Fuel economy 3.9 with O2 sensors

Quote:

---

The Australian 4WD Action magazine has a good article on improving 3.5/3.9 Rover V8 fuel consumption. All done by Bruce Davis in Sydney.
I noted he has a couple of recommendations on this site, already.

---

I am afraid I have a high degree of scepticism about the published claims.
AFAIK few of the things in the article improve economy. Power yes.

Aligning manifolds and head work would be unlikely to improve economy as at part throttle the throttle blade is the governor of air into the engine.
Things like head mods etc only matter at WOT.
The chip could make it leaner at part throttle, but o2 sensors are a much better way.
The cam may be the major thing to give better economy, but note that Bruce gives an out that it does not improve power. I reckon the engines would not rev at all.
BUT how much do you spend to get 10%???
I suppose if your cam was worn out it would be good to try but what a PITA if it doesn't.
Regards Philip A

I've installed the sensors. So that is two of us now :)

Exhaust shop fitted the sensors for $80 and I did the rest. Still need to tidy up the wiring between the sensors and the loom. Not happy with it at present.

No definitive proof that it is working but after a test drive it certainly is smoother at idle and low revs.

Fuel usage figures will be slow coming as I run LPG mostly and petrol on 4wd trips and when towing in hilly areas etc.

I'll get myself a cheap analogue volt meter soon and that should give me an indication of if it is working properly. Will get my inlaws to pick me up a code reader when they are in the USA mid year.

Here is a link I've been reading tonight.
Fuel injection
Probably been posted before but I like it.

Utemad, that is a good article and luckily confirms everything I discovered by trial and error, and also gives a good theoretical overview.

To get a code reader you should have your relatives contact "Car Cannibal" who are the best known Range Rover wreckers.
I did not find them very professional, as they "forgot" my order for about a month even though they had a USD cheque.Typical wreckers I guess.

The code readers were standard on US spec Range Rover, I think as part of OBD1 requirements. I think I paid USD 50 for a working used one.

I think it also may show that many people who dismiss 14CUX are a bit misguided. They are really good IF WORKING PROPERLY. IMHO many of the problems are caused by unskilled "technicians".

For aorugh and ready test whether the o2 sensors are working have a look at your plugs after a light throttle run. I recently changed mine and they were pure white all over the electrode.
Regards Philip A

Good stuff Justin. Did you happen to take any happy snaps along the way? I am a little behind the 8 ball as I don't know where the ECU is located or what looms I need to be tapping into.

I do have Philip's excellent writeup but not the wiring work for a Disco.

Thanks Philip. I read your post http://www.aulro.com/afvb/technical-...-bad-news.html and have emailed Car Cannibal.

I'll pull a spark plug after a while and see what the difference is in colour to what I'm used to.

One thing that I was concerned about was weather running on LPG would make the 14CUX system richen its mixture to the maximum like I have read can happen on the D2. If it does happen I'll put a switch in (or run it on the LPG changeover switch) to switch between the Aussie tune and the USA tune via the resistor.

Hi Peter.

The Disco1 is identical to the RRC in the way it wires up but things are located in different spots. The earth wire that goes to pin 4 in the ECU is actually already there though. No idea where it goes though so I tapped into the wire and earthed it to a bolt next to the ECU along with the heater earth and sensor shielding wire.

The ECU is behind the driver side kick trim. As is the fuel pump relay (blue base).

The tune resistor is taped to the underside of the thick wiring loom from the ECU directly above the brake pedal. Will have two red wires going to it and is only loosely taped into position. You can't miss it.

I ran the wires through the firewall and down to the pipes.

Sorry didn't take any pictures. If you follow Philip's guide and take into account the Disco1 locations of things then you will be fine.

One thing though is in Philip's guide he said he had to cut a small piece of plastic out of the fuel pump relay base in order to insert the heater spade connector. In the Disco1 I just disassembled the blue connector block, inserted the spade and then reassembled the block. So perhaps the block is different.

Quote:

---

Originally Posted by Utemad

If it does happen I'll put a switch in (or run it on the LPG changeover switch) to switch between the Aussie tune and the USA tune via the resistor.

---

I have been informed than when you change from one tune resistor to another you also have to unplug the ECU for 10 seconds to allow it to re-set it's self.

I've just been through this excercise with my revised engine set-up and new WBO2 Tech Edge instalation.

Would you simply make the ECU main power wire switchable then?

I'm no expert on this stuff but am learning from recent experiances.

S.

I was under the impression that the ECU reset itself every time you switched off the ignition (after the relay clicks)? Although the link above mentions unplugging the computer to reset it too.

The resistor I used was a 3.3k ohm which I put in series with the existing 470 ohm as per the link above.

EDIT: Sorry the above values are incorrect. That is not for Aussie spec vehicles. Aussie spec is 180 ohms so I actually fitted a 3.6k ohm and a 100 ohm resistor to make up the difference (I used two as Jaycar don't carry a 3.7k).

Quote:

---

Originally Posted by streaky

I have been informed than when you change from one tune resistor to another you also have to unplug the ECU for 10 seconds to allow it to re-set it's self.

I've just been through this excercise with my revised engine set-up and new WBO2 Tech Edge instalation.

Would you simply make the ECU main power wire switchable then?

I'm no expert on this stuff but am learning from recent experiances.

S.

---

What sort of WB01 setup are you running? I have a 2E0 that i use for tuning and 2zj and LA1 gauge fitted in the Rangie, this tell me AFR's and provides the wide band and narrow band 02 signals to the Wolf ecu im running

cheers
Luke

I just fitted a switch to go between 180 ohm and 3.9k ohm tune resistance. It is taped to the loom beside the tune resistor so it can't be bumped.

Peter while doing this I took a few photos of locations. I'll add them to this thread later today.