Help.

[MAZ1.8T]

We have a 1.8t cupra AUQ engine. FSH un molstered. Cambelt waterpump recent. New lamba sensors last year.

Developed a misfire when cold warmed up would vanish drive superb.

So we changed the plugs and all 4 coil packs. Misfire gone but idle feels lumpy sounds roughish still suggestions

Goes up 1200 rpm drops 1000 then goes all rough drops to 800 no issues.

No EML

 

[cupra r. ash]

Try unpluggin you maf mate and see how it runs, if it runs better then its you maf, or you myt have a small boost leak, try your dv to chargepipe hose

 

[MAZ1.8T]

so unplug MAF if its nice and steady change MAF, no difference look for leaks?

 

[Allan_84]

yes you can try running with out the maf.
other thinks it could be: boost/vacum leak, and you could do a throttle body alignemt/reset with vagcom.

 

[MAZ1.8T]

stab in the dark MAF only cause turbo boosting ok pulls like a train. Ill check and update ya all.

Suggestions for new MAF and boost pipe

 

[rk696]

Could also be a bad coolant temp sensor. Does it run lumpy only when it's cold? When the sensor fails, the ECU thinks the engine is warm, so it runs like sh*t until it warms up, then it's fine.

p.s. It won't affect your temperature gauge on the dashboard either. Ideally you need vagcom to see if it's storing any fault codes, or to check the sensors and do a throttle body reset etc.

 

[MAZ1.8T]

i dont have a VAG Com but we are in barnsley

 

[rk696]

I'm not too far from you mate, and I have vagcom

 

[MAZ1.8T]

thats what i wer thinking lol

 

[MAZ1.8T]

is that sensor easy to change like?

 

[rk696]

Yep, 2 minute job once the engine has cooled down. Can't fo it hot, as the water will spary out everywhere.

 

[MAZ1.8T]

used to astras previously= when you free?

 

[MAZ1.8T]

it screws into top of coolant bottle IIRC on most cars?

 

[rk696]

On the 1.8t it clips into one of the coolant hoses down the side of the engine.

I'm free next wednesday if its any use. Workin until then.

 

[MAZ1.8T]

if i cant get to bottom of it ill take u up on offer wers best place to get VAG COM and does it work with canbus?

 

[rk696]

You can get the leads off ebay, and then get the free version of vagcom, called VCDS lite. It only allows you to do basic stuff though, and clear fault codes etc. I have a full (old) version of vagcom and I can do logging etc on it.

Don't need canbus for your car, you need what's called a hex interface iirc.

 

[MAZ1.8T]

ta mate

 

[MAZ1.8T]

so what test function do i carry out on VCDS LITE

 

[rk696]

It has what are called measuring blocks. These show you what the various sensors and stuff are doing. You can look at block 004 which will show you what temperature the coolant and air inlet temperature sensors are reading. If they're showing a stupid value, you know they have failed. You can check pretty much every sensor with measuring blocks. VCDS lite only has limited capability in measuring blocks, so you might not be able to read what you need to.

You can also look for any stored fault codes, and do a throttle adaptation (calibrates the throttle pedal to the throttle bosy and teaches the ECU where full throttle and idle etc are).

 

[STdemoniac]

i have problem with my cupra 180hp, sometimes lose power betwen 2000-3000rpm, and bad working on low idle...

and after change one small plastic valve (cheap), couple vacuum pipe, and MAF problem sorted

p.s. folow forum rulles i can`t post images (url) at this moment, but try to paste this link in to ur browser, just add on the front: "h t t p: / /" (without space`s)

i571.photobucket.com/albums/ss159/STdemoniac/SEAT%20LEON%20CUPRA/IMAG0195.jpg

i571.photobucket.com/albums/ss159/STdemoniac/SEAT%20LEON%20CUPRA/IMAG0207.jpg


if this valve not working, then have air boost leak, but not outside, like ex. ic or hose broken and air leak outside, in this situation air leak inside motor block , and hard to find problem, why lot of audi, vw seat, 1.8T cars have same problem, and new MAF, coil, lamba, spark plugs and many other things can`t help