Loss of Power on Boost - Cupra 1.8T

[ts743]

I am experiencing an intermittent loss of power. My car is completely standard and un-modified (MK1 Cupra 1.8T)

Unlike my previous misfire, which felt quite jerky and aggressive, this feels a lot softer. I'm not sure if this rules out a misfire, but certainly feels different to when my coil packs died.

This is apparent at half throttle, but most noticeable when accelerating flat out through the rev range. It's practically impossible to reach the rev limiter (not that I practice this, but to illustrate my point).

I've very recently changed all coil packs for genuine brand new ones, as previously I was suffering from a very bad misfire, the car ran fine for some time after these were replaced. I would struggle to believe these are bad after very few miles, but I guess it's possible?

Occasionally the EML will come on - and then disappear the next time I use the car.

I have searched, but not really reached any conclusion, bar lots of shouts of the N75 valve. I have disconnected this (electrical connector) and the car shows the exact same problem, even with much reduced boost.

I have disconnected the MAF briefly, the car ran the same without it.

I am going to scan the car today and see what faults are thrown, if any.

Lost for ideas really...

 

[ibizacupra]

faultcodes would be useful if you can read them

 

[ts743]

Indeed - Scanning later today, just though I'd post this up while I was in front of the computer

 

[ts743]

 

[ts743]

I am assuming the last two shown above are due to me disconnecting both the MAF and the N75... and the first two being my fault... any ideas?

 

[ts743]

I've relentlessly googled this and it seems to point to the VVT chain tensioner, mine is rattly on start up, it can sound like a diesel. Am I jumping the gun or could it be something less serious?

I can't even find the part, does anybody have a part number for the tensioner? Is there a sure fire way to test this to see if it's at fault?

 

[ibizacupra]

I would be dropping off the sump and replacing the oil pickup pipe at this point to ensure the oil pump is able to pickup its oil and not cause oil pressure problems.. It *could* be the cause of a lazy vvt tensioner on cold start, but its also fairly common for them to throw this code when they wear out also...

Crank sensor looks iffy also....

when you clear codes, which come back?

 

[ts743]

Forgot to clear them, but will do that and check.

Is it necessary to replace the pickup or can I clean the existing one? Can't seem to find the part on any of the usual parts sites.

If it comes to replacing the VVT tensioner, there seems to be a lot of part numbers flying about, how do I know which I need? Would this suit:

http://www.ebay.co.uk/itm/Spanner-K...arts_Vehicles_CarParts_SM&hash=item43c153e994

 

[ibizacupra]

avoid ebay vvt like the plague - many fakes there.

new pickup pipe is less than £15 from tps

 

[ts743]

I've got myself a new pickup pipe sorted... £9 so very reasonable

VVT Tensioner comes in at £144 or £350 +VAT - The guys at TPS said I'd have to whip mine out to know which one was required (one has an electrical connector, one doesn't?)

Question is, I've heard that the non OEM units aren't worth bothering with, but why exactly?

I always buy OEM on the whole, but have used quality pattern parts before and never had any trouble. The price difference is a good £100+ in this case and the car is a fairly worthless daily hack, I cringe at having to spend anything beyond service costs on it!

Has anyone used a cheapo version? What is to be expected, instantaneous collapse?