Cut out LPG, long time to recover

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Cichaczech
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Cut out LPG, long time to recover

#1 Post by Cichaczech » Fri Jun 05, 2020 10:46 am

Hello

I have problem with system Tartarini in Fiat punto mk2 1.2 8V installed 9 years ago.
Problem: sometimes in acceleration or quick turn LPG system cuts out. (blue led slowly blinking, orange led is on). To switch back to LPG I have to revers or hard break :D and sometimes it wont switch to lpg at all.

Sometimes blue led just starts fast blinking but wont switch to LPG.
And with running on Gasoline and acceleration (5 or more sec. ) or hill drive the tartarini LPG LED display completly turns black without any sound effect (all leds off) and restarts after throttle release.

carried out maintenance:
new reductor and injectors 40 000km ago

resoldered cables (gasoline injectors/lpg signal?) one was completly oxidized and after resolder, lpg cut out almost disappeared ( before that lpg did not even switch on)

New lpg ecu Evo 01

new solenoids, Reductor and toroid tank

And visited 2 "Best in town" LPG services but nobody know what is wrong.
Thank you :)
Last edited by Cichaczech on Fri Jun 05, 2020 5:35 pm, edited 2 times in total.

Brian_H
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Re: Cut out LPG, long time to recover

#2 Post by Brian_H » Fri Jun 05, 2020 12:00 pm

There is an inline fuse on the battery feed to the ECU, typically the red cable. Pull out that fuse and check the fuse and holder for corrosion if you haven't already. Check the fuse is tight in the contacts as well.

Only things that should cause the panel to die and the rest of the system with it would be a dodgy connection to the switch, lack of ground or either of the live connections or a problem with either the loom (damage) or ECU itself.

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Re: Cut out LPG, long time to recover

#3 Post by Cichaczech » Fri Jun 05, 2020 3:27 pm

Yes I forgot. I also cleaned all connectors (alternator/battery/fuse box and all grounding points with resonably good acess), fuses and relays in fuse box (motor and passenger).

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Re: Cut out LPG, long time to recover

#4 Post by Cichaczech » Fri Jun 05, 2020 4:31 pm

I hope it is not the ECU again. It is 1 week old.

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Re: Cut out LPG, long time to recover

#5 Post by Brian_H » Fri Jun 05, 2020 4:44 pm

Do you have any access to the diagnostics for the lpg ECU? Are any faults being logged or do any readings look wrong when trying to run on gas?

You mention the ecu is new - is this the same loom being used? If so, that would suggest the loom is where the issue lies. If its dying completely as you suggest it is above, then its going to be down to a problem with either the ground/earth cable from the lpg loom (typically connected to a ground somewhere on the vehicle, possibly directly to the battery negative post), the permanent live (again fed typically from the battery directly in most cases, and will have an inline single fuse holder on the wire close to the battery - the one pointed towards above) and a second switched live, typically this is picked up from the petrol injector positive connection though can be picked up from any switched live circuit.

The switch panel itself may cause the same sort of issues, either due to it being not plugged in properly, a faulty panel or damage to the loom (melted against something or rubbed through by something close to it both possible causes)

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Re: Cut out LPG, long time to recover

#6 Post by Cichaczech » Sat Jun 06, 2020 5:41 pm

No I dont have access tartarini software. Technic said nothing about error codes, only information was that the ECU was not getting rpm signal and needs replacement. (I still have that old ECU in alu. box but I cant figure out how to connect to it. I made Rx Tx cable with TTL logic but PC keeps displaying that it cant connect, for the old ECUs software you don have to have the USB dongle i think)

Today changed spark plugs, resolder whole LED display and tried to find any loom demage but everything seems ok.
After that I started engin and let it idle for a while and it switched to lpg (in idle 850 rpm) so I turn off engine and started again and LPG never run again :( blue led slowly blinking and with full throttle all leds goes out.

Probably it is time to buy new car :)

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Re: Cut out LPG, long time to recover

#7 Post by Brian_H » Sat Jun 06, 2020 6:21 pm

Sounds to me like theres still an issue with the rpm detection. If this worked on the old ecu, that would suggest either that bit of the ecu has failed, or the loom isn't getting a good signal.

Bear in mind you need the matching version of software to connect to the ecu, and some may require later software due to the firmware loaded on them. Various options for software on https://projekt-tech.com/diagnostic-programs-pm-23.html

I'd suspect the rpm signal is still the problem though, and wasn't the ecu causing it (more likely either damage to the loom, or the pickup point isn't very well connected). Do you know where the rpm pickup is connected to? The timing out would suggest its seeing a signal at first then losing it for some reason (shorting to ground being very possible in that state).

There are various diagrams around for making the cable up - one of them is in this thread viewtopic.php?f=28&t=11428&p=90866&hilit=lead#p90866

Your best bet would be to get connected to the ecu somehow and see what you can then see. Bear in mind also that the ecu has to be powered up to connect (switched and permanent live connected with ground, so the panel should come to life).

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Re: Cut out LPG, long time to recover

#8 Post by Cichaczech » Tue Jun 30, 2020 11:13 am

quick update.

Last week I changed both wire harness and LPG pressure sensor. Problem still persist (whole almost new LPG system is instaled).
Later that day I found out that when heater blower is on max LPG works as new. When the fan is Off or on first 3 speeds LPG cuts out -> switch blower on max and lpg immediately switches on.

Brian Thanky you for all your responses. :)

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Re: Cut out LPG, long time to recover

#9 Post by LPGC » Tue Jun 30, 2020 11:21 am

If it works OK with one heater setting but doesn't work OK with different heater settings it may be that the reducer isn't plumbed to heater water correctly, the circumstances point to lack of hot water flowing through the reducer when the heater is set low.
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Re: Cut out LPG, long time to recover

#10 Post by Gilbertd » Tue Jun 30, 2020 1:37 pm

Or for some reason the LPG system is picking up the ignition switched supply from the heater blower circuit? That might explain why the switch suddenly goes out if the power supply is not good.
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Re: Cut out LPG, long time to recover

#11 Post by Cichaczech » Tue Jun 30, 2020 3:06 pm

Next update :)

Today is typical summer hot weather and max fan speed is not enouhg and lpg keeps cutting out. Switch AC on and route it on passengers or windscreen and it magicaly works. So it needs cooling for some reason. 🙄🙄

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Re: Cut out LPG, long time to recover

#12 Post by Brian_H » Tue Jun 30, 2020 3:17 pm

What Simon has said above. Start with how hot the reducer is getting, it should be hot if the engine is hot. If it's hot (test it by touching it directly) then what does the temp sensor shows in the software. If its not hot, then is it any different with the heater on full?

Is the drivers panel still going blank occasionally? Or has that been fixed?

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Re: Cut out LPG, long time to recover

#13 Post by Brian_H » Tue Jun 30, 2020 3:18 pm

And where is the switched positive wire actually connected to now?

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Re: Cut out LPG, long time to recover

#14 Post by LPGC » Tue Jun 30, 2020 5:08 pm

I did consider it could be a wiring issue related to the heater fan. It's possible the ignition switched live, permanent live are connected to the heater system.

If heater control settings effect reducer temperature at all then it's more likely: Any fan speed other than off will see the reducer get a flow of hot water (fan off means heater system off, hence if there's a solenoid controlling flow of water through the heater circuit it will close when the fan is off). A warm temperature setting will see the reducer more likely to get a flow of hot water than a cold (or especially full cold) temperature setting. Sometimes when fan speed is increased the temperature setting is also increased - with a low fan speed and AC on the car might not get too cold with the heater setting at full cold but with AC on and a high fan speed the car might get too cold unless the heat setting is also increased a bit.
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Re: Cut out LPG, long time to recover

#15 Post by Cichaczech » Tue Jun 30, 2020 7:16 pm

Brian_H wrote:
Tue Jun 30, 2020 3:17 pm

Is the drivers panel still going blank occasionally? Or has that been fixed?
yes, it still goes blank, but only after 10 - 15 sec of full or almost full throttle (long steep hill). After throttle release and cold air blowing, LPG switches almost instantly on.

Tomorrow I will check reducer temp and disp. connection.

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Re: Cut out LPG, long time to recover

#16 Post by Cichaczech » Wed Jul 01, 2020 4:14 pm

Cable from LPG panel goes directly to LPG ECU.
Reductor water hoases gets hot after while in idle ( no fan).
Selecting cold or hot air from panel selector has no influence on LPG.
Switching on AC helps LPG working. (Hot or cold air)
Driving from hill down with gear selected also heps LPG.

Conclusion: Could it be overtemperature problem?
AC on = Big front cooling fan ON
Driving downhill (no throttle) = cooling
Also problem with lpg started at summer.

But dashboard temp. stays allways perfectly in middle.

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Re: Cut out LPG, long time to recover

#17 Post by Gilbertd » Wed Jul 01, 2020 4:23 pm

More likely under temperature. You need to wait until it cuts out then check how hot, or not, the reducer is. If you can put your hand on it and keep it there, it isn't hot enough.

It's not how the switch is connected, it's where has the LPG system got it's power from. It will have two power feeds, a permanent, which wants to be connected via a fuse directly to the battery and an ignition switched which can be picked up from the common feed to the petrol injectors.
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Re: Cut out LPG, long time to recover

#18 Post by Cichaczech » Wed Jul 01, 2020 4:46 pm

Power source is exactly as you described (battery with fuse and one from injector). I resloder new harness and it goes straight from positive battery terminal and from injector directly to ECU.

Reducer is hot. More than quick touch any you get burned :) same as radiator pipes.

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Re: Cut out LPG, long time to recover

#19 Post by Brian_H » Thu Jul 02, 2020 12:37 am

What does the reducer temp sensor show on the software? Also worth checking the wires running to the sensor just it case they have started corroding away and are only making contact some of the time.

If the temp reading looks fine, it might be worth putting up some screenshots of the settings to see of anything else there could be causing it.

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Re: Cut out LPG, long time to recover

#20 Post by Cichaczech » Fri Jul 03, 2020 6:58 am

I cannot figure out, how to connect to LPG ECU. 🙄 I will borrow tartarini diagnostic somewhere.

Only thing I found yestarday is that lpg runs only morning (when outside temp is low) and cut out 20 min after engine warms up.
And when is outsite temp high or lpg cuts out it only switch back when radiator fan spins. Fan on - > LPG gas tank solenoid click and reductor solenoid click.

I mooved all looms away from every Fan wire so no induction is possible, but still fan controls lpg.

And car ECU report 2 errors with too rich mixture ( at water temp 89) . Probably when lpg switch back to gasoline.

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