Low power issue thats bugging me for a year... Seeking help

[Connor H]

so is the 9.4% actually -9.4%? minus fuel trims means rich, positive means lean. does it have standard auq injectors in it? it be doubtfull its a bent rod if the car feels fine for a while on a new maf but then starts tailing off again over a week or two.

when i got my auq stage 2 i noticed that it was overfueling upto and around -12% ltft, so i bought a mpps cable, downloaded the map and edited the krkte to scale the bam injectors that id installed back down so that it was closer to 0.0%, it made a big difference in how the car drove, was much more responsive on the throttle since the ecu wasnt having to pull as much fuel back. although this doesnt sound like your problem i dont think.

Honestly i cant remember, i measured it and checked against the thresholds and it was fine so moved on. I will have another glance at them soon once its used to the new maf.

yeah normal injectors. I know there is 100% something wrong with it because ive been in two other 1.8t's at the same power level. if I cant figure out im not bothering with a 1.8t specialist 3 hours away, ill just look for another cheap cupra and part this one out and be done.

 

[mty12345]

="Connor H, post: 5103196, member: 123323"]
Yeah mate completely fed up, so this is very much appreciated.

Just ran the logs for you now buddy, took her from 1.5k to 5k rpm on multiple pulls, the VVT stays firmly off at all times. Load was over 100% on multiple occasions and nothing. Seems it only functions at cold start and that's it.

Happy to run any other logs you need.

 

[Connor H]

Just ran the logs for you now buddy, took her from 1.5k to 5k rpm on multiple pulls, the VVT stays firmly off at all times. Load was over 100% on multiple occasions and nothing. Seems it only functions at cold start and that's it.

Happy to run any other logs you need.

Damn, when you're right you're right! Thank you so much for proving me wrong. That was the last thing i could find, i am at a total loss now. Guess i better start saving up for another leon. Not many around anymore either

 

[mty12345]

Damn, when you're right you're right! Thank you so much for proving me wrong. That was the last thing i could find, i am at a total loss now. Guess i better start saving up for another leon. Not many around anymore either

Tbh i was realy hoping i was wrong for your sake, but at least we know for sure now.

I'm guessing you've probably already tried it, but I couldn't see it mentioned, have you replaced the fuel filter?

 

[Connor H]

Tbh i was realy hoping i was wrong for your sake, but at least we know for sure now.

I'm guessing you've probably already tried it, but I couldn't see it mentioned, have you replaced the fuel filter?

Me too mate. Ive thrown money at the issue for a few years, I cant think of any other reasons why the airflow would be reduced. Feel like setting it on fire now. Really thought id get to the bottom of it... People probably think im just talking up a non-issue!

fuel filter has been replaced in my ownership.

Ill probably do another round of logs, do the obvious, fuelling, timing etc. Might check the exhaust doesnt have a blockage. Other than that, maybe my clutch could be at fault at a reach... but its rated for fair bit more power than i have, and i dont think i have the spirit to take the gearbox off again lol. Worse thing is if i sent to say R tech or badger 5, itd cost me thousands. Totally not worth it!

 

[ExiledWeegie]

id be thinking about it being the ecu if youve changed and checked everything else, what did tuning technics say about it? hes usually pretty good at this stuff in any videos ive watched of his

 

[Connor H]

id be thinking about it being the ecu if youve changed and checked everything else, what did tuning technics say about it? hes usually pretty good at this stuff in any videos ive watched of his

i know hes great and very clever, but he simply didnt care and just tuned around it, even though he agreed it felt off. a few months later i was left with a car reading 150gs again.

could try a different ecu i suppose, will need to source a cheap immo off one. Pretty reluctant to spend any more money at this point

 

[BadBoy03]

This is rough for you mate, you've given it everything you can & it's still being a pain in the arse. I really hope the answer is lurking around the corner

 

[Connor H]

This is rough for you mate, you've given it everything you can & it's still being a pain in the arse. I really hope the answer is lurking around the corner

The only thing lurking round the corner is the scrap!

 

[ExiledWeegie]

if i was closer id let you try my ecu on it see if it made a difference, ive got another ecu there with a stage 1 on it but its got immo on for my car.
its got to be maf or or ecu problem youd think though if a new maf works for a while then its tapers back down to the 150g/s after a while and the only cure is a new maf again, must be wiring or something internal to the ecu causing it.

 

[Connor H]

if i was closer id let you try my ecu on it see if it made a difference, ive got another ecu there with a stage 1 on it but its got immo on for my car.
its got to be maf or or ecu problem youd think though if a new maf works for a while then its tapers back down to the 150g/s after a while and the only cure is a new maf again, must be wiring or something internal to the ecu causing it.

I keep flip flopping between it being an ecu problem or a mechanical problem. Im getting to the very end of the list of physical components it could be by now , really i want to check my rods are all good. horror stories of inaccurate test kits putting me off buying one for a one time use though

I even in a moment of anger today unbolted the exhaust and ripped it through the gears and obviously no different, still laggy in the powerband. just ringing ears lol.

I cant imagine another MAF will cure it, while it does restore overall power for a bit, its still got this 1-2 second delay where the revs slowly build up.

 

[Connor H]

Failing it being rods...- clutch, flywheel, those are the last mechanical things i can think of. And i have replaced both a 4 years ago!

 

[ExiledWeegie]

what about the throttle pedal? you can log its position and voltages in vcds, the pedal has 2 potentiometers that could be laggy or never reaching full throttle.
i got my compression tester from amazon, daygun or something, cheap and nasty for £25, it seemed to work fine, all cylinders were within a couple psi of each other.

 

[Connor H]

what about the throttle pedal? you can log its position and voltages in vcds, the pedal has 2 potentiometers that could be laggy or never reaching full throttle.
i got my compression tester from amazon, daygun or something, cheap and nasty for £25, it seemed to work fine, all cylinders were within a couple psi of each other.

I actually did check my pedal position and it was reading fine, flat was 100% or nearly. I logged my TB position during WOT too. i really have been to every corner possible with this sh*te lol.

I do appreciate the suggestions though, so if you have anymore keep them coming and ill keep checking. Ive spent enough money and time, i might as well give it some more thought.

 

[BadBoy03]

The only thing lurking round the corner is the scrap!

I feel your pain

 

[nd-photo.nl]

Hmm weird issue, the things Im thinking about:
-N249, any modifications like a bypass or n249 delete?
-What does your IATs look like?
-Did you check your intercooler? Maybe clogged?
-What DV are you running? Did you check if its holding vacuum?

 

[Connor H]

Hmm weird issue, the things Im thinking about:
-N249, any modifications like a bypass or n249 delete?
-What does your IATs look like?
-Did you check your intercooler? Maybe clogged?
-What DV are you running? Did you check if its holding vacuum?

n249 is mapped out, but it had the issue with it mapped in

IATs are good, on boost and idle all normal

DV is relatively new oem , tried a spare

havnt had the fmic off to check it, but im currently looking to scrap this leon and replace with another now

 

[nd-photo.nl]

Ah ok, see you in the MK3 forum soon then

 

[ExiledWeegie]

ive actually done some testing and found that at stage 2 map im only making 163.9g/s at wot which equates to around 205bhp, and i instantly thought of this problem you have, ive checked everything for leaks and checked the map for fueling and everything seems spot on, for all my mods i should be making 240bhp easily.

so ive done some digging and for the last year or two ive had a cold start rattle from what i thought was the chain tensioner which i replaced with a gates part and it still rattles slightly on the cold starts so i just put it down to the oil draining overnight but.... i had my rocker cover off and theres a slight marking on it from the chain slapping against it which must be happening when cold and is what im hearing, it never does it warm and once the initial noise happens it doesnt happen again until the next day. so checking vcds i think it was block 93, it shows i have 6 degree of retardation which means my chain has stretched quite a bit, as far as i can make out 0-2 means new or light wear, 3-5 means worn, and 6 onwards means badly worn.

this bit some might not agree with but with the help of ai and its explanation i think the -6 degree of retardation is causing the intake valves to open slightly too late meaning the air is slightly mistimed in the combustion process and the ecu is dumping timing and boost as a result. both the exhaust and intake valves need to overlap slightly when opening so that the exhaust can scavenge air out and the intake can pull a massive amount of air in which will obviously show on the maf readings as a much higher amount if being drawn past it.

dont quote me on the ai part here as im not 100%, its sounds reasonable though and i'll be the guinea pig, im going to change my chain and tensioner tomorrow for a febi kit ive had for a month or two but never got round to it so i will be back to let you know. what you could check though is if you have vcds check the chain stretch in block 93, if your at -6 or more then it might be why your seeing the same problem?

sorry for long post.

 

[ExiledWeegie]

How to Check Phase Position via VCDS

1. Start the engine and let it idle until it reaches a full operating temperature of 80°C–90°C.
2. Connect your diagnostic interface and open the VCDS software.
3. Click on Select Control Module -> Go to 01 - Engine.
4. Click on Meas. Blocks - 08 on the right side.
5. Type 093 into the Group box and click Go!.
6. Look at Field 3 (labeled as Phase Position or Camshaft Adaptation). [1, 2, 3, 4, 5]

Reading the Results for the AUQ Engine

• Ideal Spec: A perfect reading is 0°KW. The official acceptable factory specification tolerance is between -3°KW and +3°KW. [1, 2]
• Stretched/Worn Chain Warning: If your value drifts significantly into the negative range (e.g., -6°KW to -9°KW or lower), it means the intake camshaft timing is retarded. This is usually caused by a stretched cam chain or severely worn plastic shoes on the cam chain tensioner. [1, 2]