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Cupra tdi - signs it's losing power slowly

Toby Davis

Toby Davis

Toby Davis
Oct 12, 2009
602
0
Kidderminster West Midlands
Hi guys been a while, just wanted some advice. I own a ibiza cupra tdi remapped. It's still pulling strong but noticed when at santa pod it was gutless after 100mph, but pretty fast up to it. Peek boost has also dropped from 26-28 to 20/22 psi if I am lucky. Checking maf on vcds indicated its actual air is a few hundred than requested when idle. It did however appear to be working fine on full load. Just feel my car is being zapped on power really slowly, picking up on small signs something's up, can anyone advice ?
 
Can't here any sound there is a boost leak, all pipes secure, no lag or turbo delay, vac pipes seem fine. Have noticed on start up in the morning it can be very, very smokey and sometimes the engine actually bangs around and makes a loud knocking noise (reacting like carb cleaner has been sprayed into egr) that seems very wrong to me ! Fuel filter changed very recently and serviced, cone filter clean, car always starts fine, never stalls. Any ideas folks - map sensor perhaps ?
 
Reference the MAF reading, ignore the specified at idle as no doubt the EGR has been mapped out and shows 850 and the actual is about 450-475?

Have you checked for boost leaks? Does it smoke badly?

EDIT - Just seen your second post.

Have you tried running some WOT logs of 3rd and 4th to see what's happening? Log Groups 3, 4 and 11.
 
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Just the man I hoped would respond. Believe on idol it was requesting about 300 ish and was actually at the 450 ish you stated. Not an expert with vcds but the tests I did showed the maf working very well and being at and above the requested figures on full load in 2nd, 3rd and 4th gear. From experience if I have a boost leak I can always here it . Remember on old tdi it was gutless at 100 then it creeped down and down until it had nothing. Changed maf, problem solved. Mine appears ok though
 
Got a 14.9 at the pod so assuming that's a fairly good time and typical of a remapped one ? Just had nothing after 100 making me think maf! Just like before. Heard they make you lose power very slowly
 
Well the ECU is only expecting to see 300mg of fresh air through the MAF and the rest is filled through the EGR, however, the MAF is getting more which would suggest the EGR is stuck shut.

Also running logs of group 11 will show if the turbo is pushing enough air around and log group 7 for intake air temperature.
 
When I turn the engine off and pull the key out I can sometimes here the flap shut inside the egr valve, don't people who block the egr valve off experience this issue then ? Trying to avoid using vcds as I don't really understand it or how it will help solved issues as I won't understand figures shown :(
 
Sorry badger, just seen your reply, update for you. Found a very long, quiet stretch of road, floored it and car pulled well up to the usual set speed then was gutless, no increase in speed and I could smell the clutch burning I believe. Always does it on hard acceleration, and only does it when you keep trying to push it past the limit the car won't move from
 
Clutch seems fine otherwise, pulls well in all gears, no signs of clutch slip ever (increased revs no speed etc). On the way back it was down hill slightly and it flied past the limit it usually stops at, on a straight road however, its utterly gutless and won't go past this figure despite pulling like a train up to it, cars not in limp mode, no lights on dash etc, just gives up and smells of burning when you keep your foot down after it won't move
 
It's gonna be difficult to diagnose without vids logs though. Could be a tiny boost leak - not all of them are audible.

I had a right curve ball when I had your problem. There was a tiny crack in the pipe between the air box and where the EGR is. This meant that the MAF was thinking it was working properly and getting the right amount of air in, then loads more air would come in at the crack.

The symptoms were very sluggish very late boost (though no peak boost issue) but no other problems.

Worth checking vacuum lines and around the MAF for leaks?
 
Thanks for response, car has a cone filter on using the standard pd160 intake which goes straight to the cone filter. Checked all boost pipes for leaks and all vac hoses are new. Cleaned map sensor an hour ago as it's free to clean, not expecting that to change anything though :(
 
I can log tonight but what should I set the baud rate of the com port to ? it doesn't work unless you change it and I don't want to make thee figure up and effect the results ?

Do you only need me to log groups 7 and 11 ? can I do them at the same time ?

3rd gear 1500rpm up to red line I assume is all that's needed ?
 
Going to log 3,4 and 11 at the same time through WOT from 1500rpm in 34d through to 4th gear and set the baud rate to 9600 as that makes it all work. Leaving in 30 minutes so please respond bt then if you can if you don't agree with any of the above, thanks
 
Sorry only just saw this. Not sure about baud!

That should be enough logs. Just make sure you drive through the rev range. The 3k in third gear doesnmt really show good data. Much better just logging acceleration through the rev range.
 
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