I have a VS commodore ute with a supercharged V6 out of a VT, the vehicle has a slight miss under full load at higher revs in full boost, could drive round normally without noticing but when the foot goes down it'll play up, spark plugs and spark plug leads have been replaced, just wondering if there are any other components that are known for failing that could cause this and are these engines known for 'pinging' on normal unleaded fuel
When you say mixing between PULP do you mean 95 or 98? By mixing octane ratings don't expect to get a full tank of 98 next time you fill up with 98. You'll probably need to run 3 full tanks of 98 before you get the full benefit of it. Try drain your tank as much as possible and go refill with 98. I think when you're booting it and running only 91 it's causing pinging and the knock sensors are kicking in. Anyone else agree? By the way I should ask, are you running higher boost than what came on the factory engine? If you are you'll definately need to run 98RON
na 91 and 95 its not often i change between them but 91 atm....i think we're on the money here it makes sence to be the knock sensors working but how harsh are they?will it pick up a knock everytime? will it cause a noticable miss? i know it'll retard the timing but yeah im not sure bout extent of these...might be worth trying a tank of 98 BTW: it has a terra charger pulley setup
If you have a Terra charger setup then I would assume it's at least a 10psi pulley (or 87mm)? In that case you're DEFINATELY going to need to be running 98! I don't know exactly to what extent the retarding will be but it can't be good.
tryed 98 fuel made hardly any, if not no difference...made sure it was almost dead empty before putting in the 98 and no luck. next thing i will be looking at is spark plug gap...as it wasnt me who put the plugs in im unsure on the gap so ill check them and then try maybe a 0.7mm gap any thoughts anyone??
Good fuel is a necessity, try a few tanks of BP or Mobil Synergy 8000 and see how it goes from there - remember that from factory they are recommended at least 95RON STANDARD so it is not a good idea to run any lower than that
The recommended spark plug gap for the s/c 6 is 1.1mm for Bosch plugs and 1.3mm if using NGK. This info is based on both companies catalogues. Look at both companies websites for exact part numbers. When was the last time the injectors were cleaned? Try a bottle of Nulon 'Total Fuel system Cleaner to a full tank. Or two bottles of Nulon Injector cleaner. Also are your sure you're running the correct leads for a s/c motor and not just the ECOTEC leads?
ok that im not sure of eather as i didnt fit them as well...what are the obvious difference? part numbers etc? as for the fuel it didnt make any difference really...the thing was near dead empty before i put in like i was driving round with the fuel light on for awhile before i put the 98 in and yeah i gave it a chance to pump the good stuff through and then yeah gave it a boot full and same problem
Next step would be to put in the correct spark plugs and a couple of bottles of fuel/injector cleaner. I Remember I had a similar problem with my first VS with a N/A ecotec. When I'd put the boot in or even just accelerate to overtake it would cough and splutter. Turned out to be a faulty lead. But then again you said you changed yours. :unsure: I'm not sure how different they are compared to the ecotec but look for a part number if you can.
You need to run a few tanks to get rid of all the old 91 octane. You will not see gains straight away, give it time and keep using the high octane fuel..
ok checked and re-set all spark plug gaps and went for a nice little drivie with the 98 fuel and sure enough the problem is fixed thanks for your help fellas
