Cannot switch to LPG

Message
Author
evandavic
New member
Posts: 9
Joined: Sun Feb 17, 2019 1:36 pm

Cannot switch to LPG

#1 Post by evandavic » Sun Feb 17, 2019 2:02 pm

Hi all,

I own a Chevrolet Evanda LPG 2.0l MY2005. Not a very common model though. I'm not very familiar with LPG cars, it's my first one I've got from my brother. He didn't use LPG at all.

The LPG switch near the gear shift is blinking from red to orange. The car documentation of the LPG system states it's waiting to switch to LPG, but it keeps blinking forever.
It's a NECAM system. My mechanic says it's probably the pressure sensor, but not sure. Could you please help me identifying the different parts of the system and give some tips to test them?

https://imgur.com/a/K7gxDrl

Thanks a lot!

Gilbertd
Advanced Member
Posts: 8049
Joined: Wed Apr 09, 2008 10:00 am
Location: Peterborough

Re: Cannot switch to LPG

#2 Post by Gilbertd » Sun Feb 17, 2019 3:18 pm

Does it have any gas in the tank? If it's waiting to change over but the tank is empty so it won't see any pressure, then it won't ever change.
'96 Saab 900XS, AEB Leo, sold
'93 Range Rover 4.2 LSE, Lovato LovEco, sold
'98 Ex-Police Range Rover 4.0, Singlepoint AEB Leo, my daily motor
'97 Range Rover 4.0SE, eGas multipoint, a project.....

Proud to be a member of the YCHJCYA2PDTHFH club.

Brian_H
Intermediate Member
Posts: 1207
Joined: Mon Jan 23, 2012 12:21 pm
Location: Milton Keynes

Re: Cannot switch to LPG

#3 Post by Brian_H » Sun Feb 17, 2019 6:07 pm

It might be the temperature sensor - this will be either directly screwed into the vapouriser (the bit shown in the first photo) or into a hose running to it, could be either. best bet with that is to locate it and check if the wiring to it is ok as a first step, If you can find it, then checking resistance of it might also help,though those systems usually switch over very quickly.

The pressure sensor is the bit on the you have labelled as a filter (it is also the filter though!)

I can't tell from the photos you've got if its the EGI or GSI system for sure, but would suspect its the GSI you have with injectors, rather than the EGI with the metering head arrangement, as there doesn't appear to be any sign of that bit of it. The presence of the pressure sensor also suggests to me that you have the GSI system. The EGI would switch even if there wasn't pressure there, and then timeout when seeing lack of o2 sensor movement. Don't know on the GSI, but would suspect that does sense pressure.

How quickly is the light flashing on the switch?

As far as your other parts are concerned, the box next to the tank (the grey/silver one) is the gas tight housing that covers the valves on the tank, if you unscrew the thumbscrew in the centre you can remove the lid to access the valves etc (it might be worth doing that to see what the gauge on the tank reads if your unsure how much is in there). Put it back on when your using the car though.

Autogas2000 have some stock of bits as well - might be worth a look there to identify bits you can't identify

https://www.autogasshop.co.uk/necam-kol ... s-35-c.asp

No idea if your install would use the rpm filters, but those can and do fail occasionally, Though i think those will cause a solid light normally rather than failing to change over.

evandavic
New member
Posts: 9
Joined: Sun Feb 17, 2019 1:36 pm

Re: Cannot switch to LPG

#4 Post by evandavic » Mon Feb 18, 2019 9:37 am

Hi,

Thanks for your answers :D

I filled with around 5 gallons (around 23 liters) and for sure the tank is 3/4 full as you can see in the video:

https://imgur.com/a/drLyoDl

The light is blinking from red to orange roughly every 1/2 second. I don't know what is the difference between GSI and EGI. The vapouriser, I can spot on the photos, is a Necam Mega if this helps. I can see also that one of the gaz pipes is cracked :(

I will for sure unscrew the lid of the tank and post photos.

Now, how is it possible to test both sensors? How to safely cut the gaz feed? From the tank?

Again, thanks again for your help!

Brian_H
Intermediate Member
Posts: 1207
Joined: Mon Jan 23, 2012 12:21 pm
Location: Milton Keynes

Re: Cannot switch to LPG

#5 Post by Brian_H » Mon Feb 18, 2019 11:08 am

That does actually look like its detected an error I think.

The pipe you can see split on the photos is a vacuum pipe - no gas there (unless the vapouriser is leaking, and even if it is there won't be much there and no pressure contained), A new bit of vacuum pipe will sort that bit, it won't be that causing your problem though.

I'll be home later, once i get chance will see if i can locate the fault code readout (seem to remember you connect a grey wire at the ecu to earth).

Pressure sensor very difficult to test, but doubt its failed at this point. Temp sensor once you find it, unplug it and check resistance (if you want to be really thorough check it when its cold and warmed up).

Other thing that might cause it is if either solenoid coil has broken - again unplug them, your looking for a resistance around 16 ohms across them (could be wiring running to them thats the problem as well). Can you hear either solenoid click like it tries to change over?

Brian_H
Intermediate Member
Posts: 1207
Joined: Mon Jan 23, 2012 12:21 pm
Location: Milton Keynes

Re: Cannot switch to LPG

#6 Post by Brian_H » Mon Feb 18, 2019 1:53 pm

Copying and pasting the diagnostic info - might or might not help (I've pasted it as I got it originally, so some of the language hasn't translated perfectly). I have some memory that the wire might not really be behind the switch in all cases, I think you can find it somewhere near either the fuses for the system, or the ecu itself (this may be somewhere inside the car, mine was in the drivers footwell but that was a Mondeo, yours could be anywhere near the engine area).

I've got a load of other info from what was uploaded by Pjpj here, I will send you a link to it, can't guarantee how helpful it will be though.

Read out diagnostic system for Koltec EGI / GSI.
De EGI LPG installation from Koltec has a self diagnostic-system which all disturbances will
be storages in its memory for a time.
When you have a problem whit the LPG installation, the first you have to do is read out this
memory.
This prevents expensive repairs, because the most auto mechanicals don’t have knowledge for
LPG installations.
Read out this memory is not difficult, and you don’t need expensive tools.
Behind de switch for choosing LPG / petrol is a grey wire whit a connector which is not
connected.
This wire has to be extended whit a other wire and connected whit the earth (chassis) of the
car.
Then you turn on the car key till all light bulbs in the dashboard go on all but don’t start the
engine.
The light bulb in the LPG/petrol switch goes flashing now.
This flashing is the giving the disturbances if there are.
Example1: 1x flashing, waiting a moment and then 2x flashing behind each other is code 12 =
no turning signal for the engine.
Note: This code is correct because we didn’t start the engine.(just at older types > 1995)
Example2: 4x flashing, waiting a moment and then 5x flashing behind each other is code 45 =
Gas mixture to rich.
Note: this code is coming often if the Vaporiser needs revision.
The diaphragms leaking and the Vaporiser/ pressure regulator don’t working well.
Every code will be given 3 times after each other before given a next code.
Codes which can be given:
Code 12 No turning signal for the engine (Vaporiser whitout temperature sensor)
(older type >1995)
Code 13 No Lambda sondesignal (lambdasonde or wiring is damaged)
Code 14 Temperature sensor signal to high.
(Vaporiser whit temperature sensor)(newer type 1995>)
Code 15 Temperature sensor signal to low.
(Vaporiser whit temperature sensor)(newer type 1995>)
Code 21 TPS-signal to high.(TPS = Throttle Position Sensor)
Code 22 TPS-signal to low.
Code 33 MAP-sensor signal to high.
Code 34 MAP-sensor signal to low.
Code 43 Divider/regulator don’t working.
Code 45 Gas mixture to rich.(light bulb in switch is flashing by driving the car)
When the gas mixture is to poor, the diagnose system gives no signal because it is thinking
the tank is (almost) empty.(light bulb in switch is flashing by driving the car)
If this is this is take a longer time, the system goes automatically to petrol run.
If the system is giving no disturbance code, and the light bulb in the switch doesn’t flash by
driving the car, the pressures don’t need to be checked.

evandavic
New member
Posts: 9
Joined: Sun Feb 17, 2019 1:36 pm

Re: Cannot switch to LPG

#7 Post by evandavic » Mon Feb 18, 2019 8:14 pm

Hi Brian,

Does this grey connector normally hidden from the dashboard? I mean I need to remove it to gain access to the connector?

Brian_H
Intermediate Member
Posts: 1207
Joined: Mon Jan 23, 2012 12:21 pm
Location: Milton Keynes

Re: Cannot switch to LPG

#8 Post by Brian_H » Mon Feb 18, 2019 11:11 pm

Well in your case its in the gearstick area - it should be behind the switch if the instructions are correct. As I said above, I have some vague memory of others reporting to only be able to find it at the fuse box end so it seems it may vary (your installed vehicle is going to be an unusual one as the majority of the Necam systems went into Vauxhalls, so may be a case of searching for it).

Does it keep flashing at exactly the same rate, or does it seem to do any sort of pattern? The video you posted before to me doesn't look like its waiting to switch over, more like its detecting an error of some sort (and if someone has tried to fix it previously they may have left the link wire in place when they gave up?)

LPGC
Installer
Posts: 3346
Joined: Wed Sep 29, 2010 6:01 pm
Location: Yorkshire
Contact:

Re: Cannot switch to LPG

#9 Post by LPGC » Tue Feb 19, 2019 11:30 am

The most common issues I find on Necam Koltec systems are (probably in this order) - solenoids, springs gone soft in reducer (lower than should be working pressure), failed metering units (gas distributor) on EGI / failed injectors on SGI, failed reducer (diaphragm etc), failed 'black box' (lambda emulation and signal switching unit on Vauxhalls), failed rpm module (Fords), failed sensors such as temp / pressure sensors, failed relays (Fords).

Few more hints and tips in case you don't find this grey wire...

First things first, does the reducer get hot? If it doesn't get hot due to a water flow problem it will never switch to gas.

Solenoids are easily tested. If solenoids are good but the system never attempts to open them (even after many engine restarts, battery been off for an hour, pressing the button etc) it points to an electronic component having gone down (but obviously not a solenoid because you tested them already) such as a sensor or module.
On EGI there is another solenoid on the gas distributor, if that's broken or stuck then when the engine attempts to run on gas it will almost die from fuel starvation until it switches back to petrol.
On EGI if you've got gas pressure anywhere near correct, that other solenoid also opens but the engine still won't run on gas it could be due to a failed stepper motor on the gas distributor (particularly if the engine only wants to run at a certain rpm/load), the plunger that the stepper motor controls can even break off the stepper motor shaft / threads can wear out.
On EGI and SGI if the engine seems to run relatively OK on gas but after a short time the light starts flicking because it's switched back to petrol a likely issue is incorrect reducer pressure (due to soft spring).
On SGI if it manages to switch to gas but misfires on a cylinder it's likely the injector on the misfiring cylinder is broken.

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

evandavic
New member
Posts: 9
Joined: Sun Feb 17, 2019 1:36 pm

Re: Cannot switch to LPG

#10 Post by evandavic » Sun Feb 24, 2019 5:44 pm

Hi all,

Thanks for your tips. Sorry for replying late, but was so busy.

I tried to take more detailed photos here:

https://imgur.com/a/S6Z316I

Do you think to grey/black cable from the switch is the grey one to get an error code from?

Again, thanks a lot for your help.

Brian_H
Intermediate Member
Posts: 1207
Joined: Mon Jan 23, 2012 12:21 pm
Location: Milton Keynes

Re: Cannot switch to LPG

#11 Post by Brian_H » Sun Feb 24, 2019 6:59 pm

From what I gather its usually the case that the cable isn't connected to anything at all under normal conditions. Don't think its at the switch on yours.
The grey cable looks to be on the second connector on the third picture (the one with the fusebox behind)

The tank solenoid is the grey thing in the first picture on the lefthand side (specifically thats the electrical coil used to operate it, the solenoid post sits inside it).
The other solenoid is the one that looks like it, on the bit next to the evaporator shown in your sixth photo. The black plug next to it plugged into the evaporator is your temperature sensor, I'd check that for resistance if you can (it will unscrew if that makes it easier, but its into the coolant so you will find that will run out of the hole if unscrewed). Check the wires running to it as well for any obvious damage if you can, including the connector.

No idea what the item in the 4th photo actually is, never seen one of them before, but suspect it looks like a metering head motor just different to what i have seen, suggesting you have a EGI system to me. Hopefully Simon can advise on that bit, Can you see where the gas lines connect to the manifold and either take photos of how they connect or identify them as injectors (will have wires running to them) or a black plastic cap (just a one way valve with no electrical connections) . This should tell what type of system it is.

Level is showing about 1/2 a tank full, I'd be inclined to try and check if any power is going to the front or rear solenoids, if its going to one but not the other then it won't see any pressure, so won't try and switch, Equally if either one doesn't work but is getting power, then the pressure sensor isn't going to see any pressure and won't attempt to switch over. Would be useful to know what you find to advise any further.

evandavic
New member
Posts: 9
Joined: Sun Feb 17, 2019 1:36 pm

Re: Cannot switch to LPG

#12 Post by evandavic » Sun Feb 24, 2019 7:16 pm

@Brian_H,

To test the solenoids, is it enough to just check for 12V at black/red cables? Easy for the rear one but the front one next to the temp sensor is very cumbersome to test. It's located under to metal panel which supports the battery, and even when the battery is removed, it's under the metal stand and not easily reachable. But I can maybe get access to the connector from the front of the car.

Brian_H
Intermediate Member
Posts: 1207
Joined: Mon Jan 23, 2012 12:21 pm
Location: Milton Keynes

Re: Cannot switch to LPG

#13 Post by Brian_H » Sun Feb 24, 2019 11:36 pm

That would tell you if its trying to switch at least - a better test is to put a 21w bulb in circuit and see if it lights up. Better still is to remove the coil (undo the small bolt on the top of it) and check for resistance across it. I'd suspect if you can't hear either of them clicking/clunking that either one has gone short circuit and stopping either from opening, or its not trying to switch in the first place.

The front one is more likely to be the problem as its exposed to the outside, unlike the tank one.

evandavic
New member
Posts: 9
Joined: Sun Feb 17, 2019 1:36 pm

Re: Cannot switch to LPG

#14 Post by evandavic » Mon Feb 25, 2019 1:01 pm

What I can do to hear the solenoid click sound is to disconnect the + lead and then plug it back. I probably need to turn the key to On without starting the engine right?

Brian_H
Intermediate Member
Posts: 1207
Joined: Mon Jan 23, 2012 12:21 pm
Location: Milton Keynes

Re: Cannot switch to LPG

#15 Post by Brian_H » Tue Feb 26, 2019 7:02 pm

Unless the system has tried to switch (and I'd suspect it hasn't at this point) the power won't be there to try. Easier to just disconnect it and put 12v to each solenoid directly if you can, Though I'd try testing both coils and the temp sensor on the evaporator first to see if something obvious is wrong, as it doesn't even look like its trying to switch to me.

evandavic
New member
Posts: 9
Joined: Sun Feb 17, 2019 1:36 pm

Re: Cannot switch to LPG

#16 Post by evandavic » Thu Feb 28, 2019 8:50 am

I'll try today the grey cable and to test both solenoids. For the rear one, can I just unscrew it to move it near the battery? For the pressure & temp sensor, is there a way to test?

Brian_H
Intermediate Member
Posts: 1207
Joined: Mon Jan 23, 2012 12:21 pm
Location: Milton Keynes

Re: Cannot switch to LPG

#17 Post by Brian_H » Thu Feb 28, 2019 9:51 am

Temp sensor use a multimeter set to resistance or ohms setting.

Coil yes, just make sure you leave the metal post under it on the valve else you will let the contents of the tank out
Pressure sensor not sure, suggest best bet is to see if any pressure is there, if not rule out sensor for now

evandavic
New member
Posts: 9
Joined: Sun Feb 17, 2019 1:36 pm

Re: Cannot switch to LPG

#18 Post by evandavic » Thu Feb 28, 2019 6:10 pm

Today, at my surprise, I took a ride for 15 mn and then at idle, switched to LPG and it worked about 1 mn and then stalled and didn't work again.

Then, I tested today the grey wire connected to the chassis. Turn key on without starting, but none of the leds where on. I thought something went wrong, I unplugged the minus battery lead for about 1 mn.

Then back again, now the LPG switch is always orange without blinking, meaning LPG works. When I switch back and forth from petrol to LPG, I can hear the click sound from the front solenoid. I recorded the sound of the rear one with my phone and it also works.

I drove the car for about 10 mn full LPG and it still works. It's a mystery.

Brian_H
Intermediate Member
Posts: 1207
Joined: Mon Jan 23, 2012 12:21 pm
Location: Milton Keynes

Re: Cannot switch to LPG

#19 Post by Brian_H » Thu Feb 28, 2019 6:23 pm

It's possible you have either a bad connection or sticky solenoid. Keep an eye on it, if it plays up again it might be an idea to clean the solenoid posts particularly the front one, they do sometimes end up with debris stuck in there stopping it switching. Though wiring just as likely given the age of what your dealing with.

I dont think its unknown for the necam ecus to need the power disconnecting from them to reset them as such occasionally either. But looks like good news at the minute.

evandavic
New member
Posts: 9
Joined: Sun Feb 17, 2019 1:36 pm

Re: Cannot switch to LPG

#20 Post by evandavic » Tue Mar 12, 2019 3:55 pm

Hi Brian,

After using the vehicle a whole week, it's very erratic. It switches 50% of the time. When it doesn't work the very first time, I have to try again at least 10 times, and then suddenly it works. Then, sometimes it cuts in the middle at the highway.
I thought the solenoid is kept open once it clicks. Is it possible it cuts off when functioning?

I also noticed when LPG is on, that sometimes the car has some hiccups generally at low speed, as if it was choking. Maybe it's related.

Anyway I'll try to take it out next time. Is it safe to take the front solenoid off of the car? Same for the pressure sensor?

Post Reply