I have recently purchased a Astra 1.6 estate auto that has an AG gas conversion, the engine runs OK. The problem is that I can only get 23 MPG on gas, I use the car for a mix of long and short jouneys. The Astra has just passed an MOT. Has anyone have any experience with AG systems that could help me find out what is wrong. I was hoping to get at least 30 MPG.

On or around Mon, 2 Oct 2006 12:01:40 +0100, oily jeans
enlightened us thusly:


I have recently purchased a Astra 1.6 estate auto that has an AG gas
conversion, the engine runs OK. The problem is that I can only get 23
MPG on gas, I use the car for a mix of long and short jouneys. The
Astra has just passed an MOT. Has anyone have any experience with AG
systems that could help me find out what is wrong. I was hoping to get
at least 30 MPG.

doesn't sound completely silly. what does it do on petrol, for the same
sort of driving?

rule of thumb - open loop systems should achieve about 80% of the petrol
mileage. Good, optimised closed loop should get nearer 90%.

If you're running petrol ignition timing, that will affect it. Depending on
what age car and type ignition system, it might benefit from adjusting it.
--
Austin Shackles. www.ddol-las.net my opinions are just that
"The great masses of the people ... will more easily fall victims to
a great lie than to a small one" Adolf Hitler (1889 - 1945)
from Mein Kampf, Ch 10

[quote=Austin Shackles]On or around Mon, 2 Oct 2006 12:01:40 +0100, oily jeans
enlightened us thusly:
[color=blue][i]


Thanks Austin, I have not tried an economy test on petrol. The Astra is a 2001 model and the LPG conversion was fitted some years ago

Hi Austin I have just complete a fuel economy test using petrol and the car did 34 MPG. This was what I was expecting, so I should be able to get about 30 MGP running on LPG. I did disconnect each fuel injector thinking one could be stuck open, but the engine misfired on each one. any suggestions Austin or anyone else help me please? oily jeans.

]

On or around Fri, 20 Oct 2006 15:59:44 +0100, oily jeans
enlightened us thusly:


Hi Austin I have just complete a fuel economy test using petrol and the
car did 34 MPG. This was what I was expecting, so I should be able to
get about 30 MGP running on LPG. I did disconnect each fuel injector
thinking one could be stuck open, but the engine misfired on each one.
any suggestions Austin or anyone else help me please? oily jeans.


need to know more about the LPG conversion to get any more sense. What type
of conversion:

single point? (mixer on the air inlet)

open loop? (no electronic controls)
closed loop? (electronic control with lambda sensor)

multi point? (4 separate gas injectors)

SGI? (sequential gas injection. often fitted to modern engines)

I'm not sure that you can have mutli-point without SGI.


--
Austin Shackles. www.ddol-las.net my opinions are just that
Soon shall thy arm, unconquered steam! afar Drag the slow barge, or
drive the rapid car; Or on wide-waving wings expanded bear the
flying chariot through the field of air.- Erasmus Darwin (1731-1802)