Fuel efficiently

[Shiggins]

So I have the new 02 sensors in ( this solved the surging problem),new air filter, new fuel
Filter, new 777 injectors and cleaned the throttle body and sensors.

It looks like the fuel efficiency is going a bit better but I still want to do everything that I can to help it. I can't remember if i replaced the spark plugs and leeds when I first got the jeep 2 years ago so I'm considering changing them do I need to gap them or should that already be done if I get the correct plugs? The other thing is the dizzy cap and rotor. The one I have looks to be in good Condition. It's clean and I can't see any burn or shock marks on it. Is it necessary to replace if it looks in good condition?

[bruggz351]

We've discovered a funny thing regarding fuel economy with our XJ.

Woolworths premium, the top notch 98 octane stuff. The ol' girl runs beautiful, smooth and responsive. Good economy.

Any, ANY, other fuel from any other company and the performance goes down the drain and economy worsens.

I find this quite bazaar.

And we won't even bother mentioning the corn fed shite.

Sent from my HTC_PN071 using Aussie Jeep Offroad mobile app

[Capt. Crunch]

Originally Posted by bruggz351

We've discovered a funny thing regarding fuel economy with our XJ.

Woolworths premium, the top notch 98 octane stuff. The ol' girl runs beautiful, smooth and responsive. Good economy.

Any, ANY, other fuel from any other company and the performance goes down the drain and economy worsens.

I find this quite bazaar.

And we won't even bother mentioning the corn fed shite.

Sent from my HTC_PN071 using Aussie Jeep Offroad mobile app

Interesting...
I usually use Caltex 95 octane but I've noticed now that between 95, 91 and 98 there is only a 0.1-0.2km/l difference. Mine's worsened recently and I'm sitting at 15.8/100 or 6.3km/l. Can't figure out what's changed though as I've done all the above mentioned services a year or so back.

On the 91 though I can feel it's lost power so I'll stick to 95.

Had a check engine light come on randomly while driving yesterday though so I need to find out why.

[junglejuice]

Originally Posted by bruggz351

We've discovered a funny thing regarding fuel economy with our XJ.

Woolworths premium, the top notch 98 octane stuff. The ol' girl runs beautiful, smooth and responsive. Good economy.

Any, ANY, other fuel from any other company and the performance goes down the drain and economy worsens.

I find this quite bazaar.

And we won't even bother mentioning the corn fed shite.

Sent from my HTC_PN071 using Aussie Jeep Offroad mobile app

When mine was OBD1 and stock manifold etc I found mine was cheaper to run on premium then it was on regular (and other members on here told me I was wrong!!), the increased cost per litre was offset by the reduced consumption (and noticably better performance), only problem was the lack of premium in remote areas, once I didthe 99 manifold mod and a TBS my consumption dropped on regular and premium made bugger all difference, I've not tried it on my OBD2 set up...

[Capt. Crunch]

Originally Posted by junglejuice

When mine was OBD1 and stock manifold etc I found mine was cheaper to run on premium then it was on regular (and other members on here told me I was wrong!!), the increased cost per litre was offset by the reduced consumption (and noticably better performance), only problem was the lack of premium in remote areas, once I didthe 99 manifold mod and a TBS my consumption dropped on regular and premium made bugger all difference, I've not tried it on my OBD2 set up...

so in your opinion the 99 up manifolds make a worthwhile difference? what kind of improvement was noted?


I've just checked my engine codes and it has given me a 21 so oxy sensor is faulty, can being caked by mud affect it? Find it strange that it's faulty as it's got less than 40k on it.

[anthonygubbin]

Originally Posted by bruggz351

We've discovered a funny thing regarding fuel economy with our XJ.

Woolworths premium, the top notch 98 octane stuff. The ol' girl runs beautiful, smooth and responsive. Good economy.

Any, ANY, other fuel from any other company and the performance goes down the drain and economy worsens.

I find this quite bazaar.

And we won't even bother mentioning the corn fed shite.

Sent from my HTC_PN071 using Aussie Jeep Offroad mobile app

We struggle to get Caltex 98 over here but even Caltex 95 gets me better economy than any other brand that includes BP 98. Funny thing is an friend swears her 07 Lancer gets better economy using at least 95 and it too has to be Caltex. This I know is odd considering all the fuel is supposed to come out of the same tank at the refinery.

Regards A

[junglejuice]

Originally Posted by Capt. Crunch

so in your opinion the 99 up manifolds make a worthwhile difference? what kind of improvement was noted?


I've just checked my engine codes and it has given me a 21 so oxy sensor is faulty, can being caked by mud affect it? Find it strange that it's faulty as it's got less than 40k on it.

As I specified this was on an OBD1 engine and yes it made a difference but so did the TBS.
Mine would ping, badly even when empty on the slightest incline when the temp was moderately warm, add the trailer and it was terrible which made climbing hills difficult when trying to minimise the pinging.
Add the TBS and the pinging disappeared for a while but eventually it came back but slightly less pronounced.
The I added the 99 manifold and TBS and then the pinging disappeared altogether, even when doing the OTT up Cape York in the heat up there towing 1t with the Xj heavily loaded it still didn't ping, not once.
I had a few members here tell me that the TBS catergorically does not work so as an experiment I removed it just before my missus went out in it (it's her daily driver), when she got home she proceeded to tell me that there was something wrong with the brakes as they must be on as the car was sluggish.
I then refited it and upon return she informed me that the brakes were all good again!!
I have to state that my OBD1 engine was down on compression, see this image for a comparison between my original OBD1 and the replacement OBD2 engines...


Also of note that the best ever milage I acheived to date (measured) was with the OBD1 engine, 99 intake, TBS, snorkel, 3.73:1 diff gears, stock 225/75's empty on the highway I got 10.1l/100 for a 100km trip.

Once I fitted the OBD2 engine (still OBD1 PCM, 99 intake TBS etc) my performance increased but my fuel consumption increased once over 100kmh (quite noticable) but since changing to the OBD2 PCM on a recent trip of approx 650km I noticed despite sitting on 110kmh where allowed I actually used less fuel (according to gauge position) then previously for the same trip at 100kmh (stock 97 manifold, no TBS).
I have yet to try the 99 intake with and without the TBS with the OBD2 PCM and I will also be trying a set of 777 injectors as well when I get a chance...