Hi, my 04 cupra has had poor mpg since I got it compared to my old Fabia VRS.

I've now noticed it's doing a lot worse! I've done 150 miles on half a tank, no hard driving or revving the tits off it because my boost is **** poor!

Boost has gotten really bad, sometimes it's there sometimes it isn't I never get full boost I think from the feeling...

Every now and then it goes into limp (overboost) all pipe work seems fine, it's got a brand new intercooler on it cos the last one had a hole in it.

Does anyone have any idea what it could be?

I've done some reading and MPG could be MAF and boost obviously the turbo? I've been under the car and moved the actuator and it seems free and not stiff or grinding?

I plan on doing some logs soon but I've no idea what the values should be on my car to compare.

If anyone could share their knowledge it would be a big help!

Think I've done it.... if not I've a file I could send someone to help?

https://m.facebook.com/story.php?story_fbid=10153609396011427&id=684816426

It's mapped. Stock cupra's request 2550mbar. Yours is 2700. Between 2500 and 3600 rpm it's over boost past the 3bar map sensor limit. Duty cycle doesn't look too bad but it's hard to say with a remapped engine. Could be bad mapping or it could be a turbo fault.

How's the smoke levels?

Very rare it smokes, get the odd puff of black smoke if I floor it.. but that's once in a blue moon.

Would sticking a 4 bar map sensor on sort it? And go from there, if it's no good start looking at getting the map sorted or new turbo...

Would that explain the poor mpg?

My VRS was mapped and was a shed load better on fuel!

Just reading again and where it's over boosting doing some subtracting for atmospheric pressure would equate to 2 bar? Wouldn't that be very dangerous for the turbo? Should be about 1.7 bar max?

I could be very wrong though not a great deal of posts about to try help me make sense of it

Yeah subtract 1bar for atmospher to get pressure I. The pipes. Yes 2bar isn't good for a stock turbo . Fitting a 4 bar (along with map tweak for the new sensor) would allow you to see what it's actually boosting to. Could be 2.5 bar! But that's not fixing the problem. You need to find out what's causing it to overboost so much.

Where you based? If local I can put a stock map on to see if it still overboosts.

Hartlepool pal, where are you located?

Liverpool

Canny drive out!

Is there any other logs I could be doing to try narrow things down?