Cupra feels sluggish

[Tombles]

Hi guys,

I am not mechanically minded so wondering if some of you guys could offer help. I know there are a few of you who use and tune the 1.8T engine that i have in my cupra.

I can hear the turbo when i put my foot down but it just doesn't feel as fast as it should and there is not much of a kick to it and after around 5000rpm it feels quite flat. The car as i know is completely stock. It's a facelift 2003 Cupra.

What would be the best way to check if it is not putting down the power it should? Take it on a RR and see what the figures come out like or is there another way?

I don't have vagcom so can't check for faults. Someone mentioned the MAF sensor but i have no idea myself.

Thanks

 

[Gaygle]

Could a split/leaking hose be causing this?

 

[ethos]

Unplug the maf sensor and see if it runs the same, if it does... the maf sensor is probably at fault.

 

[Firestar_3x]

Few questions to ask:

- Can you hear pressurised air when you put your foot down?

- Any lights on the dash?

Problem is it could be many things, might be the MAF, could be a bad AFR reading and adaption setting stored in the ECU, could be a bad batch of fuel, might be the MAP sensor, could be a boost leak, could be the plugs have gone bad.

With these engines the list goes on and on.

MAF sensor disconnect is a good shout.

 

[Tombles]

Thanks guys, heard about unplugging the MAF sensor so will give that a shot and see.

Firestar - when i put my foot down i hear the whistle like air noise then when i take my foot off i hear the 'tshh' noise. Not a great explanation but hope that helps.

 

[paradigm]

I'd check all hoses for air/vac leaks, check all the connections to the TIP, intake manifold, and the N249 valve.

Where are you based?

 

[Firestar_3x]

Thanks guys, heard about unplugging the MAF sensor so will give that a shot and see.

Firestar - when i put my foot down i hear the whistle like air noise then when i take my foot off i hear the 'tshh' noise. Not a great explanation but hope that helps.

Could be the Diverter Valve has gone bad and is leaking air back into the intake.

You can test the valve by taking it off, pushing the piston up holding your thumb over the vac nipple and the piston should not drop all the way back down.

 

[Virdi]

With the hot weather lately - Believe it or not, this does affect Turbo cars big time.

First thing is - Get it on VAGCOM.... I was once down on power due to the front Lambda Sensor playing up.

 

[paradigm]

With the hot weather lately - Believe it or not, this does affect Turbo cars big time.

It isn't that hot dude. Yeah if we were up in the top 20's I'd agree, but we aren't.

Yes the hot weather can cause a reduction in air intake, but not that drastically that you'd notice when the outside temp is 15-22~

 

[Tombles]

I'm based in Hertfordshire. Wouldn't mind taking it somewhere to check it out but don't really know any good garages in the area who i would trust.

Cheers for the help Para and Firestar but as i said i am not mechanically minded and wouldn't be sure how to check those things out correctly.

 

[Adam]

My MAF sensor broke on my LCR.

If you remove the sensor and go for a drive you'll be able to tell if it is faulty. The engine management light will come on for a brief time, but if the car performs normally you can be reasonably sure the MAF sensor is at fault.

Cheapest place was Euro Car Parts at around £60 (after handing the faulty part back)

 

[paradigm]

Cheers for the help Para and Firestar but as i said i am not mechanically minded and wouldn't be sure how to check those things out correctly.

Basically, follow all the rubber pipework from the air filter, and anything that comes off the TIP (turbo intake pipe - the one that goes from the filter box, through the MAF down to the turbo). Make sure that your N75 valve (electrical thing near the top of the TIP is still plugged in), and your N249 valve (on top of the engine under the plastic cover) is plugged in also, its easy to spot as it has a whole mess of 8mm pipework connected to it.

Your diverter valve is the large cylindrical black plastic thing, about half way up the TIP, it has three pipe connectors, two that are around 35mm, and one that is a 6mm pipe. Disconnect these, and see if the piston inside (push thumb up from the bottom hole) moves freely, then do what firestar suggested, which is to push the piston up, and place your finger over the top hole (the small 6mm one) to test if the valve is still pressure tight.

Also check the pipework connected to the throttle body, and the intake manifold (these are at the front of the engine, both attached to each other), the intake manifold is the large silver thing, and the throttle body is the peice on the end of the manifold, between the rubber hose and the manifold itself. These pipes have a habit of splitting or working loose.

 

[Tombles]

Thanks Para, that should be easy enough to follow. At work at the moment but will give it a go when i have some free time. Cheers

 

[gobbo]

Agree with others, sounds like a boost leak or dodgy MAF to me

 

[Virdi]

Buy a cheapy VAGCOM USB lead from fleaBay and check it yourself

The basic VAGCOM software is free.

or

Get onto SEATCUPRA.NET forums and see if anyone local to you has VAGCOM.

 

[Gaijin]

Sounds silly, but are you running on Super Unleaded? My mates car ran like a dog until we found out he was putting normal UL in it, and bunged some SUL in it.

However, it was a knackered Rover 620ti

 

[Virdi]

ok - Here's a little guide that someone done for me a while ago

MAF = Mass Air Flow Meter (It lives between the air box and the TIP - Turbo Intake Pipe). I think it measure the temperature / density / air flow coming into the vehicle). A mass airflow sensor is used to determine the mass of air entering the engine. The air mass information is necessary to calculate and deliver the correct fuel mass to the engine.

The N75 is the boost Control Valve (I believe), and this sits on the TIP behind the MAF (see below) - the electronic boost controller allows the turbos to spool up a little faster. A wastegate might be designed to open at 7PSI, but it usually cracks open a little even before the pressure hits 7PSI. This will slow down spoolup of the turbo, causing it to hit 7PSI a little later. A good electronic boost controller would keep the wastegate shut for as long as possible, by using the solenoid to connect the wastegate to the atmosphere (0PSI) till the turbo gets really close to hitting the boost you want, only then it will start switching the solenoid back and forth according to the duty cycle. To determine how long to keep the wastegate shut, most electronic boost controllers use a number known as GAIN. If the gain is set too high, the boost could spike (the wastegate is held closed a little too long causing overboost), but if the gain is set too low, the spoolup is not as optimal as it could be. Getting the correct gain setting will give the optimal spoolup of your turbos.

The Dump Valve sits behind the N75 valve, and its primary function is to regulate any excess boost (see below).
Dump valves are fitted to the engines of (usually older) turbo charged cars and sit between the turbo outlet and the throttle body. When transitioning from a boosted state to a closed throttle state (as in between shifts), due to inertia, the turbo continues to pressurize air, but the closed throttle prevents the compressed air from entering the engine. In this case the pressure exceeds the preset spring pressure in the dump valve and the excess pressure is bled off to atmosphere.

 

[Tombles]

Thanks for the guide, that will be very useful

I will try and see if anyone near me has vagcom on seatcupra.net and if not i may purchase the lead. Thought it would be more expensive than it is.

Oh and yes i do use Super Unleaded

 

[HamZilla]

I'm based in Hertfordshire. Wouldn't mind taking it somewhere to check it out but don't really know any good garages in the area who i would trust.

Hi Tombles,
I'm in Watford and I also have a Cupra, and a VAG Com cable from ebay.
The only thing I don't have is a laptop but if you can bring one with you we could have a go at looking at whats wrong.

 

[Tombles]

Hi Tombles,
I'm in Watford and I also have a Cupra, and a VAG Com cable from ebay.
The only thing I don't have is a laptop but if you can bring one with you we could have a go at looking at whats wrong.

Thanks for the offer Ham but i just ordered the cable for myself which should be here tomorrow hopefully