Vectra LPG Duffer Part 3, Please HELP, ECU warning P0170 mixture too rich

After experinacing a few problems documented in here at a cost of almost £300 I have had fixed or replaced :

The costs were met by the sellar who is a car trader.

However after all these fixes and diagnostics I still get a ecu light coming on!

The reading given is: P0170: mixture Rich.

This usually comes on after 100 miles after reseting the previous P0170 code.

The reading from the exhaust lambda is bang on 1.0 (ie perfect). The O2 bank is switching between 0.2volts and 0.8volts (this again i am told by the mechanic is spot-on) he cant fully explain the problem.

The mechanic who is no gas expert believes the problem is a minor glitch when switching between petrol and GAS the car seems to get confused and there is nothing to worry about.

Fuel efficency on petrol seems OK. But on GAS im getting 4 miles to the litre.

On gas i have noticed a reluctance for the car to move especially when switching gears, i have to push the accelarator a bit more to make it a smooth transition between gears. Even a small (what appered to me, and i'm a little ignorant) backfire. The light seems to come on around the time i turn on the iginition, or when im driving at random.

Its costs the sellar a fortune should I hand the car back to the trader? or should I carry on? As always any help for the actual mechanical / electrical problem is welcome.

Weigh it in boy.

Sounds like the factory fitted LPG is a bodge. They should have re written the ECU to do both (just another set of lookup tables?), rather than bodging the LPG ECU to fool the petrol ECU into thinking the world is running fine.

Bob

Vauxhall build the cars and then transport them to a company called Millbrook who install the LPG systems. Most companies do it this way - build car first and then add LPG. I guess it isn't cost effective to tool up a production line to build LPG vehicles cos of all the different models involved. Vauxhall do build a Zafira that is gas first and petrol second but that is compressed natural gas (same as your house) not LPG. Never seen one but lots in Europe I am told - has 4 huge gas bottles under the floor as tanks.

"> Vauxhall do build a Zafira that is gas first and petrol second but that is

Really? I never knew that. does that mean that dual fuel zafs are vitually non existant here in the uk because of lack of refuelling facilities?

Mike

BTW, I do remember -trying to stay a bit on topic for the thread- that the guy who did my first ever lpg conversion (range rover) had just finished a

Mike

Lots of LPG Zafiras but never seen a CNG one yet - or any where to fill one. Some council - can't remember which - had a couple of CNG Combo vans as a pilot scheme test but filling time was 8hrs so it never caught on. They must have overcome filling time problems in Europe or you would be sat at filling stations all day. Vauxhall raced a 2.5 V6 Vectra B on LPG for a while but have never had anything bigger than 1.8 in production models

If it is natural gas, I would think you get a compressor fitted in your garage, and leave it connected to the gas mains overnight.

Bob

Now I think about it, I do believe I've seen a couple of CNG artics up and down the motorways. they do say CNG, not LPG. by accounts i've heard, drivers dont like them. something about overheating, but I've never drivenone myself.

Mike