MK5 Golf GTI

All Things Mk5 => How to Guides / Troubleshooting => Topic started by: maxamplitude10 on March 05, 2021, 06:50:30 pm

Title: Engine splutters when brakes pumped?
Post by: maxamplitude10 on March 05, 2021, 06:50:30 pm

Guys I've just noticed that when I pump the brakes the engine stutters and farts, I assume this is some kind of vac leak but is there a non return valve somewhere in the circuit which could be at fault?

Any direction/ ideas would be very much appreciated

Max

Title: Re: Engine splutters when brakes pumped?
Post by: pudding on March 05, 2021, 08:19:18 pm

Yeah there's 2.  One in the vacuum pump to intake hose, and another one in the hose that runs around the back of the engine to the firewall.

I have to say though, if you're stabbing at the brake pedal with the engine idling, it's not unusual for the engine to stutter as it's emptying the servo and heavily loading the intake manifold/vac pump.  If you had a genuine air leak, the long and short term fuel trims would be huge and the brake pedal would need a heftier shove than normal.

Can you hear a hissing noise at idle that goes when you press the brake pedal?  If yes, the brake servo is f'cked.  Quite common and mine's been leaking for years, but haven't got around to changing it.

Title: Re: Engine splutters when brakes pumped?
Post by: maxamplitude10 on March 05, 2021, 10:09:54 pm

Thanks Pudding yeah I think you may be correct as I was stabbing at the pedal checking on brake pressure sensor fault :happy2:

Cant hear any hissing at idle either....

Cheers Max