LPG Forum


All times are UTC



Post new topic Reply to topic  [ 56 posts ]  Go to page Previous  1, 2, 3  Next
Author Message
PostPosted: Sun Aug 28, 2016 7:40 am 
New member

Joined: Fri Aug 22, 2014 6:12 pm
Posts: 61
Cheers Simon

all points noted (most of the mapping is done by seat of the pants , thats when the software stays connected - poxy usb connection) , I had already ordered some 5mm ID pipe so got lucky with that , my reducer is an ultragas (highest capacity according to the installer should be good for the job , but probably not up to the job would be my guess) anyway thats why I have some petrol selected once past 3500 plus to help against VSR , I do intend to keep some petrol addition I'm not too worried about using some at that rev range. What in your experience should I be aiming for re settings in the activation and addition times ?

I guess I could drill injectors out to 3mm and start all over again with a lower reducer pressure to bring inj timings into a lower area , there aint much sidewall left on those nozzles though at 2.5mm so could get tricky there as well , think I will keep it as is for time being and keep tweaking until its as best as I can achieve if still not happy - get the drill going again

thanks again

ETA set petrol addition to 20ms for duration of 6ms , seems okay with a bit of tweaking to the map now , will upload some screen shots later


Top
 Profile  
Reply with quote  
PostPosted: Sun Aug 28, 2016 7:18 pm 
New member

Joined: Fri Aug 22, 2014 6:12 pm
Posts: 61
Changed petrol addition to 10ms for duration of 6ms - new map below

Image


I think this is the best I'll get it tbh , quite happy so far but may drill out to 3mm next week when I renew the shorter pipe


Top
 Profile  
Reply with quote  
PostPosted: Mon Aug 29, 2016 2:04 pm 
Installer

Joined: Wed Sep 29, 2010 5:01 pm
Posts: 2921
Location: Yorkshire
Don't read too much into 'seat of the pants', only used to dial out minor drive-ability issues and find best top end compromise mixture - more power can be seen with mixture a bit leaner at top end than on petrol (seat of pants measurement under very few conditions on an RRSC) but we still want mixture to be rich, just maybe not quite as rich as petrol goes. Certainly can't calibrate the full map by seat of pants, for that you need to be monitoring fuel trims on an RRSC.

Really can't see your map being right with that big jump between 2.5 and 3ms, also wouldn't expect numbers to rise according to rpm so much except maybe at around 4ms. If you're not getting engine warning light issues already with map like that I expect you will some time soon - The OBD connection may have delayed the onset of such but unless the map is correct without the OBD connection the engine may run quite often with incorrect mixture, just not seeing incorrect mixture for long enough at any one time, yet, for the petrol ECU to detect a problem.

Say again would disable petrol addition for now, this will give a clearer picture of pressure / nozzle suitability and on what's going on with the map. If you set addition to be active after 10ms and have 6ms addition, in theory engine will be running on 60% petrol if map is correct at that point. Petrol addition can cause drive-ability problems of it's own anyway.

Slightly tricky to drill MJ nozzles to 3mm but I've drilled them bigger.. I drill them in stages, since you've already drilled to 2.5 it shouldn't be too difficult to drill to 3mm as long as you got the 2.5 holes central. Anyway, not a bad idea leaving nozzles at 2.5 for now, already said your map probably isn't right, I don't know your method of calibrating, only way on RRSCs really is to set via fuel trims... Could yet find it's rich at the top end (so numbers would need decreasing) but if mixture is correct or it's lean at the top end with those settings you may find you run out of ginj windows above about 5000rpm for running totally on gas under those conditions - If this condition is detected by the AEB ECU it will switch back to petrol while ever the condition exists (and flash the running on LPG LED on the switch to inform the driver), switching back to LPG automatically again when the condition is over (rpm and/or engine load decreased).

With Matrix selected in software a map figure of around 120 sees gas injector pulse duration = petrol injector pulse duration (with near 0 pressure and near 0 temp correction) at high loads, so ideally (and if reducer is up to it) would want to see figures of around 120 with correct fuelling along the bottom row.. Critical factors here are 'with correct fueling' and 'if reducer is up to it'.. Expecting fueling to be correct by just entering 120 on the bottom row or 2 would be wishful thinking but entering 120 on bottom row or 2 and then adjusting pressure and/or nozzle size until flat out mixture is correct isn't a bad idea.. then move onto setting up the rest of the map. This method ensures pressure and nozzle size combination make the most of injector pulse resolution (ginj not shorter than pinj) without running out of available ginj pulse window / duty cycle. But with injectors that aren't very fast acting this method can mean the injectors would need to work below the pulse duration where they can work / accurately dose fuel at low loads such as idle - this won't be a problem with the MJ's unless reducer pressure stability is poor (higher pressure at low loads than at high loads). You don't have to read much between these lines to realise that for some engines (notably those that make a lot of power for size of engine and idle with pinj at particularly short pulse duration), if injectors are not very fast acting they may be incapable or achieving smooth idle with ability to flow enough fuel for top end power while providing accurate fueling all the way through the rpm/load range. Other than for those conditions the most important criteria for injectors should be combination of reliability and accurate fueling all the way through the rpm/load range. Some injectors are cheap while being very reliable and easily capable of accurate fueling for most installs, even not bad at working down to low ginj durations. Other injectors are more expensive with hyped reliability but won't work at as low a ginj and while being no different in terms of accurate fueling. Still, having read that, some people seem to reckon they will end up with a better system if they read up on injectors themselves and second guess my recommendations on parts - which I will have chosen for tech reasons.

Bit of an aside but I've also converted some RRSC's with MJ's without nozzles fitted at 0.9 bar (MJ's flow that well!) but particularly without nozzles it's necessary to ensure all injectors fitted flow the same (manufacturing tolerances / injector batches), nozzles help iron out any differences in flow rates of the injectors themselves.
Many types of reducers can reach higher flow rates when set at higher pressures, so a reducer that can flow enough gas for say 380bhp at 1.6 bar might not be capable of flow enough gas for 380bhp at 0.9 bar. This doesn't say much about pressure stability though, a reducer set at 1.3 bar might hold 1.3 bar pretty well but set to 1.6 bar pressure might fall to 1.3 bar at higher loads anyway, or maybe pressure will be more stable at 1.6 bar... I know these characteristics for a wide range of reducers but not Mygas.

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


Top
 Profile  
Reply with quote  
PostPosted: Mon Aug 29, 2016 5:00 pm 
New member

Joined: Fri Aug 22, 2014 6:12 pm
Posts: 61
Hi Simon

loads for me to take onboard there

I have been using an elm obd code reader and watching fuel trims and using the laptop and driving all at the same time - it takes some doing and is akin to plate spinning and juggling 5 balls all at the same time , as you will know!

I'll take on board the issue regarding petrol addition and disable this now - re selecting matrix in the software is this still something I should do even though the software version i have installed has magic jet in the drop down selection menu for injectors?

The reducer is set to 1.6 bar and does indeed drop to 1.3 bar under heavy load , will this cause much of an issue? I guess the way to get around it is to drill out the nozzles further and reduce the set point of the reducer and start all over again?


Finally I'm 110 miles from you - I've got a feeling I may be heading down your way if I don't manage soon :-)


Top
 Profile  
Reply with quote  
PostPosted: Tue Aug 30, 2016 8:06 pm 
Installer

Joined: Wed Sep 29, 2010 5:01 pm
Posts: 2921
Location: Yorkshire
Looking at screens while driving... yes I know what you mean!

Do select Matrix rather than Magic Jet even though you're using MJ injectors and MJ setting is available. The MJ setting incorrectly assumes MJ injectors won't work properly below something like 3ms, if you've been otherwise using decent calibration procedure this could be the reason why your map figures below 3ms drop away sharply - you'd have been attempting to lean off over-rich mixture but the ECU would nevertheless pulse injectors for the minimum duration it thinks MJ injectors are good for. I'm sure I mentioned setting injectors to MJ in software earlier... ;-)

Reducer dropping to 1.3 bar under heavy load might/should be OK with MJ injectors. If you use the calibration in reverse order setup method I mentioned earlier, then you still want to see ginj fairly equal to pinj at full load, regardless of what pressure the reducer falls to under load.

RRSC's are easy to get running on gas without drive-ability problems, more involved to set them up bang on thus preventing the MIL light from coming on a few days later. Most likely due to this point I may yet see you ;-)

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


Top
 Profile  
Reply with quote  
PostPosted: Tue Aug 30, 2016 9:01 pm 
New member

Joined: Fri Aug 22, 2014 6:12 pm
Posts: 61
hi Simon

I tried the matrix selection and it gave me an awful calibration map and said injectors too small

I noticed there are matrix , matrix hd, matrix xs15 and matrix xs20 , which should I be selecting for calibration?

heres a screenshot of the map with matrix selected , if this is the correct selection I used looks as if I will need to drill out to 3mm?

thanks again

ps could you drop me a pm of how much you'd charge to sort this out if I'm unable to achieve a decent result , I will need new pipes routing from injectors to manifold , and possibly could go a higher capacity reducer if required , but would like to avoid this if possible

thanks in advance

Image


Top
 Profile  
Reply with quote  
PostPosted: Wed Aug 31, 2016 11:26 am 
Installer

Joined: Wed Sep 29, 2010 5:01 pm
Posts: 2921
Location: Yorkshire
After changing injector type in software the pressure setting in software might be reset, in which case you'd need to change it back to 1.6 bar before attempting any mapping.

Yes use Matrix setting. It does look as though 3mm nozzles would be more suitable but since you have 2.5 nozzles fitted and reducer set to 1.6 bar already you might as well see what figures you'd need in the high load area of the map... I expect too high but worth checking.

You have been adjusting map according to fuel trims, not just by comparing pinj or seat of the pants when switching between petrol/gas?

Wouldn't be much use me just advising to drill nozzles to 3mm, set reducer to 1.3bar and sending you a config file because setup will partly depend on aspects of your fuel return (if your petrol pressure reads different to the pressure on the vehicle I calibrated any map I sent you wouldn't be suitable).

What size did you say holes are in manifold nozzles? If no smaller than 3mm your current nozzles may be OK, though it's good to have bigger holes in manifold nozzles than in injector nozzles (no smaller). As said earlier, manifold nozzles on an RRSC can be a pain to fit / for access and it follows also to remove (if threadlock etc was used), the rear most port runner on the passenger bank of cylinders particularly difficult as that runner is partially obscured by the petrol rail.. Would be good if the manifold spuds don't need to be changed!

Wouldn't worry much about pressure falling from idle of 1.6 to full load of 1.3... but unless you've checked calibration where the engine is making full power we don't yet know if the engine is running rich or lean. If the engine is running lean the reducer will need to flow more gas to make the mixture correct.. Also, if reducer pressure is currently set at 1.6 bar and it falls to 1.3 bar under heavy load then if we set pressure to 1.3 bar we might expect it to fall to below 1.3 bar under heavy load. If your map is currently near correct for 1.6 bar and 2.5 nozzles, then if you do go to 3mm nozzles would leave reducer pressure alone at 1.6bar for now. Again the iffs are critical... Need to confirm calibration is correct at the moment for proper insight on what to do next.

OK will send a PM.

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


Top
 Profile  
Reply with quote  
PostPosted: Wed Aug 31, 2016 12:06 pm 
New member

Joined: Fri Aug 22, 2014 6:12 pm
Posts: 61
Thanks for the reply and pm Simon

I will reply by PM also but to keep those interested and informed :-

this morning I have drilled out the injectors to 3mm and selected matrix in the software and calibrated again

I have used up all the battery on my laptop trying to map and don't think I'm too far away now - time will tell - pic to follow.

re nozzles in manifold - I know the manifolds weren't removed for drilling , I think they're either 5mm or 6mm nozzles.

I left reducer set point at 1.6 bar

car drives ok so far on this map , may need some further tweaking though


Image


Top
 Profile  
Reply with quote  
PostPosted: Wed Aug 31, 2016 12:24 pm 
Installer

Joined: Wed Sep 29, 2010 5:01 pm
Posts: 2921
Location: Yorkshire
1.6 Setting in software too?

The OD of manifold nozzles (spuds) may be 5 or 6mm, I was talking about internal hole size of spuds... Unlikely to be below 3mm but some types are, if spud internal diameter is smaller than injector nozzle diameter then manifold spuds will effectively be doing some metering when gas injector duration (duty cycle) is high... i.e. end up with gas at higher pressure in the pipe between spud and injector than manifold pressure / instead of individual pulses of gas the engine gets more like a steadier stream of gas. Worth saying unlikely again.

Would now be checking your petrol return is working properly... Compare petrol pressure readings when running on petrol (various driving conditions) to petrol pressure when running under same conditions on gas - Is your petrol pressure reading much different (higher) when running on LPG?

When battery is recharged, could you post software screen shots of engine running on petrol (idle and fairly high load) and of the same running on gas? Idle easier than high load, for high load will help to drive on same stretch of road at same rpm with same manifold pressure reading (can be seen in LPG software), engine in closed loop mode all the while (should be closed loop at fairly high load anyway on RRSC with it's command mixture and wide band lambda probes).

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


Top
 Profile  
Reply with quote  
PostPosted: Wed Aug 31, 2016 4:37 pm 
New member

Joined: Fri Aug 22, 2014 6:12 pm
Posts: 61
yes still 1.6 is software

idle on petrol is 32.2 - 34.4 psi fuel rail pressure
idle on gas is quite steady 33.5 psi fuel rail pressure - I guess he has made a decent job of the fuel return


pressure under steady load on petrol is 32.6psi
pressure under steady load gas is 33.9 psi

idle on gas Image

idle on petrol Image

petrol under load (if its readable) Image

gas under load (if readable)
Image


ETA Photos when running are not showing true RPM reading for some reason - actually rpm was 2250 , wife assures me screen was not frozen - me I'm not so certain


Top
 Profile  
Reply with quote  
PostPosted: Wed Aug 31, 2016 4:54 pm 
Installer

Joined: Wed Sep 29, 2010 5:01 pm
Posts: 2921
Location: Yorkshire
hitman wrote:
ETA Photos when running are not showing true RPM reading for some reason - actually rpm was 2250 , wife assures me screen was not frozen - me I'm not so certain
I expect your wife was right, funny things happen on certain engines with certain LPG ECUs.. Chances are if you turned off the engine and restarted it it would read correct RPM again... for a while! Other than that to correct this issue you might try experimenting with: Temporarily ticking the box that denotes rpm wire connected (beside 'revolution type signal'), this allows changing the previously greyed out 'revolution signal type' setting from standard to weak, and greyed out setting 'ignition type' from 2 coils to 1 coil or rpm sensor. Then unticking the tick box again (because at the moment you don't have the brown rpm wire connected - do you??)... That shouldn't work (as the only thing changed are greyed out settings) but I and other installers have found it can work. If that doesn't work, try ticking the 'rpm wire connected' box and actually connecting the rpm (brown) wire to an ignition coil.. You could also try using a different version of software, a different laptop, a different cable, uploading different firmware to the LPG ECU but I'd expect none of these to work. At least this is happening on an 8 cylinder install, not on a 6 cylinder install where often when this type of issue is seen other more problematic issues are also seen. The issue won't be making any difference to what you're doing yet (and won't cause any problems yet) but can still lead to drive-ability problems later. When I've seen this rpm issue in the past I've wondered if it was just a case of the data stream from the LPG ECU to laptop not updating the laptop's rpm reading (the LPG ECU itself continuing to react to actual rpm rather than frozen rpm).. but I confirmed this wasn't the case - When the rpm reading stops reading correctly the LPG ECU acts according to the same rpm reading (that would be shown on screen with laptop connected) regardless of whether the laptop is connected or not and also the issue can arise at any time. More on this if it comes to it.

Screen-shots could show your engine is running open loop on bank 2 (bank 2 trims show the same in all screenshots, while bank 1 trims do change). With this condition would expect your engine warning light to be on. Check for trouble codes, note any that are present, clear trouble codes and do screen shots again. If the MIL light never comes on despite you trying (could disconnect an injector pipe thus causing a misfire for this) to bring it on, could mean someone has somehow disabled the MIL light.

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


Last edited by LPGC on Wed Aug 31, 2016 6:09 pm, edited 1 time in total.

Top
 Profile  
Reply with quote  
PostPosted: Wed Aug 31, 2016 5:42 pm 
New member

Joined: Fri Aug 22, 2014 6:12 pm
Posts: 61
Simon - your bang on the money , in the pm I sent I mentioned that a smell of gas was present and I suspected cracks to the injection pipe to manifold nozzles and you suggested that could lead to lean codes - well I do have a pending lean code on bank2 that would explain the open loop running and that IS the bank that I suspect has a cracked pipe on.

I'm awaiting pipe to arrive but suspect it may be a bit of a job changing those out , do you need to use a boroscope to see whats what or is it doable with a light and bit of good luck?

ps CEL is not disabled works as required

pps IF its not the cracked pipework causing bank 2 to have stuck trims what else could cause that?? or could that just be a glitch in the software? the trims were definitely changing on my eml code reader
eta
ppps - going to hook up the laptop again and see if they're changing as required


Top
 Profile  
Reply with quote  
PostPosted: Wed Aug 31, 2016 6:04 pm 
Installer

Joined: Wed Sep 29, 2010 5:01 pm
Posts: 2921
Location: Yorkshire
Can't see a need for a borescope.. Assuming the installer fitted normal spuds in usual place (not straws) just try pulling existing pipes off and fitting new.

Pipes can look cracked from outside but be gas tight inside, unusual for pipes to have deteriorated on an install as new as yours if correct spec LPG pipes were fitted..

Leaks between pipes and spuds / injectors possible, vacuum leaks between spuds and manifold possible - and may be more likely on an RRSC with spuds in usual place as it's difficult to fit them in those positions.

Feed pipes to injectors should be near equal in length and bend for injectors to see equal pressure when under heavy load but wouldn't expect this to be apparent under loads in screen shots.

With 3mm nozzles in injectors, slightly different flow from different injectors could be apparent (previous injector batches point).

Could be some aspect of the engine itself - not to ring alarm bells but say if compression were slightly different on one bank compared to the other, the difference might be more apparent on LPG leading to wider differences in fuel trims on LPG than on petrol.

If no leak is found and a bank to bank trim issue remains, then more likely than any of the above you just won't have got the curve of the LPG map correct.. Particularly at the low duration injection times on an RRSC the curve of the map becomes more important, and besides your fuel trims on both banks point to slightly lean - chances are that increasing numbers in both 2.5ms and 3.0ms rows by around 10 linear or 5% will prevent the lean code when running on gas (this might work even with a leak but in case of a leak fixing the leak is of course the correct fix, else there will be other problems).

Particularly if the lean code is only pending, not a hard code yet, would expect bank 2 to start running closed loop again after engine restart. Still best to reset all codes, so you can at least see if the pending code returns. A lean code can be pending while the engine still runs closed loop.

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


Top
 Profile  
Reply with quote  
PostPosted: Wed Aug 31, 2016 6:33 pm 
New member

Joined: Fri Aug 22, 2014 6:12 pm
Posts: 61
Hi Simon

trims confirmed flip/flopping okay but general positive on bank 2 , suspect air ingress , was okay before I strted messing so suspect cracks in pipes causation , will sort once new pipe arrives , have added a tad to the map

screen shots under load show trims changing now with correct rpm

on gasImage

on petrol Image


Top
 Profile  
Reply with quote  
PostPosted: Wed Aug 31, 2016 8:00 pm 
Installer

Joined: Wed Sep 29, 2010 5:01 pm
Posts: 2921
Location: Yorkshire
Looks like you hardly changed the map - so would expect the difference in trims to be due to one or combination of trims settling down (maybe due to warmer engine) / rpm reading correctly / reducer temp correction settings (unlikely) / you maybe sealing a leak / something going on with MAF sensor. Probably the rpm reading correctly.. again this shouldn't make a difference but does.

Also your trims are now more positive on bank 1, the opposite of before. Are you reading trims from the ELM interface of LPG system when you refer to bank1/2? The LPG system banks may be the opposite of petrol system banks depending on how the LPG system was wired in (not good practice but only downside is less intuitive diagnostics).

Would expect your combination of 3mm nozzles and 1.6 bar to need lower numbers in the map tbh. Have you checked trims at higher load areas of the 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


Top
 Profile  
Reply with quote  
PostPosted: Thu Sep 01, 2016 8:08 am 
New member

Joined: Fri Aug 22, 2014 6:12 pm
Posts: 61
hi Simon

our posts crossed I had made the small adjustment to the map before reading your latest post , I will add another 3 or 4 % to the area you suggested and see how fuel trims are today , I was resding trims on code reader not lpg software , I have also added to the bottom 3 rows as was getting multi misfire under rapid heavy acceleration , seems to be better now , will upload map later

thanks again

ps trims at high load area were calling for up to +40% (stft) have added more to map to help


Top
 Profile  
Reply with quote  
PostPosted: Thu Sep 01, 2016 9:26 am 
Installer

Joined: Wed Sep 29, 2010 5:01 pm
Posts: 2921
Location: Yorkshire
If trims were reading correctly in software in last few pics there'd be no need to increase map numbers for those conditions.

If you've needed to increase map at high load area, should compare pinj to ginj, if ginj is much greater than pinj might need more pressure or bigger nozzles... But first: Check again that petrol pressure is around the same (running on petrol or gas) at high loads, most likely will be but worth the check. Bare in mind that during misfire conditions trim info (at least for affected banks) is meaningless, misfires mean the unburned air and fuel are just pumped straight into the exhaust and will cause invalid lambda readings. Also check trims at high loads on petrol and (since we've already checked petrol pressure is nearly the same on petrol/lpg) compare pinj at high loads between gas/petrol (by switching between the 2 fuels without moving foot on throttle).

As memory serves, RRSC's seem to have multi layer fuel trims... we're used to long term and short term trim but on relevant vehicles there is an underlying trim (kind of a base trim). If the base trim is incorrect, e.g. say lean, then might expect long/short trims under certain conditions to reflect high positive values - the thing is this may not mean the map is actually lean under those certain conditions, it could instead mean the map is rich under other conditions. The real fault under these conditions might be that the curve of the map is wrong (how numbers in map change between each row from low load area to high load area)... Thus the checking that everything still seems normal on petrol (trims etc) after you've run on gas and cleared trouble codes. Does your ELM show any other trim information besides long and short and if so how do those figures change when switching between fuels under different conditions? You did disable sequential fuel changeover earlier like I said (will allow a more immediate comparison when you switch fuels while holding throttle steady)?

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


Top
 Profile  
Reply with quote  
PostPosted: Thu Sep 01, 2016 3:16 pm 
New member

Joined: Fri Aug 22, 2014 6:12 pm
Posts: 61
double post :roll:


Last edited by hitman on Thu Sep 01, 2016 3:22 pm, edited 1 time in total.

Top
 Profile  
Reply with quote  
PostPosted: Thu Sep 01, 2016 3:21 pm 
New member

Joined: Fri Aug 22, 2014 6:12 pm
Posts: 61
HI Simon - elm only shows stft and ltft for each bank , figures don't change that much when switching between gas/petrol

NO more troubles codes running the map shown below , the lean pending on bank 2 has cleared and not came back so far - haven't had opportunity to do comparisons under heavy load yet (no assistant available lol) , but when really hoofing it I still have misfires - thing is on 3 cylinders and they are all on the opposite bank of the engine to where the reducer is situated , so my logic says the reducer maybe isn't up to the task under heavy rapid load as thats the area I'd imagine to have the worst supply of gas.

This doesn't concern me too much - the biggest ultragas reducer I ahve seen online is supposedly rated at 300bhp - I think my engine is approx 400bhp so that could be an issue - I know that some are pessimistic in their claims and some are optimistic - who knows in my case the true capacity of the reducer.

when I say it doesn't concern me too much my plan is still to slipstream some petrol in once in the 12ms range I think I'll try with an addition of 3ms and see how that goes. I know you pro's don't like to use petrol but if it helps my situation (hopefully) and also combats against VSR I'm more than happy to burn a little bit :-)

re change over still have sequential change over selected , only other options available are mj sequential or full group , so thought sequential was the one to keep??

map below

Image


Top
 Profile  
Reply with quote  
PostPosted: Thu Sep 01, 2016 4:39 pm 
Installer

Joined: Wed Sep 29, 2010 5:01 pm
Posts: 2921
Location: Yorkshire
Does ELM show anything like post cat trim or total trim?

Unlikely that the misfires occur on the bank furthest from the reducer simply due to being further away / longer piping etc. If furthest injectors were fed in series through a rail on the nearest bank this might be the case, otherwise I doubt it. Obviously make sure there are no kinks etc in the longer feed pipe. Would need to see what happens regards fuelling / trims to comment much further but there is a 'bank trim' control that does what it says on the tin - can increase/decrease fuelling for what the LPG ECU sees as bank2 by a percentage (plus/minus% compared to the map), or if the adjustment is necessary on the bank which the LPG ECU sees as bank 1 it's possible to effect the same (without changing wiring) by adjusting the map until bank 1 fuelling is as required and adjust the trim until bank2 receives the same fuelling as before. The need for a bank trim could point to a shortfall in some other aspect of the system, e.g. if injectors on bank2 flow 10% less than bank1 then a 10% positive bank2 trim would even fuelling between banks out, but there would be a problem if this meant bank2 injector duty cycle exceeded injection window. The real fix here would be addressing why injectors on bank2 flowed less than injectors on bank1, not often due to pipe lengths etc in the real world, more often due to oxygen probes on last legs or injectors with different flow rates.

A 400bhp supercharged engine actually produces more than 400bhp, it takes a fair bit of power to turn the supercharger. Not much of a point because a none supercharged engine producing 400bhp would in most cases need to be bigger or higher revving, so would maybe use a similar amount of fuel to produce 400bhp anyway!

Can try the petrol addition and, as you say, might even have to given limitations of your reducer regardless of nozzle size. Combination of pressure and nozzle size are what dictates the figures in the map, the numbers in your map are higher than ideal and could mean LPG injector duty cycle exceeds available injection window at combinations of high rpm and high load, you already cranked reducer pressure to 1.6 bar which is probably near the reducer's maximum pressure (?), so the only aspect you could change the lower figures in the map is nozzle size, which you're thinking would be a pain to change (and may also involve changing manifold spuds). Given the numbers in your map would expect around 3ms addition necessary at combinations of high rpm and high load to avoid LPG injectors exceeding window. Usual signs of reducer limitations being met are when gas pressure falls away usually quite progressively. Usual sign of flow between tank and reducer (tank outlet / feed pipe) being met is when pressure falls away very quickly / greater pressure fluctuation near the onset of the condition.

Confusing 'change-over' screen with sequential changeover. Sequential changeover is when the system switches an individual cylinder from petrol to LPG, briefly pausing and then moving onto switching the next cylinder to LPG until all cylinders are running on LPG, this usually gives a smoother transition between running on petrol and LPG. This setting isn't in the 'changeover' screen, it is in the 'gas/petrol' screen and is just a tick box on your system so is either on or off. Unticking the box will see all cylinders switch fuel at the same time, usually better for calibration purposes when you want to, say, compare results between running on petrol/gas and see valid results as soon as possible without moving the throttle. Results seen during sequential changeover are not valid because during that changeover period some cylinders will be running on LPG while some are running on petrol, immediate results just after even none sequential changeover are also not valid until the petrol ECU has had time to compensate the mixture, but none sequential changeover shortens the none valid period.

You didn't mention what trims show when running on petrol at high loads? Now the LPG system is set up well enough to be able to provide fuelling that is in the ball park at higher loads, did you mention how petrol pressure reading when running on LPG at high loads compares to petrol pressure when running on petrol at high loads?

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


Top
 Profile  
Reply with quote  
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 56 posts ]  Go to page Previous  1, 2, 3  Next

All times are UTC


Who is online

Users browsing this forum: Google Adsense [Bot] and 3 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB® Forum Software © phpBB Group