Vz Misfire!

[baracuda]

well found out what my problem is. need a new ECU.

 

[christo]

Thanks for all the replies, the VZ is finally fixed! I eventually gave up and took it to Ultratune, coil pack #2 was dodgy and they replaced it. Runs perfectly again!

$132 for the replacement coil, $130 for labour and $60 for a new metal inlet gasket. So about $320 all in, not a bad result I guess (Holden quoted me $195 for just the coil!)

Now I hope the other 5 hold out........

 

[mattsv6]

hey mate,

If another one fails, buy these and ill show you how to replace them all yourself without needing a new gasket. Total cost = $225 for 6 new coils.

GENUINE HOLDEN COMMODORE VZ V6 BOSCH COILS 3.6L - eBay, Other, Car Parts, Accessories, Cars, Bikes, Boats. (end time 15-Apr-10 13:27:26 AEST)

 

[Trent L]

Yep. Just picked half a dozen coils from the same Seller, together with a set of Bosch Platin plugs and a pair of front O2 sensors.

That should give my VZ a tickle up & help with the fuel consumption.

Just got to grab the metal inlet gasket for a VE and figure out how to fit 'em up.

 

[floody]

My Experience:

Stage One: Bought the car, on the way home I gave it a bit of stick up a hill and the powertrain warning light came on and the engine started misfiring. Pulled over, turned it off and an again, fault cleared, drove home.
I bought a ELM327 wireless adapter for my iPad ($30 generic brand off ebay) and downloaded DashCommand....this allowed me to read and clear the car's codes and confirmed my suspicions that it was a misfire (Codes: P0300 to P0306). Once the code had been cleared once with the iPad the car never misfired under load again.

Got the car serviced including a coolant leak repair.

Stage Two: after getting the car back from its service I could feel it 'buck' from time to time while idling. I took it back to the mechanics and they reset the computer to the allow the car to re-learn its fuel-air mixtures....this made it happy for about 30km but then it went back to its old ways.

Stage Three: About 150km after the service the car went into full time misfire, felt like I was driving a truck. Fault codes indicated misfire.

The Fix: While the car was running I removed each of the wiring harnesses from the coil packs and took note of the engine's behavior. One of the six coil packs produced no change in engine behavior when it was disconnected. I then replaced the spark plug in this cylinder and swapped the coil pack with the opposing cyclinder's and ran the same disconnection test again. Surprise Surprise the fault followed the coil pack. I then replaced the coil pack with an aftermarket part from AutoPro for $75 and the fault went away. I've only done 5km driving since but the car appears to run perfectly. I suspect the coolant leak previously mentioned had breached the faulty coil pack and corroded it to the point of failure.

Manifold Removal: I was lucky in that my faulty coil pack was on the rear cylinder, these coil packs are accessible. If your fault is one of the four forward cylinders you will have to raise the upper intake manifold (plenum). If this is the first time your car has had its upper intake manifold removed you will need to buy new gaskets as the factory ones are plastic and will tear. If you've already got a steal gasket set installed you need only to raise the plenum by undoing the 6 bolts on top and putting some wooden chocks under it....unplugging any hoses is unnecessary.

Putting it back together:
Spark Plugs: 16-20Nm
Coil Pack anchor: 7-11Nm
Upper Intake Manifold Bolts: 23Nm

 

[thevman]

Thanks for the awesome advice floody. Very helpful

 

[Damsix420]

so if I take the manifold cover off and it's got stock gaskets I'll have to replace the gasket? my cars done 289,000kms so I'm guessing it would've been replaced by now?