landrover oxegen sensor question

[bigdave18]

Hi All,

I have a landrover v8 that runs on lpg,
my question is it has been fitted with a separate oxegen sensor all of its own but its been fitted to the right hand bank of cylinders on the down pipe and not where both sets of exhausts meet,
im not sure if its running lean because of this, as i cant get it to rev over 3k rpm,
the gas system is a single point leanardo


regards

bigdave

[classicswede]

The sensor position should be fine.

Is the stepper motor going fully open? What make of vapouriser has been fitted? Some avpourisers depending how they are installed can need a build up of heavy ends draining off.

[Gilbertd]

That's exactly what I have on my P38, a separate Zirconia 4 wire lambda sensor in the RH downpipe solely to drive a Leonardo. The main reason why this is done is because the Leo can sometimes have problems with the 5-0V Titania sensors fitted to a GEMS engine. As the LPG system is a single point then you only really need to read the signal from one cylinder, if 1 is right all the others will be (unless you have something seriously wrong with the car).

[bigdave18]

Hi its a omvl r90 if this helps
as for the stepper motor i dont know if it is opening or not is there a way of testing??
also was thinking of giving the vaporisor a service, as i have seen some service kits on e bay

would this be of benefit ??

cheers

[Gilbertd]

Do you have the software and lead to see what the Leo is doing? That will tell you if it is going lean at the top end. My LSE was also going lean if I gave it a big dollop of welly when I first got it. That was on an old Lovato vap but it was half full of 'heavy ends' a sort of semi liquid gloop that can build up over time. Draining that out made quite a difference. If the vapour output on your R90E is coming from the top outlet, get it warm and then take the bung out of the bottom outlet to drain any heavy ends from inside it.

It may also be that your stepper valve is sticking. Undo the two screws that hold the stepper motor to the valve body and give everything a good clean with carb cleaner.

Don't try stripping the vap until you know it needs it. The usual symptoms of needing a rebuild are going rich at idle and seeping gas through the diaphragm to the hole at the back.

[bigdave18]

Do you have the software and lead to see what the Leo is doing? That will tell you if it is going lean at the top end. My LSE was also going lean if I gave it a big dollop of welly when I first got it. That was on an old Lovato vap but it was half full of 'heavy ends' a sort of semi liquid gloop that can build up over time. Draining that out made quite a difference. If the vapour output on your R90E is coming from the top outlet, get it warm and then take the bung out of the bottom outlet to drain any heavy ends from inside it.

It may also be that your stepper valve is sticking. Undo the two screws that hold the stepper motor to the valve body and give everything a good clean with carb cleaner.

Don't try stripping the vap until you know it needs it. The usual symptoms of needing a rebuild are going rich at idle and seeping gas through the diaphragm to the hole at the back.

Hi thanks for the reply, no i have no software or leads for the leo, do you know where i can buy some from??
as for the output it is on the top do what you said and see if it helps.
It does run a little rough on idle.

I want to recheck the timing aswel as i have read that the tdc marks can be wrong on the pulley, i have just spent nearly 1k on rebuilding the engine.
it has now covered 800 miles so its time for a check up !!!
i have done a little bit of digging regarding timing for lpg and there seams to be a range of timing settings from 14deg BTDC to 30deg BTDC do you know what the best setting is??

Im looking to buy one of those advance/retard boxes from rpi as i like the idea having dual timing so its correct in both gas and petrol.
but want to get all the niggles out the way first.

also noticed mine has emulators fitted. and after studying the wiring diagrams of my 97 disco and the leo unit i could just remove them and fit two relays fed from the yelow wire from the leo to cut both banks of injectors.

sorry to go off at a tangent, any help you can give would be great.
thanks

[Gilbertd]

For the lead and software, go to http://www.wtv-uk.co.uk, click Programming Interface Kits on the left and scroll down to AEB-OMVL. That's the one you need but it is serial (RS232) only so you'll need an older computer with a 9 pin serial connector. You can use a USB to serial adapter but they don't always work reliably.

I assume you have the Lucas 14CUX engine with the distributor (so the same basic engine as my LSE) as the timing is fixed on the GEMS engine (which Wikipedia says was fitted to the Disco from '96 but I suspect that was only for the US market). If so, the book says the timing should be as below.





Personally I wouldn't buy the box from RPi. Like everything they sell, it is grossly overpriced and the only time they have been mentioned on here is when they have packed up without warning and caused all sorts of problems. The ignition timing is left as standard on both my cars (well, you can't adjust it on a GEMS) and they run fine. The most important thing is decent quality ignition components, NGK BPR6ES or BPR6EiX plugs, decent HT leads and dizzy cap and rotor arm.

You can in theory remove the emulators but it may flag up the check engine light when the ECU detects an open circuit to the petrol injectors. The yellow wires are normally open when running on gas for this reason, so you wouldn't actually need an additional relay. I would have thought the 14CUX ECU is stupid enough to not notice but my LSE has emulators too so maybe it isn't.

[bigdave18]

Hi,
Thanks for all the info,
I thought because the octane rate was higher than unleaded the timing needed to be changed to get the best out of the gas,
The plugs are the ones u mentioned and are new, along with new cap and rotor arm, plus coil and new ignition module,
It seams ok until it gets to 2.5 k rpm then starts to fade off.
Will have to get the software u recommended
Thanks for your advice.
Will let you know what I find

[Gilbertd]

You can run more ignition advance but the benefits are hardly noticeable. Just because the LPG can run with more advance (due to the higher octane rating) doesn't mean you need to. It's a bit like putting Super unleaded petrol in a car that will run quite happily on normal. The Octane rating may be higher but you won't get any benefit out of it.

[rossko]

Has it ever worked ... are you looking for an install/selection problem or a fault that has developed?

[bigdave18]

When i brought the disco the engine lasted a week before knocking its ass off,
so i did not rev it above 2000 rpm

now i have installed a rebuilt engine im finding these issues.
it starts and runs fine upto 2500 rpm then just goes a bit flat, i get no back fire or anything
thinking about it in petrol it not that great after 3000 rpm ither, could be a faulty disy, maybe it needs a strip down and inspection,

i have read somewhere a few people have had issues with the outer ring slipping on the inner part of the pulley thus making any timing marks incorrect.
i need a bit of spare time to check tdc with a dial test gauge, just to busy at the min.

[classicswede]

I do remember years ago having some odd running problems with one of these engines and that was down to the dizzy.

I would suggest getting the software and taking a look at how it is running and it will a good tuning aid anyway.

[SimonHobson]

Try removing the mixer from the intake and seeing what it does to performance on petrol. Mixers are a tricky thing - too big and you don't get enough suck, too small and they restrict airflow. Mine's got a "tad small" mixer on it so it runs OK but lacks top end.

Having said that, it started having problems from cold where it would develop a misfire from about 3k rpm on full welly - but only from cold, and worse on damp mornings. Then it packed up. Next Sat when I got to look at it, it started and ran fine - but then I spotted (well heard) an arcing across the cracked nose of the coil.
Ignition problems can be worse at higher revs as there's less time for the coil current to build up, and larger throttle openings also create higher cylinder pressures. Between these two, it can make the difference between lighting up the mixture and failing.

Also, you never know if the internals of the dizzy are in good form - and giving the right advance curve. If the advance isn't working, then that will drop power at higher revs - but without any reduction in fuel slurping.

[bigdave18]

hi guys only five months to reply,
i have just ordered the lead and software as recommended,
and also took the lower plug to see if the was any stuff in there but all good.
i have had a little bit of joy tho the coil packed up so i put a new one on and its much better it revs past the 3k mark,
so might not of been the lpg after all.
no harm in getting the stuff tho and checking it out as its not running quite right.
but enough to go playing in the mud.

oh and now the lpg gauge keeps lying so another job to sort