bigdel

I know it's a long shot, but are there any Vauxhall experst out there?
We've just bought a 1.4 Corsa and it has a bit of a lumpy idle and occasionally drops into limp mode whilst driving.
When it's not in limp mode it seems to drive fine, and the idle seems lumpier when its cold.
We have (somewhere) a Scanguage II, which I'm told should read the faults when it goes into limp mode, will this give us enough to go on to diagnose the fault?
Any common faults? I've read about MAF & O2 sensor problems
Also the aux belt snapped yesterday. I think its just old, and can't find any otehr reason for it snapping, all the pulleys etc seem to be free enough, but is there anything common to check for there before fitting a new belt?

oldford

What's the model-year of the car? 2000 or earlier? Then Scangauge doesn't work.
You could also check the engine code. If it starts with a "X" then Scangauge doesn't work. It will work if the engine code starts wit a "Z". There will only be fault codes if the engine management light is on or has been on not too long (roughly less than 30 motor starts) ago.

bigdel

It's a Z14XEP i think. It's a 2004 1.4 SRi

The scanguage doesn't pick any faults up and the engine management light doesn't come on.
It idles better when the aircon is ON, as we think the engine management must raise the idle level accordingly to compensate

london_chris

its usually the throttle body from memory, gets caked in shit and gums up the airway in the throttle body.
i think if its the model im thinking of just 4 torx bolts to the inlet manifold and remove it, armed with a can of carb cleaner and a thin screwdriver and wire brush.
may also be the egr valve if it has one, they can create unusual idle problems.

bigdel

throttle body's been cleaned out, but not egr valve yet. will dig around and see if we can a) find it, and b) take it off and clean it!!
Cheers for your help so far guys

mark826

Does this have the two breather hoses on the cam cover? These get really gummed up, block up then pretty much explode. Not sure if these would cause said fault however it's well worth while to remove them and have a look.

bigdel

yes, two hoses to the right of the throttle body. will check those too. cheers

bigdel

It's recently had a new (recon) head and a timing chain change, so we whipped the cam cover off and checked the cam timing. the exhaust cam was spot on, but the inlet cam was about 1/8th of a turn out. Corrected that and it seems to run a bit better, though still slightly lumpy. Still to check the EGR and throttle body, breathers were clear.