[andygibson]

Please help me as my head is about to explode. I've very recently changed the mani/cat on my 2001 y-plate 1.8 vectra (ecotec). also the lambda sensor. the car now has started misfiring on cylinder 4 only. this has been confirmed with diagnostics with no other faults showing. Started with changing the plugs, followed by the coilpack a different lambda sensor, Can took it to a top mechanic this morning who checked cylinder compressions, injectors, air inlet manifold etc..................all ok?? Can anybody help me?:shame::shame::shame::shame::shame:

 

[erroneusbogz]

have you got a duff plug,swap them around?

 

[HandyAndy-UK]

Try swapping the 3 and 4 plug leads over (both ends) and see if the misfire shifts to the 3 cyl.
And as a follow-on from what erroneousbogz said, move the 4 plug to a different cylinder, check it for hairline cracks, clean the entirety of the plug and lead.
I'm thinking possible breakdown of the lead or contamination allowing random shorting.

 

[andygibson]

Cheers Guys, but i've definately illiminated plug and problems with the coild pack as i've replaced both this morning before getting compression checked.

 

[HandyAndy-UK]

By eliminated plug do you mean plug leads as well ?

 

[andygibson]

doesn't have plug leads, just the coilpack which i've replaced, the wiring that comes from the plug that goes into the coilpack, is i assume ok as it is protected, is that wiring something that would give you problems???

 

[HandyAndy-UK]

Ok ... I only got a Vectra last week .... I'm still working out the CD70 :-(

 

[HandyAndy-UK]

Just having a read through the Haynes on it (ok, should have done that before suggesting plug leads), how about a damaged lead going to the ignition module ?

 

[andygibson]

can you point me in the direction of the ignition module

 

[HandyAndy-UK]

The ignition module is the long black strip that sits on top of, and plugs onto the sparkplugs. At one end is the lead connecting it to the ECU. If you are certain the plugs are ok and the ignition module, that lead appears to be the next most fragile part of the system - although Mr Haynes seems to favour an ECU fault.

 

[andygibson]

yes everything was replaced, as for the plug that connects to it, the wiring goes into no mans land as far as i'm concerned, thinking of having a look at the inlet manifold gasket to see if there are any cracks letting in too much air into cylinder 4, i've been told it was a fault on cavaliers. What do you think?

 

[HandyAndy-UK]

Possible I spose, but I have to admit to being a total novice on these engines and their predecessors in Cavaliers.
I've recently changed from a 3.0 V6 Omega to a 3.2 V6 Vectra. Before that I went through a pair of 3.0 Senators - my first thought would be you're missing 2 cylinders

 

[bennymac36]

its a good tip to use a piece of garden hose like a stethoscope and probe around the manifold listening for air leaking.

 

[steeltips]

I have a similar problem on a Zafira 1.6 16 v mar 2003
i have replaced so far a coil pack the plugs and an injector.

its been to a vauxhall dealer who read the codes and wanted to strip the engine head down and reseat the valves at £500 i told them where to go

at this point im looking at the ecu as the fault. but cant find it on the dam car.( anybody help there) i want to strip / open it and see if there is anything that could be repaired.

i would be interested in knowing how you get on

this may help
http://www.vauxhallownersnetwork.co.uk/showthread.php?p=2066586#post2066586