Weird Engine Light Diagnosis

[joe seinfeld]

V6 VN with a wreckers VP engine.

Ok so a while ago i did the fault check and got O2 sensor.

Haven't got around to replacing it because ive had absolutely no time and its a complete dog to get out.

What ive been noticing is that my check engine light comes on ONLY when i have extra weight in the car. It doesnt stay on the whole time, but comes on more frequent when there is more weight in the car, and im 100% sure of this.

For example, fill up petrol, light come on, stops comin on around just above half a tank.

Driving around by myself, nothing, pick up a mate, he sits in the car, light comes on.

WTF???

any idea? ive been takin care of it too, doin services myself pretty often and dont smash the hell out of it either.

im stumped

[somefool]

lol Id use that as a joke.
-friend gets in the car-
you: you fat bastard your making my car spit warning lights at me.

ahh. ha. ha. ha. ha. ha.

um it may have something to do with the car burning a lil more fuel to move the extra weight, an that different mixture might just be pushing over the limits of the pxy sensor, tripping the warning light.
Reset the ECU and see if it makes a difference? - disconnect a battery lead for 10 minutes or so.

[joe seinfeld]

lol Id use that as a joke.
-friend gets in the car-
you: you fat bastard your making my car spit warning lights at me.

ahh. ha. ha. ha. ha. ha.

um it may have something to do with the car burning a lil more fuel to move the extra weight, an that different mixture might just be pushing over the limits of the pxy sensor, tripping the warning light.
Reset the ECU and see if it makes a difference? - disconnect a battery lead for 10 minutes or so.

ok yeh ill disconnect it tomorrow when i get home and see if i keep gettin the same warning lights.

Dont i have to hold it at 3000RPM aswell or something to reset it?

Also now that you mention the fuel thing, its absolutley shockin on fuel, just over 200k's to a tank and thats with very VERY easy driving, and making sure to sit it in low revs uphills and accelerate downhills etc just to see if i could get better fuel consumption, and thats still what i ended up with , just over 200k

[ybl8te]

spark plugs - leads - fuel regulator - thermostat - broken vac hoses - temp sensor - o2 sensor - m.a.p sensor

somethings too check and all will make you use more fuel,.............m.a.p sensor should (i think) if you pull the vac hose off you should blow black smoke, then its working - simple little checks, do you have a multi meter to check sensor's ohms readings ??

Have fun, my vn v8 was using gas - all due to thermostat slightly stuck open, not allowing the engine to get hot enough, therefore dumping more fuel in to warm up !!

[joe seinfeld]

yer in terms of the fuel consumption im planning to do most of the things that take a bit of time in the holidays, and im doing the thermostat this weekend.

Im pretty sure the thermostat may be the culprit as the car never seems to heat up to a normal temp, but would it really be givin me 200ks to a tank for just the thermostat you think from experience?