lumpy idle

[pegliobaglio]

When my car is sittin at idle the revs bounce between 500 and 1000 revs I have a tectom rev stavilizer but don't know what state of tune the engine is in yet as where I bought it from didn't know too much about it and I still haven't had the time to get it on the rollers yet,any ideas what would cause lumpy idle like that? Cheers guys

 

[Toby]

Whats changed on the car since it started (or has it done it since you're ownership)

 

[pegliobaglio]

Its done it since I have had it mate,I have only been doing chassis upgrades on the car so far other than a forge recirc which has been on the car a good 6 months

 

[RyanH]

Could be a tiny boost leak somewhere, like a vacuum hose has come off or split. Had this with a couple of mates cars.

 

[pegliobaglio]

Cool man cheers,would a boost leak cause the turbo to sound louder? Ie I can hear it spinning up louder than it was before

 

[Toby]

There is a tiny breather hose, only about 8cm long, goes from the end of the fuel rail to the underside of the inlet manifold.

I forgot to put this on when i rebuilt my engine and the idle was terrible.

 

[pegliobaglio]

Cheers dude will check that also !

 

[Jay]

+1 to the boost leak as i had the exact same prob just before JAE. turns out it was the intercooler hardpipe connection behind the front bumper. the other thing that it could be (and i would look at this last, boost leaks first) is a faulty o2 sensor. are you using excessive amounts of fuel? when i got my 15 the o2 sensor was dead and i was getting only 220 miles to a full tank of fuel, plus the lumpy idle. i got the car mapped and my mapper worked around the sensor, now i get 330miles to the tank.

if you are getting alot of turbo noise then the obvious thing to check is the turbo gaskets. sr20's are famous for killing those gaskets! that would kill both problems at once if its knackered

 

[pegliobaglio]

Cheers buddy,does seem to be using more fuel too,will have to check all of the above then.
What the best- easiest way to check for boost leak?

 

[Jay]

good luck sorting this, i know how irritating it is to have tickover issues!! :thumbs:

 

[Jay]

i got a mate to do it. most good garages will be able to pressure test your system. you have to disconnect and block off various pipework, then pressurise the system with a generator. my mate is a senior mechanic for audi and runs a s14 so knows the engine backwards. me? aint got a clue lol

 

[pegliobaglio]

Cheers mate,its going in end of the month for mot and a few other bits so If I don't have it sorted by then I am sure they will sort it out for me