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[Taxi_Driver]

Not my Omega......tho thats not well either  

The veccyB......

Bit of history.....its been for a couple of months only running on 3 cylinders on petrol.....on lpg its been fine....so havent been too fussed in fixing it....ive been suspecting a petrol injector is knackered....no3 one i reckon from the ecu codes.

Anyway it came back on Friday for missing underload on lpg.....i tried it and it did 'cough' now and then running on lpg.....i changed the plugs....made no difference...so changed the coil pack....this seemed to fix it   (This will be the 2nd coil pack its had since ive owned it)

Anyway friday night it cut out running on lpg.....and refused to restart (on petrol)
1/2 hour later it started on petrol....altho running on 3 cylinders....then few secs later switched to lpg no probs and carried on running fine the rest of the night.

Tonight its done it again  ......cut out running on lpg and refusing to start on petrol....engine just turns over.....was with it about an hour trying to get it to start.....but no luck tonight   So ive just locked it up and left it at the side of the road!  

To me this sounds like an ignition prob?  :-/

But things i did notice tonight.....EML doesnt come with ign on? it does on my omega and goes off as soon as it starts. Also with ign on the lpg light doesnt flash to indicate its on petrol.....it just glows a bit??

Im going back to it in the morning with the old coil pack just in case the 'new' one I fitted yesterday has gone bye byes.
Also gonna take my laptop to see if ecu has recorded any fault codes to give a clue.

But after that im a bit stuck.....not sure what to check after that.....apart from fuses (but did check the 'big' fuses in the engine comp tonight....none of them have gone)

Its DBW on this vectra.....if that helps. It has got some petrol in it i think.....(which was my 1st thought!) the petrol guage moves to the top of the red.....but i would have thought it would stink of petrol just turning over and not starting.....ie getting flooded

Think i might chuck another gallon in tommorow just to be sure

So any ideas peeps on what to check for.....i have another veccy 1.8 but its the VeccyC (same engine) but slightly different setup on lpg.....to rob parts off.

Cheers  

[hotel21]

Not got too much time now, TD, but you say 'engine just turns over' - how about when you add jump leads?  Start OK or the same probs?

Thinking alternator or battery, seeing how the car has quite a large load due to its use.  Get a meter on battery on idle and running.  

Would initially be looking for an earth (battery/engine block favourite - try a new seperate one with a spare jump lead) to start then get into the more technical options after ruling out fuel, good sparks etc....

B

[Taxi_Driver]

Not got too much time now, TD, but you say 'engine just turns over' - how about when you add jump leads?  Start OK or the same probs?

Thinking alternator or battery, seeing how the car has quite a large load due to its use.  Get a meter on battery on idle and running.  

Would initially be looking for an earth (battery/engine block favourite - try a new seperate one with a spare jump lead) to start then get into the more technical options after ruling out fuel, good sparks etc....

B

Sorry i meant it just turns over and doesnt start.....turning over is fine....new GO battery on it a while ago..... cranks really fast but wont start  

[Markjay]

The diagnostic routine from days of old was based on the engine needing three elements to start: fuel, spark, and compression. In those days it was easy, to check for fuel you simply took-off the pipe feeding the carb to see if it was squirting petrol when the engine is cranked, spark was tested by holding the HT lead near the engine body, and compression with a compression tester (or just putting you finger on the plug hole). Well there was obviously more to it, such as valve timing and ignition timing, but for basic diagnostics this was good enough.

Sadly I am not sure how this can be applied to modern engines... the spark is to risky to test being very high voltage, and you don't really know what the injectors are doing. Not to mention the various sensors... I suppose the way forward on a modern engine would be to check things in order of probability, e.g. firstly look for stored fault codes, then say crank sensor,. etc... would be nice if one of the knowledgeable chaps here could make a list of things that could stop the car from starting, in order of probability / common occurrence...

What I can contribute, is that if an auto car does not start and the starter will not run even though the battery is good, check the inhibitor switch in the auto box (the one that prevents the starter from running if the car is not in Park). Happened to me on my previous Omega... the proof was that the car could be started by bypassing the ignition switch with a long wire from the positive battery terminal directly to the starter solenoid.

Also, as far as I know immobiliser problem will mean that the starter is cranking the engine but the engine will not actually fire-up (due to fuel cut-off)?

[Nickbat]

But things i did notice tonight.....EML doesnt come with ign on? it does on my omega and goes off as soon as it starts. Also with ign on the lpg light doesnt flash to indicate its on petrol.....it just glows a bit??

As far as I know TD, lights don't just glow unless there's an electrical problem. Are you saying that, under normal cuircumstances, the LPG light would flash brightly? Sounds like maybe an earth or alternator problem.

[Taxi_Driver]

The diagnostic routine from days of old was based on the engine needing three elements to start: fuel, spark, and compression. In those days it was easy, to check for fuel you simply took-off the pipe feeding the carb to see if it was squirting petrol when the engine is cranked, spark was tested by holding the HT lead near the engine body, and compression with a compression tester (or just putting you finger on the plug hole). Well there was obviously more to it, such as valve timing and ignition timing, but for basic diagnostics this was good enough.

Sadly I am not sure how this can be applied to modern engines... the spark is to risky to test being very high voltage, and you don't really know what the injectors are doing. Not to mention the various sensors... I suppose the way forward on a modern engine would be to check things in order of probability, e.g. firstly look for stored fault codes, then say crank sensor,. etc... would be nice if one of the knowledgeable chaps here could make a list of things that could stop the car from starting, in order of probability / common occurrence...

What I can contribute, is that if an auto car does not start and the starter will not run even though the battery is good, check the inhibitor switch in the auto box (the one that prevents the starter from running if the car is not in Park). Happened to me on my previous Omega... the proof was that the car could be started by bypassing the ignition switch with a long wire from the positive battery terminal directly to the starter solenoid.

Also, as far as I know immobiliser problem will mean that the starter is cranking the engine but the engine will not actually fire-up (due to fuel cut-off)?

Thanks for your input MJ  

Tho Veccy is manual.....so wouldnt cause a prob starting....i did think about imobiliser but spanner light doesnt flash as it should with that fault....but just to check i have a spare key for that veccy so will take it the morning just to double check  

Crank sensor......did cross my mind as well......tho dont know if that will stop a veccy from starting....hopefully if it is a sensor then when i read the codes it will show up  

[Markjay]

Incidentally... not directly related, but I heard a story today from a guy that use to work for Prodrive (the Subaru tuners), apparently 7 years ago there was a huge rise in Impreza theft, and the insurance companies could not figure out how they thieves managed overcome the immobiliser. One day the police turned-up at Prodrive with an ECU and an ignition barrel that they found at the house of a suspect, and asked them engineers to see if they could start one of their cars by swapping the ECU and ignition barrel. They swapped it on one of their own cars, it took 10 minutes and the car was driven away. So the police thinks that the thieves had pre-programmed matching ECU and ignition barrel sets, and they broke into cars and swapped them.

Also, some of the stolen cars were later spotted by police and on one occasion by the (previous) legal owner doing rounds on the M25, but the police had no vehicle that can stop them at the time, until eventually some police forces got themselves Imprezas and Evos to catch joy riders in stolen cars.

[JamesV6CDX]

fuel - easy, you'll soon see if it's pressurised in the injector rail, by pressing the bleed valve in

Compression - test as per any engine

spark - I usually attach a strobe to each HT lead in turn, it won't tell you anything, other than if it's sparking or not though!

[Marks DTM Calib]

Multiple faults here I would say....

Start by checking the LPG install and associated fuses.....clearly a supply issue here and I think its also the cause of the problems on the Petrol side as the LPG ECU might well be being back driven off some of the shared sensors/actuators (I'm thinking injectors).......this would cause the dim light and teh possibility of sometimes getting it to run....

I ahev to be frank....the more i look into the LPG controllers.....the more I dont like them.......they seem way to bodgy for my liking...

[Taxi_Driver]

Still wouldnt start this morning....

Checked the fuel line as James suggested.....a little spirt then nothing.....is this normal?  :-/

Swapped the coil pack back over....still not starting.

Then tried the cheapo tech2 on it.....nothing....wouldnt read the ecu   altho it has done before

Now was getting worried ECU had popped its clogs......

What i missed last night.....was another fuse box in the engine compartment, buried underneath another fuse box with some relays/fuses in it.

No mention of this box of fairly important fuses in my book of lies for a Vectra.

But they are on the circuit diagrams.....FV6 (20amp) had blown in a fairly impressive way.....looks like it had been arcing so hence the intermittant running.

FV6 is the feed for the fuel pump + the petrol injectors + the ecu ......so no wonder it wouldnt start.
Possibly also feeds the lpg ecu + injectors (book of lies doesnt cover dual fuels)

ECU light is now on with ign.....and lpg light on switch flashes as it should with just ign on, no longer a dim glow.

Starts and runs fine again now.....well, as well can be expected of nearly 200k miles  

So thanks for the advice and suggestions guys  

It lives again  

[Auto Addict]

 

[Taxi_Driver]

I ahev to be frank....the more i look into the LPG controllers.....the more I dont like them.......they seem way to bodgy for my liking...

FF LPG ecu's? or aftermarket kits?

I would like to see the wiring diagrams of the two options to compare them.

On my Vectra dualfuels both LPG Ecu's look very similar to the engine ECU.....the LPG Ecu's have two big looms connecting to them, much like the engine ECU.....which means a lot more wires than my Omega LPG ECU has going to it.....so question is I would like to know what the extra wires are for?

[TheBoy]

Having been caught out by an Astra fuel pump relay, I do tend to check for fuel now....