Holden Commodore Problems

Your friend is basically correct, the Gen III V8 is calibrated to run on ULP, and running it on PULP would produce only a small improvement. Overfilling some engines with oil can lead to damage, but in the case of the Gen III it seems there is no danger. It should only be done as an added precaution on engines that do consume oil, and I wouldn't follow the practice if your engine isn't devouring oil. You sound like someone who keeps a close check on the oil level, so I would recommend you fill it to the correct mark and keep monitoring the level. The number of problem engines is quite small, Holden says it is less than 2 per cent of V8s, so I wouldn't be concerned unless your engine is actually using oil. The fix implemented by Holden from the start of VY has done the trick, according to engine rebuilders.

I would definitely dispute the need to do anything in this case. You should be able to detect a blocked injector. The engine should run a little rougher at idle and under load, but if it's not, I would suggest there is nothing wrong. The fuel consumption numbers you quote are in line with what I would expect from a VX II Commodore V6.

I have never tested any of these devices so I can't offer an opinion other than that I am sceptical of claims made for them. Others who have tried them might be able to provide information. If you have, send your comments to grah.smith@bigpond.com

We checked with Peter Schweighofer of Swift Automotive in Melbourne who recommends the HM headers and exhaust system. If your car is an auto, he also recommends you have the shift pattern altered to make it sharper.

Like you, Mick, I can't explain why the acceleration figures for the supercharged Commodore should be shown as similar to the non-blown car. It doesn't stand to reason. The figures shown on Holden's website are not Holden's own performance numbers. They are taken from a comparison test done by other people. Holden doesn't publish official performance data. The numbers I have suggest that the correct 0-100km/h acceleration number for the normal V6 is about 9.2 sec and the supercharged car gets the job done in about 7.5 sec.

Thanks Matt. I'm sure Virginia will be keen to check it out.

Your Falcon would have tested about 13 litres/ 100km when new. For comparison purposes, the Commodore V6 would return about 11.5 litres/100km, the 3.5-litre V6 Magna about 10.5 and the Camry closer to 13. Clearly, on that basis the Magna is the car for you.

You really need to have it checked by a mechanic. It could be oil being sucked into the engine past the valve stem seals and burnt, or it could be running very rich. If it is the latter it could be because of a malfunctioning oxygen sensors in the exhaust or the engine temperature sensor, telling the computer the engine is running lean or it's not up to working temperature, and forcing the computer to pour more fuel in.

I'm not aware of any Commodore clubs. There is a club for fans of Holdens from 1960 to 1980 which would cover your Commodore. Contact them on 0412 914 345. Alternatively, contact the Association of Motoring Clubs on 9555 0133.

You've done just about everything possible and seemingly without finding the cause of the problem. The Commodore of that era is prone to driveshaft vibrations. I would suggest you have the driveshaft angles checked as that is often a source of problems like you describe. It is almost certainly a drive-line problem.