Morning
I've been lurking here for a while but got my account opened recently
I'm an ex mechanic who now works in a motor factor (mainly because i prefer to stay kinda clean)

I have a BMW X5 3.0 2002 with the following conversion that was fitted about 5 years ago
73l spare wheel tank
omvl injectors
zavoli vaporiser
lpg tech ecu
flash lube
(apologies for the lack of info i'm going off the original fitting receipt)

when i bought the car i was told that the engine management light was on and "they all do that on LPG"
not a statement i believe i hasten to add

My fault code reader came up with running lean and lambda sensors

the running lean was down to a ripped intake boot (common on the BMW's) and a blocked crankcase breather system
the lambdas checked out ok but were still triggering the EML so i changed them all to eliminate them

i got rid of the warning light and random idle issues but i've now found another problem

when on the motorway and you "boot" the car to overtake it triggers the EML and cylinders 5/6 misfire
i've checked plugs and fitted new ones (ngk lpg1's i think they were) and also replaced all the coil packs

I've then checked the fuel trims and they are miles out on 5/6 (6 is the worse)
if I reset the adaptions and run the car gently (no heavy acceleration) then it runs brilliantly on LPG

if i run it on petrol and boot it then the problem doesn't happen and the fuel trims stay even across the board

I'm pretty sure that the problem is something to do with the LPG system and i'm pretty convinced that it's going to be something stupid like the vaporiser is too small for the engine size/bhp output

I know i could leave it alone and just drive it gently for the duration but i'd like it to be right

i have changed the LPG filter and I've put 6 new LPG injectors (the same as it had originally) just in case it was them causing the issue (it wasn't)

thanks in advance

Did you use the nozzles from the old OMVL injectors in the new ones? (Should have).

I expect you'll just have a calibration issue. The 6 cyl BMW's of that era are a lot more demanding to calibrate properly than the V8 models, especially the engines that have the 'idle air' system.

There could also be a problem with where the installer fitted outlet nozzles in the manifold on the affected cylinders - do all 6 seem to be fitted in a similar position on the manifold port runners?

Also, have a look at where the air pressure reference for the petrol pressure regulator leads to... BMW 6pots of around that age may have atmosphere referenced petrol pressure but the LPG installer will almost certainly have referenced LPG pressure to manifold vacuum, which makes calibration more tricky... but don't disconnect the LPG system's vacuum reference from the manifold or that'll just make things worse.

You could get hold of a cable and software and try setting it up yourself, and I'm pretty sure that if someone else had replied first that is what they would have suggested, but as an LPG installer who knows how tricky the 6pot Beemers can be to set up properly I think you'd be better off visiting an installer who knows what he's doing with these engines...

Very likely the LPGTech ECU was left to self calibrate in 'Tech mode'. After a brief check over of the system and test drive to see what was going on with readings etc, it's likely that the first thing I would do with your system is switch the LPGtech ECU to manual calibration mode and set it up properly from scratch.

Simon

_________________
Full time LPG installer
Servicing / Diagnostics / Repairs to all systems / DIY conversion kits supplied with thorough tech support
Mid Yorkshire
2 miles A1, 8 miles M62,
http://www.Lpgc.co.uk
Twitter https://twitter.com/AutogasSimon
07816237240

Hi Simon
Yes i took the brass insert out of the new injectors to make them 3mm (i think) the same as the old ones

the outlet nozzles are all in the same respective places right down on the edge of the inlet manifold

the air pressure info comes from a nozzle that is drilled into the manifold (over No 4 cyl) i'm assuming thats the vacuum pipe that runs through a little control box at the back of the engine and then up to the vaporiser ?? its fitted in in a similar way to the flashlube which is over no2 cyl

I do have the LPGTech software and i did run an auto calibration before i realised that it was the state of the engine causing the problems not the LPG install
as soon as i figured out my mistake i re-loaded the original installers map

the original installer has not set up the system using "TECH mode"

but i've just realised another problem i have
the original installer has set it all up in polish and when i plug in the option to change language only gives me the option to stick with polish

if i could get it into english i might have a chance of re-mapping but in polish i'm completely stuffed even with google translate

Does it still do the language without connecting to the ecu? if not then you might need to run the installer again, at the start is a selection for language I would guess if it has defaulted to Polish at that point that it may not install the English options.

And no your correct the eml light shouldn't be on on lpg, typical of either an issue with the system itself, or the way its been installed and setup.

The lpg plugs are generally a waste of money though unlikely to be your problem. You mention the vapouriser, any idea what vapouriser it is thats fitted? (a photo may well help with that, you can link to a photo on photobucket etc using the post at top of forum)

yes the software gives me the option to choose language if its not connected to the ecu

lpg plugs ..... I'll be honest our NGK rep gave me 2 sets for free so thats why they went in (yes he did make sure that they were the right equivalent)

the EML doesn't come on anymore except when the car misfires after putting my foot down .... turn the engine off and then back on and it goes (but stores the fault in the cars ecu)

it's got a zavoli vaporiser .... i did google it once and tbh its probably a little over capacity but i'll find out the details later when i'm at home

I'm convinced that it's something with the LPG system purely because the ignition system is all fine and it pulls like a train on petrol with no problems

Does sound like it, as Simon's suggested in his post they aren't the easiest to calibrate anyway, so chances of error much higher.

At that price you can hardly refuse for the plugs, so fair play on that. Its not like they are some of the other makes of lpg plugs at least, which you definitely do not want as they are known to cause issues.

You can adjust the pressure on most vapourisers so it may not be a capacity issue. But given your seeing the same cylinders every time have you had a look at the hose arrangements for them? Slight kink on the hose can cause issues.

Is the rpm wire connected, and if so to where? Also be aware ignition that seems perfectly fine on petrol can cause problems on lpg, though given new coils and plugs its unlikely to be an ignition fault

if memory serves me the rpm wire is off No1 coil

The hoses for the injectors were looking a bit worse for wear so i got a length of hose from tinley and new clips and replaced them all .... no kinks and no fix either

The vaporiser is a zavoli zeta-s and according to Tinley that's good enough for 250 bhp.... The X5 should be around 230bhp

I have a daft question..... Can I wipe the LPGTech ecu and restart it in English?

I'm sure you could, no idea how though. Simon might be able to advise.

I find it really quite strange that it would lock in any language though personally. It should only be the software that knows much about the language anyway. I take it changing the language in the lpgtech software before connecting isn't helping?

Lol no I've tried that and as soon as you connect to the ecu it switches back to Polish
The original installer was I believe Polish (he used his name to set up the map etc) and if so I suspect that it was to ensure returning business (not happening)

BTW the install is over 4 years old so not a recent one or covered by any warranty

LPGTech (the manufacturer) puts different firmware onto ECU's for different countries - If you have an ECU that wasn't destined for the UK, the software won't allow you to use English. The part of the firmware that affects this isn't updated when you upload new firmware (so perhaps it is the boot loader or something). So, if you select English in the software but the software reverts back to Polish, you have an ECU that wasn't supposed to be destined for the UK, one that wasn't sold in the UK by the official importer, grey import, and you are stuck with Polish.

Chances are that the calibration is wrong... usually I would say rich (since misfires) and that might be the case here. Autocal doesn't do much really, just guestimates shape of the multiplier line based on injectors set in software and shifts that full line up or down based on correct level for idle conditions. But, the Beemer most likely has atmosphere referenced petrol pressure, leading to low petrol injector pulse duration at idle (due to higher than normal petrol pressure), so multiplier at idle needs to be high, and multiplier high at idle will mean autocal will set multiplier high at heavy loads too. A pseudo fix for this would be to manually adjust the multiplier to be leaner at heavy loads, pseudo because this doesn't address the fact that a given petrol injector pulse duration can inject different amounts of fuel at different manifold pressures due to the fixed petrol pressure but the LPG system won't be set to account for that difference because it assumes petrol pressure is referenced to manifold pressure (like LPG pressure is). I set the LPG ECU to correct for this aspect when I convert relevant engines but it won't be possible with LPGTech... nevertheless LPGTech is no more disadvantaged in this respect than most LPG ECU's and very good results should be possible (as they are with other LPG ECUs).

Most LPGtech fitters use Tech mode, which like I implied above doesn't do a great job of calibration - but perhaps in this case it might have done a better job that the installer! I have sorted a lot of LPGTech systems, both modes, but I reckon most of the vehicles I put right with LPGTech using 'standard mode', with software locked to Polish, will have been fitted by the same installer.

Although... another common problem with BMWs is brought about by people fitting incorrect MAF sensors, they can look very similar between BMWs but have a different spec, I doubt this will be the problem in your case but worth mentioning. Also, cam sensor issues are fairly common on them.. sometimes not affecting petrol running much but affecting LPG running more. Any latent codes for cam sensors? LPGTech can connect to a cam sensor to pickup rpm, which could also mess up cam signal if done wrong.

Simon

_________________
Full time LPG installer
Servicing / Diagnostics / Repairs to all systems / DIY conversion kits supplied with thorough tech support
Mid Yorkshire
2 miles A1, 8 miles M62,
http://www.Lpgc.co.uk
Twitter https://twitter.com/AutogasSimon
07816237240

You might be able to get round some of the language issues using a second copy of the software alongside to translate what your seeing on the screen then. IE run it on another machine, or in a VM



More likely given what Simons said that its come over from Poland in the back of a Van or similar. Doubt its anything done to particularly lock you out of going elsewhere, theres a lot of Polish Gas Convertors about (or has been), hardly surprising as its more common over there than here to find LPG fueled cars, Plus some of the kit (lpgtech and KME, plus most of the tanks) are made there too.

Hi Simon
I had an issue with a recurring fault that could have been either mass air flow or cam/crank sensors so I ended up changing all the sensors on the engine (work in a motor factors so it's cheap(ish))
I had a quick look again at the reducer and it could actually be a zeta-n or s.... Some kind person has drawn an S in permanent marker on the zavoli sticker but there is definitely the word normal above the zeta-??

What does the gas pressue show when running looking at the software?
Cis. Gazu on the righthand side if its the same one I'm looking at.

The n shows 1.2 bar output, the s 1.4 (I would assume that means its fixed at a set point not adjustable, Simon can probably advise better on that)

I've not been able to plug the car in tonight but I had a quick look at an oscilloscope trace that I recorded last time I had it plugged in
Gas pressure was at 1.4 pretty constantly unless I revved the car when it increased to 1.53
Firstly that tells me that I do have a zeta-s vaporiser
But whether it's supposed to increase like that I honestly don't know

Forgot to add..... I knew about having 2 windows open 1 in Polish 1 in English
When I open the oscilloscope trace it shows me in English

Sounds normal - there will be a reference to manifold vacuum on the connection on the side, more vacuum will cause it to flow more gas, so some raise in pressure. Its not doing anything unexpected there. And as you say that suggests Zeta-s which is what you wanted.

You might be able to load your saved settings into the software without being connected to the ecu and get it to be in English, I don't have a settings file to try that with, but think it would be worth a shot so as you have a better idea of what your looking at?

Yep I can do that ... and in english too
cant see anything out of the ordinary on there but i also cant do a screenshot on the work pc so i cant upload a pic for you all to look at ... i think thats one for tonight on the laptop at home

Would expect a Zavoli branded reducer to be a Zeta N or Zeta S. It is possible to adjust pressure of both but only by a bit, small range of adjust-ability is probably the worst point against otherwise very good reducers.

You can check to see if lack of flow capability is causing a problem by simply monitoring pressure on screen when you drive the car flat out, but since (as I read Ians posts) the problem happens even at low rpm when accelerator is pressed hard, this doesn't seem to be the direct problem.

Just to clarify - When you took nozzles out of injectors, did you replace them with nozzles from old injectors or don't you have any nozzles fitted? OMVL SL's seem to come in about 3 different internal gas routing sizes and, of course, running different internal spec injectors without nozzles results in different gas dosing. If I fit SLs without nozzles I make sure I fit a matched set, otherwise would end up with different per cylinder fuelling / bank trim problems.

Would expect 1.4 bar with SLs from one of the higher flowing batches fitted without nozzles to be a bit a little bit too much pressure for the X5's 3L. At medium loads and when the engine is running OK without misfires etc, reading OBD live data what are fuel trims like? And how does gas injector duration compare to petrol injector duration?

I think I mentioned/implied earlier above that the 3L Beemers of certain eras can take a bit of skill to set up/map properly... Autocal usually doesn't deliver a workable map on these engines because the shape of the map needs to be very different to software anticipated shape of map.

Simon

_________________
Full time LPG installer
Servicing / Diagnostics / Repairs to all systems / DIY conversion kits supplied with thorough tech support
Mid Yorkshire
2 miles A1, 8 miles M62,
http://www.Lpgc.co.uk
Twitter https://twitter.com/AutogasSimon
07816237240

Hi Simon
i replaced the old injectors with same make / type
the new ones came with a small brass reducer thingys screwed in but as the old ones didnt have them i removed them
i have tried running the car with the old injectors in and had exactly the same issue

when running normally the fuel trims are pretty normal but after it misfires 5/6 are way out and the car idles lumpy
clear the adaptions and then take it easy and it runs like a dream
i'll have to check the fuel/gas injection times this evening