rough idle / revs all over

[bigj1976]

hi, my seat leon 1.6s on a 55 plate has recently decided to rev wildly it goes up to around 1200 rpm then down to about 6/700 rpm and seems ready to cut out then up to 1200/1300 again . also now revs itself and accelerator does nothing and cutting out when driving .

ive got the free vcds software and connected it up and got
17961 barometric /manifold pressure signal implausible correlation
17912 leak detected.

any help would be greatly appreciated .

 

[mty12345]

I would guess at a big air leak somewhere in the system mate, that's what 17912 comes back as and would probably cause code 17961 as well. 17961 is related to the readings from the MAP sensor, so if there is a big leak then the reading would be wrong compared to what it's expecting to see.

 

[bigj1976]

I've just been out in it and it's virtually undriveable, surging and cutting out . any idea for usual air leak candidates ? cheers .

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[mty12345]

I'm not familiar with the 1.6 engines, but if you follow the intake pipework from the airbox to the manifold then it'll probably be a pipe come loose if it's that bad. Either that or a big leak in the vacuum system somewhere.

 

[bigj1976]

my 1.6 has the engine cover/airbox in one . so there's no pipes to inlet manifold

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[Calumcjm]

Best thing to do would be to do a pressure test from the air intake to the tb? Just throwing an idea out there

 

[mty12345]

Best thing to do would be to do a pressure test from the air intake to the tb? Just throwing an idea out there

Yeah i agree, smoke/pressure test would reveal any leaks.

 

[mty12345]

my 1.6 has the engine cover/airbox in one . so there's no pipes to inlet manifold

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In that case i would guess it must be a leak in the vacuum system. If not then i guess a faulty EGR valve could mimic a leak, although i would of thought you'd get a code for it.

Possible it could be the MAP sensor itself, although the reving and hunting would definitely make me lean towards a air leak as the cause.