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Re: system throws low gas pressure fault and wont manually switch untill high reducer temp

Posted: Sat Feb 09, 2019 10:53 am
by Brian_H
Did it switch over ok at that? You have the injector warming set when temp is below 15c, it was showing 7.5 so should have been warming that being the case. But if it is a solenoid problem might be an intermittent issue, particularly if its gummed up inside.

If it did fail to switch, the snapshot data might give a bit more idea what's going on there.

Re: system throws low gas pressure fault and wont manually switch untill high reducer temp

Posted: Sat Feb 09, 2019 11:14 am
by Darren
the picture of the settings was taken when the car was switched off, the freeze frame happened after the car warmed up. when the car finally did switch to gas i went into the diagnostics tab and manually switched it over from petrol to gas a few times and the solenoid on the reducer only clicked once for each action. now im confused why it clicked a few times when switching to gas the last time i testes it a few days ago.

Edit: will also add a pastebin of the backup that might also be helpful https://pastebin.com/DasUNAEA

Re: system throws low gas pressure fault and wont manually switch untill high reducer temp

Posted: Sat Feb 09, 2019 3:50 pm
by Darren
Ok just did a test and backed up the firmware to the previous version. Checked the "hemi" option in the settings and started the car when it was at about 13c reducer temp. I setup a recording on the kme software and the second it hit 26.3 it switch over to lpg without a problem. now i just need to wait for a complete cold start to see if it is fully working so im not getting too hopeful until then and will post another update after a cold start to let you two know how its going, thank you for your guys' help so far though!

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Re: system throws low gas pressure fault and wont manually switch untill high reducer temp

Posted: Sat Feb 09, 2019 8:12 pm
by Brian_H
I've noticed the Nevo (both the 4 cyl and 8 cyl ones) on my vehicles will sometimes click a few times before switching over, but its not usually a problem. it seems more likely to do it when there is no pressure in the system (I've noticed it more when I've filled the tank from completely empty)

Re: system throws low gas pressure fault and wont manually switch untill high reducer temp

Posted: Sat Feb 09, 2019 10:42 pm
by Darren
went out for a drive just now and the reducer was at 20c with 1.01 pressure when i started the engine, once the engine was running the pressure shot up to 2.01 until the temp got to 26.5 where it switched over to gas and the pressure went back down to 1.32 like normal.

Re: system throws low gas pressure fault and wont manually switch untill high reducer temp

Posted: Sat Feb 09, 2019 11:19 pm
by Brian_H
Just need a few cold mornings for further testing then!

I've known the 8 cylinder kit to throw a wobbly on about 4 occasions recently, though suspect thats either a simple electrical supply issue, or a problem with the alternator/battery as it logs about 5 errors all at the same time and shows an input voltage of 9v in the snapshot. Though switching it off on the drivers switch and back on again gets it going again so not got round to looking at it further as yet as been busy dealing with other stuff (and hard to know if its fixed since it will do it once then be fine for the rest of the day - though with no pattern as its done it on trying to swtich from cold, and also when its been driven for over an hour)

Re: system throws low gas pressure fault and wont manually switch untill high reducer temp

Posted: Sun Feb 10, 2019 12:11 am
by Darren
Yea few more cold starts and hopefully it sticks, what kind of pressure is dangerous? Incase i go out in the morning and its on some oddly high pressure. I wish mine was a simple switch off and on fix but having to pull the car over after a few minutes driving to restart the engine was getting pretty damn annoying!

Re: system throws low gas pressure fault and wont manually switch untill high reducer temp

Posted: Sun Feb 10, 2019 12:29 am
by Brian_H
I wouldn't be too worried about the pressure unless it goes much beyond 2 bar, if anything when its cold the pressure will drop a bit anyway - the main problem is if it gets too high the gas injectors can't open as the pressure against them is too great, this will depend on your injectors as well (if the pressure is too high you might not have sufficient time at idle to inject the required amount of fuel as well, but that depends on a few factors, and can be compensated for using different size nozzles, or by adjusting the pressure setting on the vapouriser to something suitable.

If its throwing low pressure you should find pressing the button once to switch it off, then again to switch it back on (might need to leave a few seconds between presses) to be enough for it to try again - when I've needed the tank empty I've found you can get it to use more off whilst driving like that. It may be that the plus system is different as all of mine are the standard Nevo, or may be a setting you can adjust - Simon would probably be able to point in the right direction there.

Re: system throws low gas pressure fault and wont manually switch untill high reducer temp

Posted: Sun Feb 10, 2019 12:18 pm
by Darren
oh makes sense that it could block the injectors from opening. I have tried that and usually from cold start i have to wait until the reducer was at 70c before it switched over.

Just ran out now for another cold start test and again it threw a low pressure fault, in fact it had almost 0 pressure
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i let it idle on petrol for about 30 seconds then switched the engine off and took another recording and magically there was full pressure.
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so turned it over and straight to lpg it went without any problems, previously if it threw a low pressure fault from a cold engine start it would never switch over either from the control unit or from restarting the engine. it use to only switch over untill the reducer was at a normal temp at 70c.
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so still confused but atleast it builds up pressure once the engine is turned off so i can just idle till switchover temp then restart the car and head out instead of waiting till the reducer is at 70c. only bad thing about cold start tests is that you dont get many chances to test it which is no help at all!

Re: system throws low gas pressure fault and wont manually switch untill high reducer temp

Posted: Sun Feb 10, 2019 12:29 pm
by Gilbertd
It's still looking like it could be a gummed up valve, sometimes it opens and you get full pressure, other times it either doesn't open at all or only opens very slightly so you get low pressure. That would be worse in cold temperatures than when it is warm.

Re: system throws low gas pressure fault and wont manually switch untill high reducer temp

Posted: Sun Feb 10, 2019 12:39 pm
by Darren
was really hoping i didnt have to mess with anything physical in fear of putting it back together incorrectly but ill look at taking apart the solenoid next weekend and see what state its in

Edit: did the imagines show up on my previous post? went to check the thread on my phone and the images didnt load for me

Re: system throws low gas pressure fault and wont manually switch untill high reducer temp

Posted: Sun Feb 10, 2019 3:38 pm
by Brian_H
Darren wrote:
Sun Feb 10, 2019 12:39 pm
was really hoping i didnt have to mess with anything physical in fear of putting it back together incorrectly but ill look at taking apart the solenoid next weekend and see what state its in

Edit: did the imagines show up on my previous post? went to check the thread on my phone and the images didnt load for me
I can see them ok.

Solenoid wise its literally a case of undo the nut on the top of the coil, unplug the coil, slide it off the solenoid, and then slowly undo the post underneath. - Give it a minute or two until the gas stops hissing out of it before undoing it fully (or see if your tank has a shutoff on the valve, if it does shut that off, let the car run on gas to use whats in the pipe up and then remove the post)

Biggest risk when your taking it off is dropping the spring loaded post that sits inside it somewhere you can't find it again. The plunger inside should be fairly obvious how it goes back in (spring towards the top end of the post) and there isn't much else to it really.

If you want to avoid taking it off then try testing the coil for resistance with a multimeter first, but its more likely the plunger mechanism underneath it is gummed up than a problem with the coil.

Re: system throws low gas pressure fault and wont manually switch untill high reducer temp

Posted: Sun Feb 10, 2019 3:58 pm
by Gilbertd
Assuming you have a manual valve, turn that off before unscrewing the post or you'll be venting the entire contents of the tank.....

Re: system throws low gas pressure fault and wont manually switch untill high reducer temp

Posted: Sun Feb 10, 2019 4:37 pm
by Brian_H
Gilbertd wrote:
Sun Feb 10, 2019 3:58 pm
Assuming you have a manual valve, turn that off before unscrewing the post or you'll be venting the entire contents of the tank.....
Yes, definitely with the rear solenoid. I'd start with the front one though first and see if that helps, as thats where the heat from the vapouriser might have an effect.

If its a tank without a shutoff, suggest running it till empty is best first (will depend if its a single hole or 4 hole tank).

Re: system throws low gas pressure fault and wont manually switch untill high reducer temp

Posted: Sun Feb 10, 2019 5:05 pm
by Darren
The tank does have a shutoff screw so ill be sure to remember that. And that sounds pretty straightforward so im a bit less worried now. Just went for a drive now and it threw the error again so connected my phone and just watched the data while i drove around on petrol. Noticed that the pressure was a little all over the place. Would go anywhere between 0.0 and 0.4 mostly being either on 0.0 or 0.3. and looks like im back to square 1 as i was trying to manually change it over periodically but it wouldnt change untill the reducer was at 66c. I also noticed that it changed over at a pressure of 0.24 and only after the buzzer from the control unit confirmed it was on lpg did it shoot up to 1.34 and stayed there. So its looking like it will be something like the solenoid.

Re: system throws low gas pressure fault and wont manually switch untill high reducer temp

Posted: Mon Feb 11, 2019 10:50 am
by LPGC
Pressure will be all over the place before the gas solenoids open because gas vapour pressure will remain constant while manifold pressure rises and falls according to engine load - the pressure reading is gas vapour pressure minus manifold pressure. There's also the additional effect of injector preheating... You start the engine on a cold morning, there may still be some gas pressure, the reading will fluctuate according to manifold pressure (previous point) but will get lower and lower during preheating injectors until eventually if gas pressure equals manifold pressure the pressure reading will be zero.

Still could be a solenoid problem. But try setting delay after valve opening to 2 or 3 seconds, disable cutting of micro injection, I haven't seen pics of your install but it's probably a good idea to set fuel overlap (petrol to gas) to 1 cycle of 2ms.

Can you do a screen shot of the 'advanced' screen?

It can be normal for the pressure reading to reach 2 bar in certain situations... Your reducer is set to normally output gas at 1.3 bar above manifold pressure, at idle manifold pressure will be around 0.3 bar absolute pressure (atmosphere is 1 bar absolute pressure), the gas pressure reading on screen is relative to manifold pressure. If the engine is idling on gas the pressure reading will be 1.3 bar but absolute gas pressure will only be 1.6 bar (0.6 bar above atmosphere), then if you turn the engine off the reducer will for a short time continue to keep gas pressure at 1.3 bar above manifold pressure which is now 1 bar not 0.3 bar so absolute gas pressure raises to 2.3 bar (1.3 bar above atmosphere), then if you start the engine and let it idle on petrol (not switch to gas) manifold pressure will again be 0.3 bar absolute but there will still be gas pressure of 2.3 bar absolute... 2.3-0.3 is 2 bar. If you didn't get the 2 bar reading under that sort of situation it might be because of a leak or because the 'pressure letting off' setting in the 'advanced' screen was set very low. On the other hand, if gas pressure jumps to 2 bar as soon as the solenoids open when the engine is idling with 0.3 bar manifold pressure it might point to gas injector outputs not matching petrol injector inputs per respective engine cylinders (channel routing issue) or long gas pipes between injectors and inlet manifold (which overlap can help address).

The error page is Interesting... E023 is low gas pressure, it does report only 0.2bar, so I wonder why with pinj of 3.77ms ginj is only 2.91ms (would expect with such a low pressure situation ginj to be much higher than 2.91ms)... In the Model screen is idle model calibration ticked?

Would't bother going back to previous firmware. Even if the firmware update did bring on the problem it would only be due to some newly available settings but those newly available settings could easily be set to not invoke the problem.

25c is a low changeover temp for a motor where coolant temp rises quickly (like most BMWs), the engine is likely to be running closed loop but still getting some cold start enrichment at that temp after starting from cold... cold start enrichment is necessary for petrol but is a problem for correct fuelling with LPG.

Whenever there's a low voltage error there will usually be other errors such as switch malfunction and sensor errors... Low voltage errors can be noted just during cranking.

Re: system throws low gas pressure fault and wont manually switch untill high reducer temp

Posted: Mon Feb 11, 2019 9:15 pm
by Darren
Ok thinking about it that actually makes quite a lot of sense for the pressure reading.

I think ill have a look at the solenoid anyways just for peace of mind, what in a setup would you be looking for to make a decision like that on fuel overlap? I will also post a few pictures of the program which are all before i changed the settings you have mentioned in your post.
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When i noticed the 2 bar spike for the first time it was indeed exactly how you described it so it shouldnt be a problem then?

Thought id throw in another E023 because you can never have enough data, also the idle model calibration box was not ticked and i have left it unticked for now after putting in the other settings you suggested.
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I've already backed it up to the 2014 version it was on but ill update it again if thatd be best.

Could it be possible that simply raising the turnover temp to around 30c could fix the problem?

And as of right now the ECU is running with the settings you have suggested, will have to wait till the morning or later on tonight to give them a test unfortunately. such a hassle having a cold start problem!

Re: system throws low gas pressure fault and wont manually switch untill high reducer temp

Posted: Tue Feb 12, 2019 8:22 am
by Darren
Got up this morning and it threw the error at me again.
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Got to work and switched the engine off for a few seconds and started it up, switching straight over to gas, was a little shakey with the switchover though.

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Sorry the images are quite bad, was trying to sort them out through my phone, will reupload them once i get home. http://imgur.com/gallery/MpQafPC

Re: system throws low gas pressure fault and wont manually switch untill high reducer temp

Posted: Tue Feb 12, 2019 10:39 am
by LPGC
It is seeming more and more likely that your immediate problem is a sticking solenoid. There are other aspects that won't help it switch to gas very well especially on a cold morning (though it should still switch and try to run on gas with those aspects effecting it) but if the solenoid is sticking shut it stands no chance of running on gas.

Can also see that it won't run on gas flat out above around 5500rpm. And it's probably calibrated rich for pinj's greater than 3ms though this could be effected depending on whether your engine's petrol pressure reg is referenced to manifold vacuum or to ducting between air filter and throttle body.

Re: system throws low gas pressure fault and wont manually switch untill high reducer temp

Posted: Tue Feb 12, 2019 11:09 am
by Darren
Okay will be taking apart the solenoid on the weekend and seeing how it is. Im not too sure hiw to fugure out where the pressure reg is referenced to. What are some key signs to show that a reducer would need a repair kit? Was thinking i might as well do that while im taking the solenoid off of the reducer but if it isnt obviously causing any problems or showing signs on wear ill save that for another time.