KJ Fuel economy thread

[MierMoto]

Holly crap dude, Was it running like a dog, You would have been running on two cylinders!!!, Check engine lights would have come up for the Injector pressure being irregular. it would struggle to start and be way down on power.???

Seeing that I've only had it for a month, I didn't really have a reference to say whether it was running low on power. No lights came on and I've had the bonnet open before this, but the engine wasn't running at the time, so I didn't pick up this issue. When we opened the bonnet the other day, you could immediately hear the air blowing out the top.

The warranty only cover part, probably only half. Seeing that I have this warranty, the dealership probably wouldn't give a hoot if anything went wrong.

This is so bloody annoying. I really like this car and it's given me issues within the first month. Hopefully once this is sorted it'll be good. I can imagine that it'll run heaps better if the issue is fixed and once I manage to bolt the door handle back on, things should be okay.

The problem is that this isn't the only financial thing that's struck us within a week. We got a quote for $12000 to fix the house's roof and then got a bill from daycare for $600 for my daughter's stay over the April holidays, that's after the rebate!

So, holy crap is right.

[MierMoto]

Latest update: Looks like it's not too serious after all. Apparently nothing seems cracked, but a seal is missing off the one injector and the other injector wasn't tightened properly, but he's still got to take a better look at them. We might have to replace the entire injector, but he'll need to take a further look at that. Lets hope it stays there and doesn't blow out to be more of an issue.

The only problem is that he's tried to order parts from Brighton Jeep and they have these parts on back order and it might take 4 to 5 weeks before they get it! I can't wait that long as I'm loaning a car from work to get around with. Are there any stores I can here in Oz or in the US, which you guys can recommend?

[ick72]

would a new motor cost you that much ? could be worth while looking at instead of pay that much onlt to have another prob down the track

[MierMoto]

would a new motor cost you that much ? could be worth while looking at instead of pay that much onlt to have another prob down the track

That's a good point. Where would I get a new motor though?

[adamdebenham]

Is that normal? Did the air filter make that much of a difference?

[adamdebenham]

How can you get better then 16lt per 100.

My 03 Cherokee uses so much fuel. I'm considering an LPG conversion. But are there ways of getting better fuel economy? It's we worse when towing a box trailer, which surprised me? Love to hear how others are conquering this? I'm new to the forum, so love to hear? Adam

[Auberon]

Given the last question:
Probably timely but respectful reminder as these are not scheduled maintenance but should be done anyway: ALL radically affect fuel trim.
and lots of people I note are new to diesels.

This is, of course, dependent on model as some have combined sensors (like the combined boost/intake air temp sensor); but each of the following require attention every second oil change (at least):
air filters;
MAF;
boost sensor also called MAP (Manifold Absolute Pressure).
fuel filter change every other oil change is important. It's an easy preventative maintenance step that many also try to run too long.

Condition of sensors is critical in regard to fuel trim.

ON ECONOMY numbers (manual calculation);
Our 2.8 KJ (2006 CRD) has been running to Mascot from outside the Windsor area regularly and is getting way better than that for economy - probably in the area of 10 l / 100km. Carries ARB bullbar, Warn winch and disability equipment all the time so its not light. Highway running is much better.

When doing this type of running only use BP from the same local garage.

All get regular attention. Other than that: currently no EGR tube (both ends capped) and Samco hoses fitted. The exhaust note is different - sweeter.

Due for oil change and sensor clean at end of month plus fuel filter change will watch with interest.

Hope that is useful.
Interesting point:
The oil stopped gunking immediately the EGR tube was blocked off so the valve can do as it likes - it is a closed system now - at the cooler anyway.

Will watch the new oil (Mobil 1) this time to see how quickly it "gunks" in the absence of exhaust gas. If oil lubricity degrades quickly with EGR pumping soot into it - the first minute if idle has an open EGR valve (I think) and wears a high tolerance motor how is that weighed against the miniscule gains in DIESEL NOx gains in the tiny amount reburned. VERY different to a petrol engine.

[MierMoto]

Update on the injector issue:

The plates, bolts and washers have been replaced on two of the injectors and it's running much better now. Obviously I've gained loads of power as it's now running on 4 cylinders and not just two and half.

It's still using more fuel than it should at about just under 12l/100km, but I think it's running too cold as was previously suggested. The gauge is sitting at less than quarter. I'm taking it to the Jeep dealership in Ballarat this weekend to have checked out anyway. They can plug it in and take a look at what's wrong so we can get everything sorted before it becomes a problem.

Cheers again for all the help. I'm really glad I popped onto this forum.