Best LPG Set-up for 1989 740 GL with B230F
 

I have been having continual problems with my LPG set up for my '89 740 GL. I ma looking for suggestions on systems that will suit my baby. A simple mixer and OMVL converter were installed. I have had some advice from members which I am acting on. I live in Australia where the LPG companies don't have a lot of interest in this type of vehicle. Some pictures of my set-up are attached.

Koule

Lpg
 

First of all whats the problem you are having with your LPG system [ a lot of folks blame the LPG when its not]
Your system is very simple and dosent often give trouble. [ Used similar although much older one 40 years ago , and its still running , with just the odd filter valve and diaphram change ]
Might be able to point you in the right direction ?
Hope this helps .
Regards
Mike B

The problems I'm having is inconsistent running. The idle is not stable. Acceleration can cause stalling. When on the analyser, it does not seem to be very stable. I had the converter pulled apart twice only to find treacle in it. It can't be the gas. My mechanic (the installer)has been scratching his head over this installation. It is not his bread and butter installation. He is methodical in his workmanship, however. I'm hoping the forum might be able to throw me another system that might run more smoothly

Your problems are all down to the installation. This system has not been fitted correctly and that is why you are having the issues.

The 3 big problems all stem from the location of the OMVL R90e reducer

1)To start with it is two cloase to the exhaust manifold and would not pass UK regulations like that. The unit will be slightly affected by the heat.

2)The pipe that takes the gas from the unit to the mixer is fitted to the wrong connector on the unit. The pipe should be fitted to the bottom unit to allow the oil to be sucked though and burnt off in the engine. ( this oil is totaly natural and is presant in all LPG and evry LPG installer should know that)

3) The vapouriser is to far away from teh mixer causing lag. The pipe length should be no more than 500mm


Beacuse you have AC fitted the reducer (omvl R90e) will not fit where I normaly put it. The best option in your case would be to remove the air box (this may also solve another problem) and fit a K@N style are filter onto the air flow meter. The R90 could then be mounted where the air box was located.

When using a mixer type system the hot air intake valve should be locked closed as LPG does not need the hot air when cold. The hot air actualy causes poor running.

Here is a pic of that unit mounted on a 740 with the mechanical K jet fuel injection system

http://i3.photobucket.com/albums/y82...ABCD0015-1.jpg

As I said previously on your car it will have to be mounted where the air box is.

As per phone conversation here are some pics of the injection system fitted to teh same engine as yours but in a 240. All the parts can be mounted in exactly the same positions. Sorry for the delay but I had changed my email address on my profile and this stopped me posting upto now.

Genral engine bay shot

http://i3.photobucket.com/albums/y82...e/ABCD0016.jpg

LPG injectors (note they are OMVL but I no longer recomend these)

http://i3.photobucket.com/albums/y82...e/ABCD0020.jpg

Position of LPG injector nozzle

http://i3.photobucket.com/albums/y82...e/ABCD0019.jpg

position of ecu and lpg reducer (between strut tower and bulkhead on RHS)

http://i3.photobucket.com/albums/y82...e/ABCD0018.jpg

http://i3.photobucket.com/albums/y82...e/ABCD0017.jpg

Thank you so much for all your information. It is a revelation. I spoke to someone about Volvo 740's and LPG systems here and they told me that a system overseas may not work in the same manner. I did not pursue the issue. 2 further points at this stage.
1. My Volvo has Motronic injection. Is this a problem with a sequential multipoint system?
2. What is a K@N style air filter? The mass airflow meter is electronic.

I'm new to this, having only just bought a 240 with a very similar conversion to yours.
But I have just learnt that it is very important that the pipe to the Idle Air Valve is downstream of the mixer. Yours is UPSTREAM, so surely it won't idle because the IAV is not getting any gas.
My understanding is you need a mixer with Idle air tapping, ie 2 pipe connections, one for gas, one for idle air.

The installer who did mine was aware of this, and cut the original plastic duct just behind the bit where the two hoses join, and then inserted a mixer just like yours upstream. But a proper 2-pipe mixer would be better.

LPG Mixer
 

On my 2.0 injection the mixer has two inlets , . It looks to me that your pipe that goes to your slow running valve is on the wrong side of the mixer were it wont recieve any gas , just fresh air. Where your slow running pipe branches off the air filter pipe , i have blocked mine off and resited mine to one of the inlets on the mixer collar. Which is in front of the gas inlet but behind the butterfly valve so that when it,s closed, gas saturated air diverts down to the slow running valve.

Work has been completed on my 740 wagon. I am now waiting for the gas installation which has been made infinitely easier by taking the air box out. Question about the filler end. Any recommendations for where the filler can be installed. My 740 sedan had in the petrol fill, which made it very neat and invisible. Is this possible in the wagon? Thank you.