missfire on LEXURF III

[scott-lee]

there was an interesting topic covered in one of the uzfe forums on facebook,recently.
several trucks were running with low MPG returns,and after a lot of work,the trouble was traced to electrical issues.all of the trucks,in question,had modified manifolds or looms,or o2 sensor replacements.odd thing was,it reminded me of my physic's o'level exam,as it was to do with ''ohm's law''
if the o2 sensor wires are lengthened, or cut,or replacement ,cheap o2 sensors used,it increased the resistance of the wires,leading to the ECU believing that the engine was running lean,and hence ,increased the ratio. sadly,expensive toyota o2 sensors,costing a small fortune,and stock loom configurations,were the only answer,but put the MPG back to the 25mpg region.
i have replaced all electrical components on my engine,just for peace of mind,and had to get the dizzy caps from the USA, the rest was either ebay, or Japan.the loom has the original o2 sensor wires,untouched,and i have the stock o2 sensors,which have been refurbed,thoroughly .hope this see's me right.

[AlexKzn130]

Alex did you sort out your MPG concerns mate ?

No mate completed my test the other week got 11mpg, 130ish miles on a full tank

[AlexKzn130]

there was an interesting topic covered in one of the uzfe forums on facebook,recently.
several trucks were running with low MPG returns,and after a lot of work,the trouble was traced to electrical issues.all of the trucks,in question,had modified manifolds or looms,or o2 sensor replacements.odd thing was,it reminded me of my physic's o'level exam,as it was to do with ''ohm's law''
if the o2 sensor wires are lengthened, or cut,or replacement ,cheap o2 sensors used,it increased the resistance of the wires,leading to the ECU believing that the engine was running lean,and hence ,increased the ratio. sadly,expensive toyota o2 sensors,costing a small fortune,and stock loom configurations,were the only answer,but put the MPG back to the 25mpg region.
i have replaced all electrical components on my engine,just for peace of mind,and had to get the dizzy caps from the USA, the rest was either ebay, or Japan.the loom has the original o2 sensor wires,untouched,and i have the stock o2 sensors,which have been refurbed,thoroughly .hope this see's me right.

Thats interesting fella i know the orignal owner that got vince to do the swap replaced both o2 sensors during ownership, i assume it was a remove and replace but unknown if he used pony sensors

[scott-lee]

i haven't checked to see if the wiring was altered on my loom,as of yet,apart from the 'stealth' injector wiring,but it's something i will be checking!

[Karma Supra]

there was an interesting topic covered in one of the uzfe forums on facebook,recently.
several trucks were running with low MPG returns,and after a lot of work,the trouble was traced to electrical issues.all of the trucks,in question,had modified manifolds or looms,or o2 sensor replacements.odd thing was,it reminded me of my physic's o'level exam,as it was to do with ''ohm's law''
if the o2 sensor wires are lengthened, or cut,or replacement ,cheap o2 sensors used,it increased the resistance of the wires,leading to the ECU believing that the engine was running lean,and hence ,increased the ratio. sadly,expensive toyota o2 sensors,costing a small fortune,and stock loom configurations,were the only answer,but put the MPG back to the 25mpg region.
i have replaced all electrical components on my engine,just for peace of mind,and had to get the dizzy caps from the USA, the rest was either ebay, or Japan.the loom has the original o2 sensor wires,untouched,and i have the stock o2 sensors,which have been refurbed,thoroughly .hope this see's me right.

Yup,

I deliberately left mine alone, and re used all 4 factory 02 sensors.

I've seen 30 MPG (Not often though as I'm not good at driving economically)

It's also worth mentioning that sensors and actuators/motors are meant to have separate earths too, to reduce interference. I didn't do this on mine, it works well, but it annoys me that I "could have done better"

I might rewire it.

lol.

[3 LIONS]

Sorry to hear that Alex, I would have thought if it was electrical wouldn't the engine run uneven or rich in some way if it was to do with the O2 sensors cable ? if it's using so much fuel that it's not burning it then you should get a strong petrol smell from the exhausts and most likely a grey/blue smoke when you open it up , if it's white then it's poss head gasket, but like I said you haven't mentioned that it is running rough as a bag of spanners so if that's not the case I still think myself if there is something well wrong with the gearing mate. Does it go up through all the gears OK , I think it's 7 on that auto box, also sounds like a daft question but the 4x4 low isn't stuck in is it, mine won't engage even when the light tells me it's in.
You most likely have already tried , but have a look on the lextreme site see if there's a post on there with similar symptoms.

[AlexKzn130]

Yup,

I deliberately left mine alone, and re used all 4 factory 02 sensors.

I've seen 30 MPG (Not often though as I'm not good at driving economically)

It's also worth mentioning that sensors and actuators/motors are meant to have separate earths too, to reduce interference. I didn't do this on mine, it works well, but it annoys me that I "could have done better"

I might rewire it.

lol.

Don't suppose anyone has the factory ohms resistance for the stock sensors do they?
Would that not be the easiest way to find out?

[AlexKzn130]

Found it 5.1-6.3 ohms at 20 degrees

[3 LIONS]

any luck Alex ?

[AlexKzn130]

any luck Alex ?

Haven't got round to it bud been doing a few 13hr shifts at work so I've been a zombie on my days off lol

I'll let u know soon, need to do a coolant change so Prob will do it then

[3 LIONS]

OK guys been a long time coming but I have decided to part waves with LEXURF III, one of the originals that was converted with the older non VVti THICK CONROD 1UZFE engines , so a supercharger can go on with no internal alteration, the truck has been playing up lately and I am getting too old to climb about the engine bay and fix stuff, it won't rev over 2500 rpm due to either the MAF or ECU , I had the ECU resistors fixed by a good electronics guy but no change, it is still tangerine orange colour but has started to fade a lot to original silver , rusty in normal places, good front wings, passenger electric window won't work, exhausts blow but they are bold , at this moment in time it still has MOT, plusses are, tailgate window still works , has 4 used but good 33 X15X10 tyres and the spare has been kept inside truck and never used, each tyre cost 160 quid a piece new, Nardi steering wheel ? recent headlights replaced with plastic back ones so never rust. She has to go so I don't want folks asking to buy the wheels alone ok my mob number is 07979436934 call me if you are interested, these engines alone sell for good money due to the thick conrods, and the wheels and tyres are worth buying. or you can message me on here. Been a good old motor but I'm just getting too old for him, they call it the ORANGE BEAST round here I'm just south of Bristol UK. Cheers