LC TDI Slow?

[aBoijj]

Hi folks. This is my first plea for help on here.... hopefully someone can offer some assistance.

Background:
I bought me a Leon TDI Cupra a couple of weeks ago (old car was Mk4 Golf PD115, remapped and had a panel filter). I wasn't able to put my foot down on the test drive before I bought it as it was hammering down with rain at the time.

Now this is a nice car except two problems... I'll deal with one here and start another thread for the other problem as it seems completely unrelated.

Ok, so this problem: The power delivery doesn't quite match up with what I was expecting. I'm not sure how to describe it beyond it feeling like the boost's been turned down a bit and it's more laggy than I would expect it to be. Doesn't feel like I would imagine limp mode to be. I get the usual turbo whistle, and a kind of air-escaping-from-somewhere type noise, which I can only imagine is a boost leak.

What I've done about it so far:

• I've bunged a couple of doses of millers through when I filled up with Shell Diesel Extra from one of my two usual stations a few days ago, but that has had little (if any) effect.
• I've ordered some dielectric grease to bung on the MAF plug - this should arrive in the next couple of days.
• I've inspected what I can of the hoses and, as a result, ordered replacement intercooler inlet/outlet hoses as they appear somewhat looser at one end than the other (as if the notch on one side of the collar is broken), so I'm guessing they're fubar - a search had revealed that these pipes are considered a weak point on these cars. I'll be fitting these at the weekend, weather permitting.
• Replaced the air filter for the one I had on my old car (Will at p-torque told me this would be fine).

Now, is there anything I've missed or something else I should check?

 

[volvic]

does the car produce black smoke? as in more than you'd expect?

i think vag com would be able to tell you if you've got a boost leak... something about seeing how much the ecu requests against how much is actually received? someone will confirm this...

 

[aBoijj]

I've not got vagcom but I have got a v-checker pro and that showed no fault codes after the test drive. I'm not really sure how to manipulate it to give much more information at the moment.

As for black smoke it's not noticable when driving casually but I did notice a bit when I put my foot down coming out of a junction, tho not as much as my old 306 did a few years ago when the glow plugs went - that was a lot of smoke

Talking of glow plugs, I'm pretty sure I saw in the history that this car has has its glow plugs replaced at some stage.

 

[sssstew]

glow plugs wont be related to this, direct injection diesels dont actually need them to run, but they just help with smoothness and quicker starting during low temps.

I still think your looking a little boost leak, maybe not enough to trigger limp mode yet. Then you could also look at logging boost and MAF requested vs actual with vag com to check for both of them.

 

[seat_lion]

sounds possibly like a boost leak or sticky vanes on the turbo best bet is to see if you can get down the back of the engine and see how freely the actuator moves it should roughly move about an inch

read up alot about this last night as im having a pain with one of my cars and no power aswell

 

[george130]

Is it nothing to do with the hot weather were having? I.e. Heatsoak...?

 

[Mr.H]

Boost

Sounds like a boost leak, could be a split hose or bad joint. Weak fairy liquid/water mix makes good leak detector, put sum on joints, bends n unions in pipe work n look for bubbles after a quick drive up to boost n back. If no leak/bubbles n no extra black smoke it could be the wastegate actuator, not closing fully and that would make the car feel sluggish in the lower rev range (below about 3000rpm.) Boost gauge would help you work this out, need to know factory settings for boost + tuning history?

 

[aBoijj]

Replaced the rubber hoses that connect to the intercooler yesterday and it's made a noticable difference. I'm thinking this has probably solved it. Now all I need to do is find out what the whining noise is.... I'm thinking maybe wheel bearing.

 

[Andrewcupra TDI]

whining noise for me was out of shape tires they had pleanty of tread on them almost new , and were XL rates budgets , swapped backs to the front and instantly shifted noice to the front , so they will be replaced soon

 

[aBoijj]

Ahh, so maybe that could be the same for me - my fronts are XL rated budget tyres (came on the car). I'll do my best to wear them out soon so I can replace them! Now where's Will from P-torque when you need a remap?

Thanks for that.