flat spot - I've tried all sorts - any more ideas???

[toptotz]

I have a terrible flat spot on one of my cupra R's - I've tried all sorts to fix it but am at my wits end!

so far i've had the following done but to no avail:


New Boost Controller Sensor,
New Mass Air Flow Meter,
New Platinum Plugs,
also had it remapped to see if that would cure it but it hasn't - i've even had the map done twice to double check!!!

It's been linked up to see if there are any faults showing & it is showing no faults at all...

Please can anyone help as this is turning into a very expensive cure!

 

[robreidmotors]

Whatever air filter you have check its clean.
Check all vacuum pipes, air pipes, breather hoses very very closely for cracks or splits where they connect and along them.
With engine running listen for air leaks/suction around the engine, you can spray wd40 around various places listen for a change of engine sound which will hint at a leak.

My favourite though would be to give the throttle body a good clean out with throttle body cleaner, cured my flat spots. Also check all electrical connectors and give any bad contacts a good clean.

After all that some kind of fuel cleaner is useful to run through. Ones i find very good are stp, forte and red line s-1 or 2.

As there are no fault codes i think a good old fashioned approach as above could help.

 

[toptotz]

ok - thanks for that, i hadn't even thought of possibility of a split hose or something although it has had a full set of silicone hoses fitted which hasn't cured it either, is there any particular hoses other than these which would make a difference? i'll take a trip to halfords today for some additives & get my head under the bonnet when it's dry next!

 

[robreidmotors]

I always use fuel cleaner as the last thing, when all else seems to be working, that way I think you get the best out of it.

I dont know much about turbos, but obviously aside from the usual ignition and air filter stuff ive mentioned, it looks like its very important that all hoses are okay.

Basically check all of them, especially the small ones, vacuum hoses etc, they can be really difficult to spot a crack or split so take your time, gently twist them. I found a crack on one of mine after about the seventh attempt checking round the engine.

I think cleaning the throttle body could help, makes a big difference. Tends to get a little oily/gummed up in there which can cause similar issues.

 

[toptotz]

oops - i've gone for the easy fix first & added fuel cleaner, lol, also bought carb cleaner & gonna do my throttle body tomorrow if it's dry - unfortunately i own 2 of these, both on an 02 plate & they both have flat spots of varying degrees, i've added the fuel cleaner to the one that's not so noticeable & just beginning to show a slight flat spot (probably me being a bit picky due to experiencing the really nasty flat spot on the other) & it seems to be helping but i think the other is more serious & split hose or gunged throttle body could be favourite! unfortunately i don't have much experience under the bonnet (come on, most women can't change a wheel, lol) but with help from the peeps on here i've managed to seal my leaky doors on both cars & get into my lock on the boot of both to order necessary parts as neither boot will open either - talk about jinxed!

 

[robreidmotors]

There is also something called an 'italian tune up' which works well, but you have to trust your engine!

You warm the engine, then on the road take the revs to the red line in first for a couple of seconds, then same in second and so on.

It gets the engine hot and helps burn any carbon etc from the valves, chambers etc. But as i said you have to trust your engine as you are red lining it. Italian because its apparently what they used to do on ferraris etc.

 

[toptotz]

mmmm, my cambelts are due to be changed also so i'm not so sure... how fast am i gonna have to go to get it to red line in 5th or 6th? i quite like my driving licence & my cars!!!

 

[robreidmotors]

dont do it if you arent happy with it.

I did it today just in first and second, not even red line. my red line is six upwards but i held it at 5 for a few seconds quite a few times, seemed to help.

to be honest though a good tb clean and fuel cleaner should do the trick.

An O2 plate isnt that old, but i think tb clean and fuel cleaner should sort it.

Although ive mentioned it, check the air filter, if it hasnt been done per chance from new then it could be restricting air into the engine.