Lpg gurus

Robti · 29th July 2015, 08:49

Hi brothers system keeps jumping back to petrol from gas, what determines when the system should switch over to lpg.

Only other thing in case it's related is that no heat from the matrix and no coolant only water in expansion tank( getting refilled with oat today)

Greeners · 29th July 2015, 16:17

The system relies on the coolant temperature to switch from petrol to gas.

If you hace low coolant / air in the system then the sensor will get false readings.

More worrying is the damage you'll do with a defective cooling system

marinabrian · 29th July 2015, 16:46

Quote:

Originally Posted by Greeners

The system relies on the coolant temperature to switch from petrol to gas.

If you hace low coolant / air in the system then the sensor will get false readings.

More worrying is the damage you'll do with a defective cooling system

No airlocks or low coolant in this particular car

Brian

Greeners · 29th July 2015, 16:47

Quote:

Originally Posted by marinabrian

No airlocks or low coolant in this particular car

Brian

Before or after his LPG problems Bri ?

marinabrian · 29th July 2015, 17:18

Quote:

Originally Posted by Greeners

Before or after his LPG problems Bri ?

Both, the car was fitted with LPG when bought by a certified LPGA fitter, and there has been no coolant loss or wild variations in coolant temperature

minimutly · 29th July 2015, 18:51

Hi brothers system keeps jumping back to petrol from gas, what determines when the system should switch over to lpg.

Only other thing in case it's related is that no heat from the matrix and no coolant only water in expansion tank( getting refilled with oat today)

Either the cooling system works or doesnt?
If the heater matrix is cold its likely the vaporiser is also. This will switch it back to petrol.
I say likely, youd need to check, it could be tha matrix is blocked. Its also possible that the vaporiser is in parallel with the matrix, and there is no water flow through it - hence going back to petrol.
Im afraid you need to feel the vaporiser.....

Robti · 29th July 2015, 22:12

Dipped the coolant and no colour at all so thinking it's only water in it, also no heat in car when set to high, gauge sits at 9 o'clock steady so stripping matrix out tomorrow and flushing then refilling with 50% oat premixed before filling, to see if that helps with both problems

bignorry · 30th July 2015, 08:48

Apart from this niggle I would say this is one of my best value buys.

minimutly · 30th July 2015, 15:15

Stripping out the matrix?
Thats a bit ott utill you know it has an issue!
I would rmove the false bulkeads and plumb a hose in the line to see if you get flow first.
If you dont then carry on with removal. Is the vap in series? If its in series and the matrix is blocked then you have the culprit. If its in parallel then you have another problem....

Robti · 30th July 2015, 17:13

Well the water was drained( can't call it coolant ), the matrix flushed out and left with vinegar all day then re flushed till the crud stopped coming out, refilled with fresh coolant and now toasty feet( in fact he was complaining that it was only 14 outside but there was plenty of heat in the car ( had to explain how a 75 matrix works), so at least one problem solved and will see after a run tonight how the lpg performs, but the main one he was bothering about was the heater

29th July 2015, 08:49	#1
Robti Posted a thing or two MG ZT-T 190+,Rover 800 vitesse coupe Join Date: Aug 2014 Location: Hamilton Posts: 1,971 Thanks: 616 Thanked 228 Times in 210 Posts	Lpg gurus Hi brothers system keeps jumping back to petrol from gas, what determines when the system should switch over to lpg. Only other thing in case it's related is that no heat from the matrix and no coolant only water in expansion tank( getting refilled with oat today) __________________ Robert

29th July 2015, 16:17	#2
Greeners Moderator MG-ZTT Join Date: Mar 2007 Location: Ware, Herts Posts: 19,798 Thanks: 161 Thanked 1,249 Times in 1,036 Posts	The system relies on the coolant temperature to switch from petrol to gas. If you hace low coolant / air in the system then the sensor will get false readings. More worrying is the damage you'll do with a defective cooling system __________________ *David* Impecunity is the mother of ingenuity Useful how to's for common problems Car Of The Month Jan 2014 [SatNav Power Down] [Coolant Level] [SatNav Repair] [Diesel Non Starting] [Paint Codes] [Rear Light Seals] [Reversing Light Switch] [Bleeding Brakes][Sunroof Drain] [Early ZT's][Instrument Pack Diagnostics][ATC Diagnostics]

29th July 2015, 22:12	#7
Robti Posted a thing or two MG ZT-T 190+,Rover 800 vitesse coupe Join Date: Aug 2014 Location: Hamilton Posts: 1,971 Thanks: 616 Thanked 228 Times in 210 Posts	Dipped the coolant and no colour at all so thinking it's only water in it, also no heat in car when set to high, gauge sits at 9 o'clock steady so stripping matrix out tomorrow and flushing then refilling with 50% oat premixed before filling, to see if that helps with both problems __________________ Robert

30th July 2015, 17:13	#10
Robti Posted a thing or two MG ZT-T 190+,Rover 800 vitesse coupe Join Date: Aug 2014 Location: Hamilton Posts: 1,971 Thanks: 616 Thanked 228 Times in 210 Posts	Well the water was drained( can't call it coolant ), the matrix flushed out and left with vinegar all day then re flushed till the crud stopped coming out, refilled with fresh coolant and now toasty feet( in fact he was complaining that it was only 14 outside but there was plenty of heat in the car ( had to explain how a 75 matrix works), so at least one problem solved and will see after a run tonight how the lpg performs, but the main one he was bothering about was the heater __________________ Robert

29th July 2015, 18:51	#6
minimutly Posted a thing or two mg zt Join Date: Mar 2014 Location: cardigan Posts: 1,087 Thanks: 28 Thanked 187 Times in 158 Posts	Hi brothers system keeps jumping back to petrol from gas, what determines when the system should switch over to lpg. Only other thing in case it's related is that no heat from the matrix and no coolant only water in expansion tank( getting refilled with oat today) Either the cooling system works or doesnt? If the heater matrix is cold its likely the vaporiser is also. This will switch it back to petrol. I say likely, youd need to check, it could be tha matrix is blocked. Its also possible that the vaporiser is in parallel with the matrix, and there is no water flow through it - hence going back to petrol. Im afraid you need to feel the vaporiser.....

30th July 2015, 08:48	#8
bignorry Newbie MG-ZTT Join Date: Aug 2014 Location: Hamilton Posts: 15 Thanks: 6 Thanked 7 Times in 5 Posts	Apart from this niggle I would say this is one of my best value buys.

30th July 2015, 15:15	#9
minimutly Posted a thing or two mg zt Join Date: Mar 2014 Location: cardigan Posts: 1,087 Thanks: 28 Thanked 187 Times in 158 Posts	Stripping out the matrix? Thats a bit ott utill you know it has an issue! I would rmove the false bulkeads and plumb a hose in the line to see if you get flow first. If you dont then carry on with removal. Is the vap in series? If its in series and the matrix is blocked then you have the culprit. If its in parallel then you have another problem....