Weird Astra Mark 4 problem.

[The Reverend Bluejeans]

Weird one this. W plate Astra 1.6 which idles on three pots - well, maybe 3.5 but certainly not all four. Revs up okay on four but feels flat and lifeless. They're no rocketship but they're normally reasonably brisk.

It does burn oil and puffs a bit of smoke (a bit, not a big cloud) when revved. Compressions are all a strong 190psi on all four. Plugs are okay, coil pack delivers a good spark. The EGR valve seems to be okay as it was replaced a while ago. I know sod all about these, a bit new shape and modern for me. Any ideas?

[Cavcraft]

I'd try other 'known good' plugs for a start. Failing that the IACV and the throttle body are favourites too. The latter is a little tricky to remove (back of engine underneath the scuttle panel) but both will clean up with choke and carb cleaner.

Don't discount the EGR though, it could be duff and I think you can unplug them and the car will still run so perhaps try that first and see what happens as it's a no cost trial.

 

I'm assuming it's a 16V by the way? I found the 8V models seem quite sluggish in comparison.

[The Reverend Bluejeans]

Yes, she's an Ecotech.It's also a multipoint one (2000 onwards?) with the fuel rail and 4 injectors if that makes any difference? The EGR was disconnected and made no difference, neither did plugs. It's basically a shitty idle and no real power. It won't pass the forthcoming MOT with the idle so poor - a definite 'putt-putt-putt' from thje tailpipe as well.

 

Surprising lack of rust on it - anywhere. Not a bad little tram these. I'd suffer one.

[Cavcraft]

Bad idle would lead me to think IACV. Never changed one myself but I believe it's a straight forward job. www.vxon.co.uk probably a good place to look, plenty of help on there and I bet there's a 'sticky' on this problem.

 

I will just add I'm not certain that the IACV would lead it to run a bit flat, but I'll do some fishing and see if I can find anything out.

[The Reverend Bluejeans]

Lovely job, thanks!

[Cavcraft]

'Common faults on these are sticking valves, air intake leaks, fouled plugs, bottom pulley not aligned correctly leading to timing issues, coolant temp sensors (mine ran like a dog when my CTS went) oh and collapsed cats / blocked exhausts'

 

The above courtesy of a kind gent on Migweb.

[M'coli]

Just as an easy elimination thing, is it misfiring on the cylinder closest to the servo vacuum hose?

[The Reverend Bluejeans]

Just as an easy elimination thing, is it misfiring on the cylinder closest to the servo vacuum hose?

 

Number 2 plug was a bit oily, but not a catastrophe. Well, unless the oil control ring has gone on that pot in which case, it's curtains for the poor thing. A sticking valve was ruled out by the compression test.

CTS/bottom pulley are worth a look. Ta!