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[Derek_in_Penzance]

So.. back to my 1998 ex-eBay Omega 3.0 Elite auto estate with added LPG.

It passed the MOT on Friday! Oh happy day, after nearly two months of trauma with my exhaust manifold saga, ABS ECU saga, non-starting saga, replacing all metal brake lines for MOT saga, etc.

So I am now officially on the road and enjoying Omega motoring (with a gearbox problem -put a Snap-On Ethos diagnostic thing on it at the MOt place and it came up with Solenoid A electrical... but we'll deal with that later (all old fault codes were then reset). For the moment I can drive the car no problem as long as I stir the selector lever on the hills. I do have a replacement gearbox now, in case it really is worn out clutches etc.

But here is my latest question: doing a paperclip test, the engine management light blinks 13, lambda sensor 1 open circuit. This doesn't seem to affect running on petrol, at least not that I've noticed; the EML stays off.

However I think it is affecting runnning on LPG. The moment I switch to LPG, the EML starts blinking at me, at a fast rate, and the green LED on the LPG switch starts blinking too, more slowly. If I put my foot down to accelerate, the LED seems to go into half red, half green blinking. Take my foot off the pedal and cruise, and it goes back to green blinking. At no time does it stay non-blinking solid green all the time. However, the car seems to be running on LPG as the tank level is going down, also at idle the engine note changes quite noticeably as it switches over (slower and rougher idle on LPG).

I'm assuming that the suspect 02 sensor is affecting the LPG running more than the petrol, and the blinking EML and blinking green LED are warnings. Is this correct? I've read over on an LPG site that the LPG ECU rides piggyback on the petrol injection ECU, and if an O2 sensor goes duff the petrol ECU defaults to one of three safety readings. The LPG ECU doesn't seem to like this, hence the blinking. Am I right?

If I switch back to petrol, the EML lamp stays off. It only blinks rapidly when I switch to LPG.

I expect I could solve this by getting under the car and either replacing the O2 sensor or checking for a  bad plug contact, but I'm hoping one of you will say "oh yes, that's exactly what is happening", then I can save myself the trouble of pondering any other possible faults.

I don't know what make the LPG system is. It was installed in 2001 and the service notes say Sebelle. But I can't find that brand of system anywhere on the 'net. It is a sequential system and seems to run fine apart from the green blinking.

Postscriopt to previous pleas for help -I found out where the long vaxcuum pipe went, to a broken vacuum reservoir No 2 down on the air intake ducting. I've replaced it with one from a Senator stuffed under the scuttle, and also checked all the vacuum pipe connections thanks to the help and diagrams on the Maintenance section of this site. Brilliant help, thanks.  

[Derek_in_Penzance]

PS. Which of the two Lambda sensors is No 1? LH or RH downpipe? Thanks.

[Danny]

both my lambdas throw a fault code on LPG so i dont know which is which, runs perfect on petrol, but my LPG has many issues compared to yours

i cant help much but if you know what kind of kit it is, someone might be familiar with it, as my LPG doesnt flash any LEDs at me in any colour until the gas runs out!

edit: just noticed you said you dont know what system it is!

[philhoward]

Does blinking green imply that its out of LPG - or rather the ECU thinks it is?  On a lot of systems, red is for petrol running and green is LPG.  On mine, it has 3 modes -no LEDs, petrol; ramping up and down LEDs, waiting for changeover; when on LPG, the LEDs indicate the tank level.

It could be that yours is set to return to petrol under hard load?

Mine also has a Lambda emulation feature - chop the original cable and send it to and from the LPG ECU.  I'm not that brave (given its a current sink system), so just running it in parallel as far as the Lambda sensor goes.  Could your emulation not be working properly?If mine runs lean for too long (like during the calibration this morning) the EML light comes on, though!  Normal running it seems happy enough.

Assuming its a multi point system - are all the solenoids working?  If one on the 1st bank was playing up then this would send the mixture VERY weak.

[Derek_in_Penzance]

Thanks for your suggestions (and any yet to come!) I will have a look tomorrow Sunday and also take some photos.

But as far as my little LPG switch is concerned, it is just a rocker
switch with a big red LED for out of gas (goes off when on petrol), a big green LED (occasionally half red or all red) for running on gas, and in between four small bright green LEDs for approximate LPG fuel level in tank.  

When running on LPG properly, the big green LED should light up permanently. When switching to petrol, all LEDs go out.

[rickyboy]

What kind of system do you have?  My lpg fuel indicator flashes slow when there is a fault with the lambda - either electrical or mixture faults.  Looks like you need a either a re-map of the software because the mixture is out or you may have a loose connection somewhere.  

[Omegatoy]

that sounds like an early system in ,that the big led is powered by the lambda control and the red and green indicates best economy when green ,and rich under load when red, obviously it flickers up and down the scale as the engine revs, on the early ones it was red under full bore and slowly backed off to green under cruising conditions,then when on a steady cruise the indicator used to genlty waft up and down the scale as the lambda switches the fuel mixture,
does that make sense?
Omegatoy

[Derek_in_Penzance]

The rapidly blinking EML has gone; that turned out top be related to a broken brown/blue O2 sensor wire where the LPG converters had tapped into it. When fixing my ABS ECU I must have disturbed it and it broke. That was what the fault code 13 Lambda sensor No 1 open circuit was all about.

But my green gas light is still blinking, so I guess there is another fault that I have to locate. Looks like I will have to check the whole LPG wiring loom, ECU, emulator etc.

But we're slowly getting there!

[Taxi_Driver]

My lights flash when it switched to lpg but running on petrol.....might not be out of lpg........just its switched back to petrol.....either thinks its got problem or as Phil says could be configured to switch to petrol under hard load.

If it is switch ing back to petrol.......could be number of reasons.....low gas pressure.....no vac at the vapouriser.....is the vap getting really hot??

[Derek_in_Penzance]

Exciting update -EVERYTHING WORKS!

Yes indeedee, including the auto gearbox.

I went on a 60-mile trip this evening and the green LED stopped blinking and stayed on. So I was running on LPG, no problem. I was amazed to find that the auto gearbox, that had been acting as if it was worn out, is now miraculously cured and works perfectly (as far as I can tell).

It does take rather longer to switch onto LPG than I think is right though. I stopped briefly by a cash machine, and it was a mile and a half before it switched fully onto LPG again. So although it si working the switchover seems a bit lethargic. More work to there I think. Would that be the vapouriser not getting up to temp quick enough?

All I have to do now is replace the broken vacuum solenoid valve down by the crank pulley/back of multiram ducting, to restore full multiram operation,. and my car should be running nigh on perfectly.

Needless to say, I am thrilled to bits, after all the heartache and difficult working conditions in the crowded V6 engine bay.

[Derek_in_Penzance]

(1998 3.0 Elite estate + LPG)

Out again today, pondering the rather slow switchover to LPG. Put my foot down and "click" I hear the valve go in the tank behind me, and light is solid green. So it seems that the system needs me to give it a bit of mild welly before switching over, rather than my must-save-petrol pussyfooting around!

So it seems that once it is up to temperature, it also needs the pedal depressed to make it switch over. Interesting. Anyway, it all seems to run fine, so I am at last feeling rather positive about my "bargain" eBay shed. I like the colour (metallic green), I like the light greyish leather interior, I like the performance (so far, as the multi-ram system needs a  replacement solenoid before it will really motor), I like the capacious estate body, I like the ride and handling, and I like the toys. Even the rather antiquated sat nav works really well. It got me home anyway! I especially like the price of LPG.

Why the broken Lambda wire affected the auto gearbox I have no idea, but it did. It works perfectly now. Next job will be a cambelt change as it is due about now and if I push my luck I fear a damaged engine.

PS I can see an LPG conversion on my Monza coming up.    

[philhoward]

I suspect the "welly" switch is actually an RPM threshold - most systems won't changeover until they reach 2000rpm AND deccelerating AND vapouriser up to temperature...Yours might be set a bit higher, being an Auto (what RPM does it change gear on your normal driving pattern?).  This sort of makes it a deliberate changeover to LPG, rather than it choosing, so giving you some control over it.  Stands a chance that the "S" button would have had the same effect!

[Derek_in_Penzance]

I suspect the "welly" switch is actually an RPM threshold - most systems won't changeover until they reach 2000rpm AND deccelerating AND vapouriser up to temperature...Yours might be set a bit higher, being an Auto (what RPM does it change gear on your normal driving pattern?).  This sort of makes it a deliberate changeover to LPG, rather than it choosing, so giving you some control over it.  Stands a chance that the "S" button would have had the same effect!

Thanks, yes that makes sense. I'll see how it goes over the next few days. I am very new to all of this and it's been a bit of a challenge, to say the least, but without the help and advice of OOF members I'd probably still be struggling and wondering why my speedo doesn't work....thanks everybody.