Outer Limits 4x4 Board

Ok we all been once around the table on this...but here goes...

80 Series 1993 EFI 4.5L Peetrol its chewing thru the juice and same with LPG.

It was reasonable around January this year but now its not good the last tank of petrol used approx 85.19L for 309 k's!!! and on LPG on a country run it did 337Km's for 92 Litres in Jan fully loaded it did 498 K's on LPG....

It starts ok although at idle sometimes its pacing up and down very very slightly as its got an vacuum leak but I checked that... What is the best way to check that the EFI and the motor is doing the right thing.

I know that the 80 series is a brick with four tyres but its 100k's or thereabouts changed in fuel economy...

Any thoughts...please constructive ideas only...and no wont buy an oil burner no I wont sell it

Regards

bushpig59

First thing I would be looking at is filters, air and fuel.
Followd by plugs, to make sure the basics are covered, and you dont leap frog over a problem.
Plugs should indicate issues with injectors, if in doubt, run some nulon inj cleaner thru.

Then I would clean out the throttle body assy and step motor.
Its surprising how much problems a dirty throttle body will cause.

Following that, check for fault codes, base idle timing is correct, has it been serviced by someone who didnt quite know what they were doing?

then armed with specs and pressure guage, check the fuel rail pressure etc.
Temp sensor can also cause poor milage, as too an o2 sensor. But these may be picked up by fault codes, but not all the time.

Let us know what you find.

Trains

Hey thanks Trains...

I will go sequentially thru the list as that's how as a technician (that's me fixes or traces faults)

I will post proper figures soon as possible.

Air Filters and Fuel is easy plugs are the Platinum type but will have a look..

Is there an easy way of reading the fault codes? I have laptops computers etc but not a way of reading them...Id be interested in try to get a low cost solution for that?

Oh forgot to tell you my Brother in law is a mechanic but is on holidays.

Also I'm suspecting the o2 sensor may be a culprit but not sure.

Really big thanks for the reply though

Regards
John

Definately change the air filter.

and work through the list presented one at a time. makes alot of sense to me

Trains is on the money.

Also check the hose between the air flowmeter and the intake doesn`t have a hole in it. Is a common thing for this to split and it will cause hunting in the revs at idol and huge fuel usage.

Thanks Guys for the advice ....my bro inlaw has informed me he has an engine analyser $9000!!!! I get to play with it this weekend it tells you all the codes etc...

Should be interesting will let you know how I go.....apparently you require a pilots license...will take pics and give you stats too

Cheers

Try the O2 sensor.

Steve.

One other thing that can easily be forgoten is tyre pressures.

Any news bushpig? Trying to fix the same problem myself.

Gwagensteve wrote:Try the O2 sensor.

Steve.

how do you check it steve?

yup 02 sensor

If your 80 is pre 2/ 1995 it is most probably the 02 sensor, as this sends back signals to adjust tune and doesnt usually set off a fault cose, just goes out of calibration....other things to consider aswel is brakes dragging??? jack the wheels up and try to turn them/see if they are free....rer handbrake could be an issue, front calliper is also possible to sieze...then there is exhaust....baffles have been known to fall off in the muffler and restrict exit of exhaust...have you been up the cape lately?
Andrew

dow50r wrote:If your 80 is pre 2/ 1995 it is most probably the 02 sensor, as this sends back signals to adjust tune and doesn't usually set off a fault cose, just goes out of calibration....other things to consider as well is brakes dragging??? jack the wheels up and try to turn them/see if they are free....rer handbrake could be an issue, front calliper is also possible to sieze...then there is exhaust....baffles have been known to fall off in the muffler and restrict exit of exhaust...have you been up the cape lately?
Andrew

ok all good ideas!!!!

1993 One O2 sensor? Near the Cat ...is it a spark plug looking thing?

Borrowed off the Bro in law the the engine analyzer used in on Friday nite could not get auto readings had to go manual its only read some things useless to me such as throttle control , engine knock sensor , rich lean mixture.... And the Bro in Law went back on Holidays lucky him so I have to wait to get some idea what really is going on....

When he gets back will try to test again and post all my findings

Started checking over mine for leaky hoses etc, found on the side of the air filter box a valve thing that must take pressure readings on the pre & post side of the filter & one of the small hoses was kinked over, replaced it but still too early to tell if it has made any difference.

Also found on mine this morning, the intake pipe from the air box to the intake manifold has split right through. Basically the air flow meter was reading nothing...

That's more like it.
Hope you haven't dusted your motor.

The air pressure monitor across the element won't have any effect. it only runs an idiot light.

Steve.

Mine was pretty sudden, then this morning must have been when it broke clean in half. Toyota wanted $160 retail, but ended up getting for $127 trade.

phippsy wrote:Mine was pretty sudden, then this morning must have been when it broke clean in half. Toyota wanted $160 retail, but ended up getting for $127 trade.

Ebay cheaper again i know they are for hilux by about 50 bucks

Sic Lux wrote:

phippsy wrote:Mine was pretty sudden, then this morning must have been when it broke clean in half. Toyota wanted $160 retail, but ended up getting for $127 trade.

Ebay cheaper again i know they are for hilux by about 50 bucks

Had a look there, couldn't find any in wreckers, but then I would still have one that was as old or older than the stuffed one I've already got.

phippsy wrote:Also found on mine this morning, the intake pipe from the air box to the intake manifold has split right through. Basically the air flow meter was reading nothing...

Guts wrote:Also check the hose between the air flowmeter and the intake doesn`t have a hole in it. Is a common thing for this to split and it will cause hunting in the revs at idol and huge fuel usage.

So yours wasn`t hunting up and down in the revs? Both my hilux and 80 idol like crap if this isn`t sealed 100% Funny how different engines do different things for the exact same problem

Yeah, the revs were varying a little bit, but didn't put it down to this at first. Checked the plugs, air filter etc, but the it wasn't till the pipe broke completely that it wouldn't idle . I'd had the top off the filter box the day before to blow out the filter and the pipe was still in 1 piece.

Have had some cars where they seal up at idle put them in gear or load the engine then it opens the crack up and makes it hunt.