Wahts going on with my Cupra

[chr1sd]

Right I'm really starting to wonder whats going on with my Cupra.

Ive had it a couple of weeks, and Ive been ironing out a few issues, mainly hesitation and a few error codes. The first was a boost control valve malfunction, so i have changed the diverter valve which cured that.

Im now getting lambda errors P3266 (intermittent) and Fuel Measuring system errors P1093 intermittent.

Ive been out in the car tonight doing a bit of data logging with VDCS and im puzzled to f@ck.

The fuel pressure at the rail looks spot on. Reading around 50-60 on light load and 110bar on WOT. However, according to VCDS the intake pressure is peaking at 1830mbar in places and averaging between 1650mbar - 1750mbar on 80-100% throttle.

I make that peak boost of 26psi and average peak of 24 psi.

SOOO. The cars is obviously remapped lol but its all stock parts, exhaust, downpipe, intake cooler etc etc. Theres' a rabbit off somewhere. Any thoughts?????

Those pressures must be way more than stage 1 surely??

 

[Dan FR]

You're forgetting they are absolute pressure readings, not boost readings. Subtract atmosphere which is approximately 1000mb or 1 bar and you will arrive at the correct positive/boost pressure.

Have you looked up possible causes of the codes on the Rosstech site - might help

 

[chr1sd]

You're forgetting they are absolute pressure readings, not boost readings. Subtract atmosphere which is approximately 1000mb or 1 bar and you will arrive at the correct positive/boost pressure.

Have you looked up possible causes of the codes on the Rosstech site - might help

I was logging group 118 Field 3 - Boost pressure (actual) ???

Rosstech suggested fuel pressure tests. I have followed their guide and low and high pressure readings are pretty much bang on, and the logging data shows that the pump is making 110bar at WOT.

I was going to try a new Lambda sensor on it, but was worried that the car may have been mapped to stage2 or stage 2+ in the past and someones put it back to standard, leaving the map on it. ??

 

[betty_swollox]

I was going to try a new Lambda sensor on it, but was worried that the car may have been mapped to stage2 or stage 2+ in the past and someones put it back to standard, leaving the map on it. ??

If you are worried I am sure SEAT can put the standard map back on for you.

Could always stick it on a RR and see what power its putting out?

 

[chr1sd]

I see what you mean now, that measuring block is reading 1000mbar at idle so its peaking at a smidge under 1 bar. Im assuming that sounds more like a standard boost pressure?

The bloody fault codes dont seem to point definitively to one place, seems just like general air/fuel issue. The hesitation when it happens comes on on light throttle between 2-3k rpm. Disappears after that. I will try a lambda sensor and might as well stick a MAF sensor in at the same time, the bloody car has had every other sensor

 

[BrownFox]

I had the lamba error on mine. Its one of the hoses attached to the engine has split or is loose look at all the black hoses etc

 

[chr1sd]

I had the lamba error on mine. Its one of the hoses attached to the engine has split or is loose look at all the black hoses etc

Ive just checked them mate and all looks OK. Ive had the timing cover off again just to double check that Ive timed it correctly and it is spot on. The only thin i can think of is when Ive lowered the engine to get the engine mount off it has stretched the lambda sensor cable.

got me baffled now. Been out in the car all day and its chucked the lambda sensor fault up again after clearing it yesterday.

 

[chr1sd]

Well, i put a new lambda sensor on the car and problem seems to have gone. no more lumpy idle and car pulls smooth now, and codes haven't reappeared. Think I'm still going to put a new fuel filter on the car anyway, and keep and eye on things.