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 Post subject: Re: BMW X5
PostPosted: Thu Mar 16, 2017 12:38 pm 
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Reading through this I've a couple of observations to make. There's obviously not many customers at Ian's Motor factors and the fact that it is only cylinders 5 and 6 that misfire may point to something silly affecting just those cylinders. To my simplistic brain I would have thought if it was a problem with the map making the mixture go way out, then it would give random misfires on all cylinders and not just on those 2.

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 Post subject: Re: BMW X5
PostPosted: Thu Mar 16, 2017 12:55 pm 
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Gilbertd wrote:
Reading through this I've a couple of observations to make. There's obviously not many customers at Ian's Motor factors and the fact that it is only cylinders 5 and 6 that misfire may point to something silly affecting just those cylinders. To my simplistic brain I would have thought if it was a problem with the map making the mixture go way out, then it would give random misfires on all cylinders and not just on those 2.


LOL obviously i'm a very skilled multitasker
i'd agree that it sounds like something very simple and stupid causing the problem ..... seeing as i've eliminated all the engine possibilities (vacuum leaks ignition errors etc) and it only happens at one specific time in engine use i've narrowed it down to being something on the lpg system and thats why i'm here


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 Post subject: Re: BMW X5
PostPosted: Thu Mar 16, 2017 3:13 pm 
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I tried exploring some of the aspects that could only affect 5 and 6 (injector spec / manifold nozzle position etc). Another thing could be injector plugs swapped over...

On a 6cyl BMW cyls 123 are one bank, 456 are the other bank... So although misfires are only on 5 and 6 when reading trims we're also looking at cyl4.

As with many other LPG ECU's, it is possible to affect fuelling on individual cylinders with LPGtech - click on the 3 dots next to injector type to see relevant settings. If someone has added some percentage of fuelling to 5/6 that could cause misfires on only those 2 cyls.

Simon

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 Post subject: Re: BMW X5
PostPosted: Thu Mar 16, 2017 5:17 pm 
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the wiring is a good call tbh
in my hunt to solve the problem i replaced all the vacuum pipes and pulled the manifold off to replace the gaskets
it's not impossible that i've swapped the wires

but would the car still run as well as it does normally ???


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 Post subject: Re: BMW X5
PostPosted: Thu Mar 16, 2017 6:44 pm 
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If you swapped wires over at injectors would expect changeover between petrol/LPG and the idle both to be rough, as long as you got all wires to injectors on the correct bank I would't expect noticeable problems under constant high load but you might notice a bit of hesitation when changing throttle position.

Since you're running ONVL's without nozzles I still wouldn't be surprised if those you bought are from a batch that has wider internals than those you didn't change (or even if you swapped both rails the new ones might have different specs to each other). Swapping injector rail positions would dis/prove.

Simon

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 Post subject: Re: BMW X5
PostPosted: Thu Mar 16, 2017 7:40 pm 
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evening Simon
I'm going to check the wiring for the lpg injectors this evening (just in case I've made a mistake)
when i replaced the injectors i went for the exact same ones that were fitted originally but it's not impossible that there are manufacturing differences

once I've checked the wiring I'll plug the laptop in and reset the fuel adaptions then take it for a run on lpg and get it to play up whilst recording the info through the lpg software
then i'll reset the fuel adaptions and run it again on petrol and do the same foot down thing and see if i can see any discrepancy on the oscilloscope
finally i'll run it as normal on lpg and gently to see if there is anything i can see on that trace

wish me luck


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 Post subject: Re: BMW X5
PostPosted: Thu Mar 16, 2017 7:54 pm 
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one further thought ... i have refitted the old lpg injectors in the past to rule out a faulty set .... same issue still there so i put the new ones back in
and i replaced all 6 because i couldn't see the point of just doing half the job


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 Post subject: Re: BMW X5
PostPosted: Thu Mar 16, 2017 10:18 pm 
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Gilbertd wrote:
Reading through this I've a couple of observations to make. There's obviously not many customers at Ian's Motor factors and the fact that it is only cylinders 5 and 6 that misfire may point to something silly affecting just those cylinders. To my simplistic brain I would have thought if it was a problem with the map making the mixture go way out, then it would give random misfires on all cylinders and not just on those 2.


I've not used lpgtech, but the same thought was behind my thinking of where the rpm pickup was from.

Of course none of us know if this ever worked that well to begin with, Ian its also possible that the wiring where its taken from the vehicle loom isn't correct - a check against the wiring diagram would prove this, but you may be able to switch cylinders 5/6 over to petrol (not sure if LPGtech does that, or if your particular ECU allows doing that). If it runs ok at that (or noticablely worse) then it may be wiring.

I'd suspect its a mapping issue given what Simon's already said, if you can post screenshots of the map screen that may help?


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 Post subject: Re: BMW X5
PostPosted: Thu Mar 16, 2017 11:32 pm 
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https://www.dropbox.com/sh/b977mtxjyx91 ... dZ4xa?dl=0

I've checked the wiring for the lpg injectors and thats right I've also checked the wiring where it joins the cars wiring loom and thats all good too

took the car for a blast down the local motorway at silly speeds and on petrol it went fine no problems
when i booted it 65/70 to slightly illegal speeds on lpg it first shuts off then when i re-started the lpg (still driving) it started misfiring
this time it only went on cyl 6

switched it back to petrol and wiped the codes on the car and again it went like the clappers with no hint of a misfire


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 Post subject: Re: BMW X5
PostPosted: Fri Mar 17, 2017 10:31 am 
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I had a look at your settings and map in LPGTech software.
It does use Tech mode rather than Standard mode.
There are errors for over-pressure and for short circuit of gas injector 4 but I wouldn't read much into that.

Difficult to get a clear picture of multiplier etc in Tech mode but 2D map seems to show multiplier is too high after 3ms pinj steadily getting richer until about 8ms and then getting leaner again... but I would guess the leaner again after 8ms is incorrect and actually it will be too rich after 8ms. If sticking with Tech mode for now (I wouldn't!) I would have suggested lowering that mixture compos slider which is currently at 1.1 to 0.9, which will lean the mixture, but I've since had a look at your scope files and doing that won't help (see vehicle related problems below)...

Seems ginj is consistently lower than pinj after around 4ms, which does point to too much pressure (as I implied a few times previously). With OMVLs without nozzles on a 3L BMW you will only want to be using around 1bar pressure. A lot of LPG ECU's would report pressure too low / nozzles too small during autocal on the BMW with 1bar and the OMVLs without nozzles (the LPGTech probably won't come up with any error warning) but any such warning should be ignored in this case, no autocal can anticipate spec of the engine / atmosphere referenced petrol pressure etc. Pity that pressure isn't very adjustable on your reducer and that effectively the next size down for nozzles on your injectors is around 2.5mm... Not a combination of parts I would have fitted on the 3L BMW, because I would have known about the pressure / nozzle size issue. If you can't turn pressure down to below around 1.15 bar you could try fitting 2.5 nozzles and see how it goes but would expect you to need maybe a bit more pressure ideally with 2.5 nozzles - still, even if you can't increase pressure the 2.5 nozzles at current pressure would be preferable to the current setup. Some ECUs are pretty good at compensating ginj during acceleration but unfortunately LPGtech isn't - If Ginj has to be lower than pinj due to combination of nozzles and pressure you might not notice the downsides of ginj lower than pinj during constant throttle conditions but during acceleration, when the ECU can't anticipate what pinj will be so therefore can't anticipate what ginj should be, ginj may come closer to pinj, which in the case of your setup might see the engine getting a 20% overly rich mixture and causing a misfire - more look than judgement that you don't get a misfire on cyls 123 as well with your setup.

The above addresses fundamental problems with your LPG setup but doesn't address problems with the car itself.

Summing up, your LPG setup isn't ideal, would expect inaccurate fuelling and hesitation during acceleration due to ginj being lower than pinj, particularly with the LPGTech ECU. But, your immediate problem is too lean fuelling on cyls 456 especially 56, which may be due to open loop fuelling. Your LPG system is calibrated too rich but 456 are running too lean. But none of this is set in stone / conclusive, because we can't always trust the LPG software to accurately reflect what the LPG ECU itself is actually reading / outputting - those pinj/ginj figures on screen may not be true, the difference between figures for cyls 456 may not be true, but it seems pretty certain that 456 are running leaner than 123.

Also , in the misfire scope screen, we'd better confirm that you either turned the engine off or it stalled and you restarted it at some point around the middle of the trace?

Simon

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 Post subject: Re: BMW X5
PostPosted: Fri Mar 17, 2017 2:32 pm 
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Hi
in the misfire scope @1695s is when i stopped to put petrol in (a rare occurrence)
@2301 is when the gas switched off after accelerating hard (a new issue)

@ 2399 is when cyl 6 cuts out and the misfire starts

I was driving the car a lot harder than normal ordinarily i wouldnt have seen this fault on that stretch of motorway

i suspect that i'm going to be taking the car to a specialist to get this re-mapped .... ideally one a decent distance from me to make sure it is all fixed on the way home


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 Post subject: Re: BMW X5
PostPosted: Fri Mar 17, 2017 2:38 pm 
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I've just realised that i've uploaded the wrong techset :(

i'll update it now


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 Post subject: Re: BMW X5
PostPosted: Sat Mar 18, 2017 10:59 pm 
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Ian's been in touch

Simon

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 Post subject: Re: BMW X5
PostPosted: Sun Mar 19, 2017 9:50 pm 
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LPGC wrote:
Ian's been in touch

Simon


Probably a sensible idea at least most of the other issues hes already sorted.


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 Post subject: Re: BMW X5
PostPosted: Sun Mar 19, 2017 10:09 pm 
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Yup I agree
There may be some stuff that needs doing that I'm definitely not comfortable with getting involved in.... As well as the fact that experience while calibrating is something I definitely don't have


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 Post subject: Re: BMW X5
PostPosted: Sun Mar 19, 2017 10:10 pm 
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Brian_H wrote:
LPGC wrote:
Ian's been in touch

Simon


Probably a sensible idea at least most of the other issues hes already sorted.


I'm probably not quite with it tonight after 11 hours at work on a bloomin Sunday, no food all day (awaiting Indian ;-) ) and a couple of cans, but I don't quite follow what's been sorted already mate? :?

Post crossed with Ians... Luckily I have shed loads of experience calibrating LPG systems ;-)

Simon

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 Post subject: Re: BMW X5
PostPosted: Sun Mar 19, 2017 11:05 pm 
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LPGC wrote:
Brian_H wrote:
LPGC wrote:
Ian's been in touch

Simon


Probably a sensible idea at least most of the other issues hes already sorted.


I'm probably not quite with it tonight after 11 hours at work on a bloomin Sunday, no food all day (awaiting Indian ;-) ) and a couple of cans, but I don't quite follow what's been sorted already mate? :?

Post crossed with Ians... Luckily I have shed loads of experience calibrating LPG systems ;-)

Simon


These bits from the first post - the non-lpg bits really
Ians wrote:
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

Plus Ian should learn more info from yourself in person with the vehicle that he'd pick up from most installers, which I'd suspect he wants to be the case having got involved so far in trying to sort it.


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 Post subject: Re: BMW X5
PostPosted: Mon Mar 20, 2017 7:26 pm 
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Cheers Bri, see what you mean!

For the benefit of others readability, here's the last reply I wrote to ians in a PM.
Lpgc reply to PM wrote:
So far I've just looked at the pics.

Your install looks par for the course for an install done anything up to around 10 years ago (I know it's a recent install), fairly long pipes between injectors and manifold spuds etc, not a great deal of thought gone into component selection.

That rail on top of the inlet manifold carries the auxiliary/idle air that I spoke of on forum thread, hopefully the spuds on cyls 5 and 6 won't have gone into the idle air channel (which runs inside the port runners of the inlet manifold) and will be into the main part of the port runner (as they must be on cylinders 1 to 4 since the engine seems to run properly on those cylinders on LPG). This is what I was talking about with spuds in manifold in correct location on 5 and 6.

If a BMW 6cyl features idle air this implies that petrol pressure isn't referenced to manifold pressure, instead petrol pressure will be referenced to atmosphere... yep another thing I mentioned on thread! LPGTech isn't capable of accounting for this, but neither are most LPG system ECU's... Won't be a problem for me to calibrate it with these components, but means autocal and/or a duff installer stands little chance of setting it up anything reasonably close to correct though.

But if a lambda probe is down on bank2, or for any reason you can't get bank2 to run closed loop and properly on petrol, that will be the biggest problem. You'll have to ensure it runs closed loop and properly on bank2 before you come. I haven't checked your other scope readings yet... do you think bank2 is running closed loop and properly on petrol?

Regards, Simon

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 Post subject: Re: BMW X5
PostPosted: Mon Mar 20, 2017 8:49 pm 
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just for the benefit of those reading i thought i'd ask these rather embarrassing questions here rather than in a pm
first closed and open loop lambdas i'm getting so confused with these .... could someone put it in really simple terms for me ??
second how the hell do i test fro the above (out of my comfort zone here)
third i've read the lambda sensor readings on a different diagnostic platform (not the lpg scope) and these are the readings from it
first on lpg
Oxygen-sensor control, bank 1 Active
Oxygen-sensor control, bank 2 Active
Oxygen-sensor controller, bank 1 1.0
Oxygen-sensor controller, bank 2 0.8
Signal, oxygen sensor, bank 1, 0.79 V
before cat
Signal, oxygen sensor, bank 2, 0.58 V
before cat
Signal, oxygen sensor, bank 1, 0.89 V
after cat
Signal, oxygen sensor, bank 2, 0.89 V
after cat
Adaptation, mixture, additive, -0.01 ms
bank 1
Adaptation, mixture, additive, 0.39 ms
bank 2
Adaptation, mixture, bank 1, -8.0 %
multiplicative
Adaptation, mixture, bank 2, -8.0 %
multiplicative

then on petrol
Oxygen-sensor control, bank 1 Active
Oxygen-sensor control, bank 2 Active
Oxygen-sensor controller, bank 1 1.2
Oxygen-sensor controller, bank 2 0.8
Signal, oxygen sensor, bank 1, 0.08 V
before cat
Signal, oxygen sensor, bank 2, 0.50 V
before cat
Signal, oxygen sensor, bank 1, 0.06 V
after cat
Signal, oxygen sensor, bank 2, 0.04 V
after cat
Adaptation, mixture, additive, -0.06 ms
bank 1
Adaptation, mixture, additive, 0.39 ms
bank 2
Adaptation, mixture, bank 1, -8.0 %
multiplicative
Adaptation, mixture, bank 2, -8.0 %
multiplicative

the way i'm reading it is that bank 2 lambda (before cat) is not performing properly ..... not enough to trigger a fault code but enough to cause a problem whilst running
i've looked back through what i've done with the car and the lambdas were changed just over 12 months ago when i bought the car and it had the original running issues due to split boots / blocked crankcase breathers
i've since fixed those issues but obviously the lpg problem could have taken its toll on the new lambda
so do i replace bank 2 pre cat
do i replace both pre cat lambdas
is there something i'm missing here that will just cause new lambdas to burn out again (other than the badly calibrated lpg system)
i'm quietly confident that any problems that were causing issues to the basic engine running (sensors vacuum pipes etc) are all fixed now and if i need to throw 2 lambdas at it before Simon dons his wizards hat to solve the lpg then i'm more than ok with that and i"ll get them fitted this week

ps what i'm learning is that i can follow a diagnostic fault if it gives me plain and easy to understand instructions (preferably written in crayon and with pictures) this lpg stuff is way way above my comfort zone


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 Post subject: Re: BMW X5
PostPosted: Mon Mar 20, 2017 9:52 pm 
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Open loop - running ignoring lambda, usually down to waiting for warmup or a faulty sensor or trim limits reached
Closed loop - trims being adjusted as intended by lambda (how it should be most of the time)

Simon can provide a lot more info and probably will do, but I'd interpret his message above to mean if the spuds (the nozzles that are tapped into the manifold) are in the wrong position (blocking the idle air path i think is what hes getting at - without rereading the whole thread i would take this to mean your manifold has a set of flaps inside the manifold and you may have the nozzle directly in the point where the path is at its smallest, blocking it?, which would probably prevent correct running on petrol hence the reference to lambdas working properly.).

It may be as simple as plugging the hole and tapping a new one. What i think hes trying to avoid (understandably!) is a wasted trip if your not close. If you have access to a boroscope then having a look from the inside of the manifold may answer where the nozzle is in the tract? Otherwise your probably looking to remove the manifold to have a proper look

As far as burning the lambda sensors out, this is possible, but its more likely they aren't seeing the right mixture - how do they behave on petrol at idle? Throwing new sensors at it may not fix the problem if they aren't the actual problem in the first place.

When you do end up going to Simon you will get a much better idea how it works from him, as well as whats actually wrong with your system as pictures can only tell so much.


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