam lobes.

Anyone else come across similar problems before? 03 Passat B5.5 1.9TDI PD130 AWX 120K miles.

Thanks in advance ;)

[yaman]

Have you checked the air and fuel filters?

Regards
Jim

[Peter_HMR]

The turbo vains could be sticking. It may have been babied by the previous driver. You could remove the piping and check the trubine blades and measure the travel on the actuator.

[PCDoctor]

Ignore what the dash says when it comes to reading the temp.. It is only a guide and you will find many posts with vcd reading one thing and dashboard reading another

Trust me been there shelled out and same readings

Buy yourself some diesel treatment and give it a good thrash these engines are rock solid and need a good blow out sometimes.. im using millers and running a treat now

[scotty33]

I had a temperature issue on my AVF estate, running at 75 deg C (g62 in vag com) I had previously changed the temp sender, so changed the thermostat, the seal for the 'poppet' was dodgy, allowing some coolant flow at all times.
If you have not come across it already, follow tdi healthcheck on Martin 1810's excellent site:

https://sites.google.com/site/1810martin/home

[PeteK]

I would try replacing the coolant temp sensor first, you can get a genuine one off eBay for approx £12. Also you mention that you disconnected the MAF and it ran worse - this is to be expected and doesn't really prove anything at all. I tried disconnecting the MAF on my own car and it seemed to have no boost at all; always fit a genuine VW MAF and not one of the cheaper ones off eBay - they are about £100 for a genuine exchange one.

[PCDoctor]

From what you have said it does not really point to your temp sensor but is a cheap route to close off

90 on the dash and 80 on VCD is a very typical measurement / if the dash is low and VCD is low then you need to look at temp sense or thermostat but you are looking fine...

Having a good read of martins web site there are a few measurements you need to record particulary boost.. check all the big pipes before and after the intercooler and the one that goes into the egr valve..

It sounds odd but those aluminium couplings wear and let air out and the o rings split..

[iTDi]

I used VCDS to measure the coolant temp on my 'good' car, a Skoda Superb - also with an AWX engine. It gave the same readings.

The turbo actuator also worked similar as the car revved.

The fuel filter was changed 16,000miles ago but I happen to have a Mahle replacement so might as change it.

I've found Martins website excellent but must read it in more detail. Is VCDS Lite good enough for DIY testing if I registered it?

Thanks everyone for the advice so far.

[caldirun]

Hi all.

Long story short: Bought private and only noticed problems on way home. I noticed because my previous car was a Skoda Superb with the same engine: a 1.9TDI PD130 AWX.

Symptoms:

1. Throttle hesitation - press it and engine takes about a second to respond.
2. Low power - feels like 90bhp.
3. Bad MPG - I get 38-42mpg average on a 50 mile journey that I normally got 50mpg.

Observations:

4. Got it checked on VCDS - no codes.
5. Disconnected MAF, performance was worse.
6. Exhaust is Smokey (like after being started from cold) - expected overfuelling.

Vacuum System: (this is the interesting bit)

7. I attached a clean tube to the EGR valve and sucked hard, nothing budged. With engine on, any blip in the throttle results in the valve making a farting noise. I don't know if it's actually working.
8. The anti-shutter valve is NOT working.
9. VNT actuator operates on engine start but doesn't move unless given a lot of throttle.

My own VCDS-Lite (unregistered at present):

10. Still no faults.
11. Engine warm, dash says coolant is 90°C but VCDS says it's 79.2°C. This could be the source of the bad mpg problem...
12. ...er, have to register VCDS Lite to scan for faults :(
13. Injector quantities all within +/- 0.5mg/hr at idle. Nothing to suggest worn cam lobes.

Anyone else come across similar problems before? 03 Passat B5.5 1.9TDI PD130 AWX 120K miles.

Thanks in advance ;)
on points 7,8 and 9. loss of vacuum, may all be down to the split diaphragm on EGR (farting!), change this first, about £120 from VAG. A strip and clean of the inlet manifold and valve at the time of changing the EGR may sort it all.

[PeteK]

The first thing I would try is the MAF just to rule this out - very easy to do and you can just swap it off your Skoda as it will be the same part.

[scotty33]

9 is correct,

When the engine starts, the actuator rod should shorten (move vanes to make boost) it only extends (to stop making boost) at high rpm when the engine is in neutral. Under load this is different but not possible to observe without a dyno!
The rod extends again when engine is switched off as vacuum is lost

I don't know what you can do with vcds lite, if you can read measuring blocks it should be fine, if not may be worth swapping the inlet air pressure sensor or thrust sensor as vw call it. Mounted on the hard plastic intake pipe on the side near the battery.

[PCDoctor]

Vcd lite does do measuring blocks.. and reads error codes

The unregistered version gives limited auto fault code measurement but the licence version will fully scan

Trust me download the free version and get a cable off flee bay for about £15 you wont look back

[martin1810]

Is VCDS Lite good enough for DIY testing if I registered it? Yes. It will tell you all you need to know.

[iTDi]

The oil warning light came on last night (yellow) and even though I topped up and have checked the level 20 times it isn't going off. I have yet to check the bonnet sensor but I wonder if I have a fault with electrics? Isn't the Anti-Shutter valve actuator controlled by a solenoid? I can move it by hand quite easily but haven't checked it by vacuum. I better register VCDS and do a full scan (which it won't do if unregistered).

PCDoctor: Thanks, I have a cable that I got from Gendan for £20 delivered.

[iTDi]

The first thing I would try is the MAF just to rule this out - very easy to do and you can just swap it off your Skoda as it will be the same part.
The problem is I've sold the Skoda to a family member who lives far far away. I was able to test it because I visited them last weekend ;-)

[helpmeguys]

Loss of boost could also be down to hole in intercooler....can hear a whoooshing from inside the car if it is big like mine was. Took me ages to find.