EGR valve problem

[johnnyboylager]

Hi guys - first post on this forum.

Hi guys

Recently bought my son his first car, its a 2004 VW Polo 1.4 petrol.

Bought from a friend at mates rates, Great condition, he was the first owner and has really looked after it.

The engine warning light on, and I spoke with him about this he was very open about it. His mechanic was reluctant to try to remove the EGR valve to replace / clean as the 2 studs & nuts (M8) that hold it to the manifold are very rusty.

Its been like this for 3 years and he never noticed any problems driving it so the mechanic advised him to leave it alone and just reset the light the morning of every MOT. It seems to come back on after 24-48 hours from my experience so far.

My suspicion is that the EGR is stuck open or partially open, fault code is "Exhaust gas recirculation flow excessive".

I've noticed that the car is a little sluggish when accelerating, particularly when pulling away in 1st gear (manual) - which I am managing OK, but my son is struggling a bit as he is still learning to drive.

1 - I'm wondering if the EGR problem could be causing this sluggishness?

2 - Today I reset the engine light again and disconnected the plug & socket to the EGR. I expected the engine light to remain on and not be able to reset - but it has stayed off, even with engine running. I have not taken it for a run as yet, just idled on the driveway.

-----------------
EDIT - the engine light came on after driving about 3 miles, with the plug completely disconnected from the EGR valve body. I don't know if that plug / socket just powers the EGR, or also sends a signal to the ECU which triggers the engine light - maybe the signal comes from a sensor elsewhere? Fault code is "P0402 Exhaust gas recirculation flow excessive detected."
-----------------

I have been soaking the rusty studs and nuts with WD40 since the car arrived, just in case at some point I do decide to try to remove it, but I must say I agree with the mechanic, they do look very corroded and I would have the exact same worry about breaking 1 or both off, which would open a whole can of worms as its not easy to get to to drill out and retap the manifold/replace the studs.

Any mechanically experienced people able to offer me any advice?

To me the car drives great and we are really happy with it, I just can't help feeling that it would run and respond better if this were sorted.



Thanks in advance.

Johnny.

[RUM4MO]

Maybe try following the metal pipe from the EGR valve to the area at the TB, that is typically where any blockage is in my experience of a single 2002 1.4 BBY engined Polo. The blockage will be where the EGR valve exhaust air is passed into the inlet plenum area, made worse by the extra engine oil being allowed to fed into that inlet plenum by a duff air/oil separator - see my extra comments below.

Unfortunately, this engine has been well described when it was first in use as "a dog", my personal experience over 13 years and 105,000 miles with a 5 speed manual gearbox definitely agrees with that. That engine was not fit for purpose back in 2002 when compared with the competition, poor performance, poor drivability and poor fuel economy - the worst car buying (for my wife) mistake. The later version, maybe BWX is a lot better in every way. The air/oil separator can cause it to drink too much oil and "ping/pink" badly, but that can be offset by using 97 octane fuel - or replacing the air/oil separator.

[johnnyboylager]

hi thanks for the reply, Im not sure what you mean when say "follow the pipe" - I cannot remove the EGR fixing nuts (for fear of breaking the rusty studs) - are you saying there is something I can check or access without removing those 2 M8 nuts?

[RUM4MO]

I don't have that car now, moved onto a 2015 Polo 1.2TSI 110PS, so I can't have a look and be more specific, but I thought that that pipe could be unbolted at each end and its support clip/bracket unbolted, and it could then be taken off the car completely, then you can unbolt the TB and see if the area where that pipe's gases pass into the inlet plenum, is blocked/choked with black greasy gung - or not. I suspect that it is blocked, it might be easier to just disconnect the TB area end of that EGR pipe and then remove the TB - I initially felt the need to check that the pipe was clear - which it was, before looking at the TB area when the gases pass into the inlet plenum. My first plan was to remove the EGR valve, as I suspected it was choked like many seem to be - but that seems only to be a TDI issue, the petrol engine's EGR valve seems to stay clean.

Cleaning out that choked gas passage or hole sorted things out for me, though a few years later I bought cheaply a NOS EGR valve and fitted it - but that was in a vain attempt to get rid of the pinging/pinking issue - it did nothing for that, which for me proved that replacing that EGR valve was a waste of time and money, but I was desperate to move forward with these issues and didn't hold back on spending money, this was war, and either the car, or I would win! Eventually I worked out that it was the air/oil separator that was causing too much oil to get through into the intake manifold and the Lambda sensor was turning down the incoming fuel to compensate for the oil coming in, but oil has a lower octane/anti knock number than petrol and so ping/pinking was happening!