MOT emission issue, revving engine on its own

[Dai_O]

Hi Guys

I am driving a 1.6 Seat Altea XL petrol 2007

Just had an MOT done this week, all went really well until we got to the emissions test

The inspector put his adjustable bar from the steering wheel to the accelerator and adjusted it so it was pressing on the pedal to give a steady 2500rpm to carry out his tests

All fine so far, then after about 20 seconds the car pick the revs up to 5000 rpm on its own, the increase from 2500 to 5000 happened in a matter of seconds,

He slackened off the bar but it did the same 3 or 4 times which made checking the emissions impossible as he said he needed a 1 or 2 minute steady rpm to check them.

On the fifth attempt it did remain at 2500 rpm and all was good with my emissions. he passed the car but he said I may want to look into this.

Question what the hell is going on there, I got home and tried it, held my size 12 steady on the accelerator and it was fine for 20 seconds but then it increased as in the MOT station to approx. 5000 rpm, it was still climbing when I took my foot of the pedal!!!!!

The only other observation he made was a small hissing noise from the engine bay, he said it sounded more like air being sucked in rather than being pushed out, His suggestion was to get a can of easy start and spray it around to see if I could get the engine to rev, apparently the introduction of easy start would make the engine rev.

I took a picture of the area it sounds like it is coming from, somewhere in that red box lol

https://drive.google.com/file/d/0B6izbAo2JZjkQWk0dkZCbTlCT00/edit?usp=sharing

Would the use of easy start be okay, some people say this can cause issues??????

The MOT tester said it could be this air leak or a problem with the TPS (throttle position sensor), I have a copy of VAGCOM, is there any way to test the TPS using vagcom

Thanks for your time guys

Dai O
Cardiff

 

[drummer.gavin]

My understanding of Easy-Start is that engines almost get addicted to it. Fine if your trying to start an old tractor but not a modern car that you would like to get years out of it. I'd not use it.

It nearly sounds like it's running away with out the explosion. Would it be a MAF problem?

 

[Dai_O]

Cheers drummer

One other thing I have noticed is the engine temperature gets to 90C very quickly.
This morning it was 14C outside, the car had been parked all night, I only drove 1mile and the temperature was at 90C, in that 1 mile I DID NOT stop once, and was only travelling about 30 - 40 mph

The car sometimes smells hot, if that makes sense, some times when I get out and walk past the front end you have a whiff off that hot smell. but the engine temperature never gets over 90C

Somebody mentioned a breather could be blocked?????

Will get the VAGCOM out tonight to see if there any codes in there, I have no lights on the dash

Thanks again for looking dudes


Dai O

 

[drummer.gavin]

Cheers drummer

One other thing I have noticed is the engine temperature gets to 90C very quickly.
This morning it was 14C outside, the car had been parked all night, I only drove 1mile and the temperature was at 90C, in that 1 mile I DID NOT stop once, and was only travelling about 30 - 40 mph

The car sometimes smells hot, if that makes sense, some times when I get out and walk past the front end you have a whiff off that hot smell. but the engine temperature never gets over 90C

Somebody mentioned a breather could be blocked?????

Will get the VAGCOM out tonight to see if there any codes in there, I have no lights on the dash

Thanks again for looking dudes


Dai O

Coolant level ok and are the fans kicking in?

 

[James_R]

It's perfectly normal behaviour for these types of engines.

 

[Adam4D]

Tell your tester to stop being so lazy and to use his foot to hold the revs and keep it steady

 

[kblackburn]

If it was an air leak, it would show when doing the emissions test.

 

[WhatsGoingOn]

take it to SEAT dude

 

[James_R]

It's perfectly normal behaviour for these types of engines.

I'll just repeat myself incase you missed it.

BSE engine will flag the eml if there was an air leak.

The 1.6 8v and 1.4tsi engines both have a habit of raising the revs when you try to hold them.

 

[Dai_O]

Cheers MJ, thanks for your input, will close the bonnet and leave it lol

 

[James_R]

Might be worth nothing they're a relatively trouble free engine too