Hi,
I have an EFI 2.6L auto TR Magna. About 2 months ago the fuel consumption dropped 15% suddenly. I thought it was bad ignition timing, went to manipulate by advancing it but got pinging and poor acceleration so I undid that. I am thinking bad oxygen sensor, but there is no check motor light so, my question is can an oxygen sensor still function but give poorer readings and the ECU not inform there is an engine fault? I do feel the exhaust smells rich where before there was no smell (my mom complains a petrol smell is coming inside the car) and even though its winter the rich smell is still there when the engine is fully warmed up. The odometer reads 224,000+ and I got the car when it had 186,000. I have no idea when the oxygen sensor was last replaced but believe they last about 100,000kms.

Regards,
Rauli

I'd definetely be looking at your O2 sensor. If you're getting a rich smell and poor economy, change it out. From memory the O2 sensor doesn't throw a code on any Magna.

Coolant temp sender

Coolant temp sender

yeah especially in winter i think this could cause such problems.

Cause in reality fuel economy should be better if anything

Hmm. Thanks for the input. I will replace the O2 sensor and if the other sensor is not too expensive that aswell. I have not noticed any unusual temperature variations though the car does take longer to warm up but I thought that was just because of winter.

I worked out what causes the creaking noise I posted about months ago, the rear control arm bush on the drivers side slips. Guess I will have to replace it or perhaps bodgy it up by putting a rubber sheet to compress between the bush and the U bracket more so it stops slipping. Thats cheap generic bushes for ya.

Regards,
Rauli

Hey Rauli,

Just fyi.. there is two sensors on the cooling system. One is directly for the temperature guage readout (on the dash). And the other sends information to the ECU. If the sensor is faulty and the ECU is constantly thinking its running cold, it will enable the cold start enrichment mode.

Just some food for thought. Personally, i'd do the coolant sensor before the O2 sensor.

Good luck mate.

If none of the above fixes the issue, check the fuel tank vent lines. The first gens seem to be prone to having issues with the pipes perishing and allowing the fuel to just vaporise out of the tank, and it may be similar with the second gens. Just a thought though.

Hey all, just wondering, I filled up last saturday and reset my counter to test how many k's i get to a full tank. anyone got any Ideas? I'm running the 2.6 Astron 4 Cyl. I think there may be a small leak in the air filter box, as when the accelerator is depressed hard, it makes a deep growling but quite disturbing noise from that region.

Thanks heaps.

-Ian

P.S- Gregory's suggests that it may be O2 sensor. It also says things like air cleaner element, coolant temp sensor and exhaust blockages. I'd check O2 sensor first though.

Hey all, just wondering, I filled up last saturday and reset my counter to test how many k's i get to a full tank. anyone got any Ideas? I'm running the 2.6 Astron 4 Cyl. I think there may be a small leak in the air filter box, as when the accelerator is depressed hard, it makes a deep growling but quite disturbing noise from that region.

Thanks heaps.

-Ian

P.S- Gregory's suggests that it may be O2 sensor. It also says things like air cleaner element, coolant temp sensor and exhaust blockages. I'd check O2 sensor first though.

i recon u'll get about 400-500klms out of a tank. just a guess mind u.
As for the noise do u have a k'n filter? maybe the leak in the box is making you hear the k'n sucking in air maybe?? have you got an exhaust leak?? like at the bottom of the headers\flex peice. How old is your water pump belt?? maybe it's starting to crack and groan? maybe the bearings in the water pump have gone. to check that get a long metal rod of some sort, with the engine running put one end on the case of the water pump and the other end to your ear. The noise u hear should be smooth but if it's rattley and loud then the bearing might have gone.

It could be a few things, so unless we can see and hear it we need more info to go on. So during the day pop the hood and get a mate to give it a few revs and see if you can spot where the nosie is coming from.then get back to us and see if more members have better idea's of what it is:)

and exhaust blockages.So would a gunked-up cat cause worse economy? Pretty sure mine's dead, or at least dying, but at the prices I've been quoted ($220+) I figured I'd put it off. Need valve stem seals first.

Anyhoo... RE: k's/tank, if it's running OK you should expect between about 8-10 k's per litre, depending on driving (city/freeway, lightfoot/leadfoot...), see how many k's you're on when you next fill, see how many litres it took to fill this time, and extrapolate. eg. 400k's off 45litres gives 8.9k's/l, which for my records is a bit low but acceptable. If you can get closer to 10 you're doing probably about as good as can be expected, if you're getting less than 8 I'd start to seriously investigate something being wrong.

Think the best I've had in the past few years is maybe 11 or 12, pure highway/freeway driving, about 550 off 45 or 50 litres.

That's a manual V6, but I think they are supposed to be roughly about the same economy.

So would a gunked-up cat cause worse economy? Pretty sure mine's dead, or at least dying, but at the prices I've been quoted ($220+) I figured I'd put it off.

Yeah that's what I'm thinking. The book says exactly this:

"7) Exhaust system blockage: Check the exhaust system for damage and remove any restrictions."


As for the noise do u have a k'n filter? maybe the leak in the box is making you hear the k'n sucking in air maybe?? have you got an exhaust leak??

Nah, don't have a k&n. wish I did though. I've popped the bonnet before and accelerated using the cable on the throttle body. It's definately coming from the air filter box and the pipe leading into it. I know that having a dodgy intake can increase consuption (had an experience with my sister's subaru), but I want to know if that bark means that there's a leak.

thanx.

It's definately coming from the air filter box and the pipe leading into it.$10 can get you another airbox from the wreckers.

$10 can get you another airbox from the wreckers.

hmm okay, ill drop by there on the weekend maybe. one question, who thinks I should get a new air box and panel filter or just go with pod and adaptor?

fanx,
-ian

P.S- raulitech, let us know how it goes when you fiddle around. it'd be great for future ref if anyone needs help with this same issue.

ive been reading this as well cause im having the same issue. found out about the coolant sensor/coolant temp sender from this thread, cause otherwise all the other parts are new and still getting about 430k's from 55 litres

ive been reading this as well cause im having the same issue. found out about the coolant sensor/coolant temp sender from this thread, cause otherwise all the other parts are new and still getting about 430k's from 55 litres

its always good to have a look through other people's threads, maybe they're having problems you are. OR, you'll read through em, and then one day it'll happen to you and you'll know what it is. you know?

I have tested the coolant temperature sensor located on the drivers side at the bottom of the radiator and it appears fine.

I let the engine reach normal temperature, turned the engine off, attached to alligator clamps from the 3 volts light based continuity tester. The light turned on and after a couple minutes went off. I started up the motor again, in about a minute the light came back on, shut the motor off and again in a few minutes the light on the continuity tester went off. From that basic test I ascertain that the coolant sensor is ok. According to my gregory manual the sensor has an open circuit at some temperature and at about 85 celcius has a closed circuit.

I will try unplugging the oxygen sensor, if the engine fault light does not come on then whoever mentioned the oxygen sensor failure does not return a error state to the ECU is correct and I guess the oxygen sensor is at fault.

I have more problems, my rocker cover gasket started leaking oil and I replaced it. Again immediately it started to leak I removed it and used gasket goo but now it started to leak again. I tightened the bolts on the rocker cover, I heard a pop sound and now the bloody thing has a hairline crack :( this is the second time this has happened. I can't find my torque wrench, it went missing along with some other things when I got a wheel alignment on my car recently...dodgy mechanic I think. So I could not tighten the bolts to specifications.

What kind of rocker cover gasket sealing agents do people recommend? When the front of the car is slightly dipped I sometimes get a white smoke coming from the engine bay, motor oil getting on the exhaust pipe :(

Regards,
Rauli

mate, i cracked my rocker cover aswell. just get a new one form the wreckers, it won't cost you that much. as for the sealer goo, i used a bright blue one. i don't remember what it was called, but the tube and contents are blue. mine hasn't leaked a single bit.

and for heavens sake get yourself a new torque wrench, coz if you overtighten it, it might leak also.

good luck,
-ian

P.S- you're not supposed to use the same rocker cover seal twice. the dude at auto barn told me so. then again, I did, and didn't have any probs.

Thanks for the info I will follow it. I had a torque wrench but when I got a wheel alignment last time, it disappeared.

Regards,
Rauli

Hey all,

I'm definately using TOO MUCH fuel. I've been driving around today, started with 65 km's on counter, now up to 188. I drove aroundevdeavour hills/berwick/harkaway and I only have 1/2 tank left. Referring to my earlier post, I filled up on saturday 30th June. That's the day I did 65kms (It's been sitting in the yard til today)

Anyone also think this is abnormal consumption?

fanx,
-ian

You can't definitively say how bad it is based on your fuel guage, unless you have done repeated tests that show that x amount of fuel is typically used at "half" guage.
As said previously, you'll need to fill up and see how many litres that 188k's has used. Post up how many litres were used, and then we can start to make an informed judgement.

One person's guage can be drastically different from another, the only way to judge it is to get to know your car through repeated and repeatable testing. For example, I know that from the quarter-full mark on mine is a 45litre fill almost on the dot every time. And I can get between 70 and 130km's from a fill before the guage even hits the top of "full"!

Im in the same boat mate. my economy just dropped a fair bit. at 3/4 of a tank i had done 140km as opposed to the usual 190km. could just be a one off.
ive got a new oxygen sensor for all of you who dont have abetter answer lol.

normal driving too, so not sure what else it could be

Hey all,

I'm definately using TOO MUCH fuel. I've been driving around today, started with 65 km's on counter, now up to 188. I drove aroundevdeavour hills/berwick/harkaway and I only have 1/2 tank left. Referring to my earlier post, I filled up on saturday 30th June. That's the day I did 65kms (It's been sitting in the yard til today)

Anyone also think this is abnormal consumption?

fanx,
-ian

Considering my car has majorly worn chains, which are extremely slack and causing the cams to fall outa sync, and i get around 350km to a tank... i think there is seriously something wrong with urs... As I did mention in an earlier post though, check the vent lines on the fuel tank. A simple split line will be allowing the fuel to just vaporise from the tank itself, and will bring economy down significantly, not to mention is a serious risk from fuel vapours floating around near the cat converter...

Why dont you just see how much fuel you use from F to E?
get the recipet print out from the servo and write on it how many k's you got to that tank...