Hey guys, I've been looking around these forums for the past two days trying to figure out a few things, and I just wanted to make sure I've understood what I'm going to be doing. At the moment im driving around a Holden VN Wagon (with what i believe is a VP motor and gearbox inside). Chassis has 205,000kms. and engine has 170,000km/s. I'm getting pretty crap KM's out of a tank of petrol. I'm a pretty relaxed driver, never really going over 2k RPM unless desperately overtaking or merging from a sliplane. Around 250km/s from full until just above the red section. I originally tried resetting the ECU (remove battery, hold brake for 30 seconds, then leave disconnected overnight) and that didn't help. I've read that a bad O2 Sensor can cause crap fuel consumption and I don't think its ever been changed (yet alone changed within the 50,000k's lifespan!). Would I see an improvement if i changed this sensor? Also what else could possibly screw with my consumption / efficiency? My heater is also really dodgy. Fan settings 1 + 2 don't work, but 3 + 4 are fine. I'm told i need a ~ $100 resistor of some sort that goes under the windshield to fix this problem? It also only gets warm. Ive tried manually adjusting the little white piece of plastic under the dash, no difference. I'm told that I have to replace the heater tap. Is this hard to do? Is there anything else that could stop my heater from working properly? Also I've been reading about the ALDL diagnostic cables. Would one of these cables tell me if my O2 sensor is fried? What else can it be used for? Thanks alot guys! Really appreciate it if you guys could help me out! Adem
Replacing o2 sensor is a good start, and more so the temp sensor may need replacing, cause if its playing up it will consistantly run a rich fuel mix as it thinks the car is cold still. Change your spark plugs if you havent ever done them. I still havnt done anything with the laptop hooked up, but given that the sensors are old, it is better to probably just change them anyway. Look in the how-to's, there is a good write up in there about fixing your fan, and the heater tap is a peice of cake. If you havnt invested in a gregories workshop manual yet, i suggest you get one, it'll be your bible to fixing your car. And do your fuel and air filters, and give it and oil change and filter too. Also if you want to get it running a bit nicer then this is where greenfoam sells his memcals. http://cgi.ebay.com.au/Maximum-perf...ryZ32094QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
I would definitely start with the o2 sensor. Its just an unplug, plug new one in procedure. It should be located on the passenger side exhaust manifold/header. A tune from greenfoam could always help as well, its only $45 or so and can improve your fuel economy pretty well. The resistor is not that expensive and is quite easy to replace. I reccomend getting one from a self serve wreckers so it is a.) cheaper and b.) you see how to take one out and replace it before you do it on your own car. Try and get on from a VR/VS, they fit but are a different shape. They're a more reliable item than you find in the VN/VP. If the o2 sensor is stuffed, there should be a fault code. There is a how to in this section on how to check for fault codes (without the ALDL diagnostic cables) and what the fault codes mean.
Sory to thread jack, but can he do a tune for a dual fuel setup ? or just the petrol side of things ?
Got the links for ya too for the fault codes: Checking For Errors: http://forums.justcommodores.com.au...3937-checking-your-computer-faults-vn-vp.html Fault Codes: Just Commodores - For All Your Holden Commodore Needs
Actually, what you are saying with the temperature meter sounds about right also. For as long as i remember, the temp meter doesn't work, just sits on freezing cold 24 / 7 and every blue moon will jump up to normal, then back down. Do any of you know roughly how much an O2 Sensor, Temp Sensor and Heater Tap will cost? Preferably new...
I just tried what yo said VN2NV, and well it didn't work.. The plug in that guide does nothing, and the smaller plug that looks like an ALDL connector has only 3 wires, Grey Brown and Purple! Either way i dont get flashing lights on the dash
Heater Tap will be around $30-$35 I believe. O2 Sensor depends on brand, Bosch or AC Delco and whether its a 1 wire or 2 wire sensor. But looking at around the $60 mark depending on which O2 sensor you purchase exactly.
where can you buy the sensors from? Holden dealer quoted me $120 for one. Its a 2 wire that i need. Also the error codes refuse to work.. ANy ideas
I purchased my 2 wire O2 sensor from Repco. The 2 wire ones are a little bit more expensive I think, but you still shouldn't pay more than $80 at Repco. As for the error codes, no idea mate. Everyone I know that has tried to do it, its worked. Maybe you will just have to buy the cables.
i pad $65 at holden a couple years ago for a sensor. Another thing to check, that little black box on the fire wall behind the intake pipe. Check to see if the hose is connected and also to see if there is a after market chip/resistor fitted. Some people fit a resistor to it that fools the ecm into thinking the air coming in is cold so it feeds more juice in to get more go. This is assuming that it always uses more juice ever since you have been driving it. PS my std vp only got about 300km of pure town driving but 600 ish on the highway.
