VS V6 Rough Start, low revs, shutters whole car, goes away after 5-10 seconds

[tpole]

Hi all,

I have a VS series 2 statesman V6. its done just over 260,000 so kinda low for a 1997 car, when i go the car it ran fine and about after a week i had it converted to duel fuel. a bit after that i noticed that in the morning it would start very rough, very low revs, sounded dead, whole car would shake violently and it feels as if the engine is about to explode or fall out of the engine bay or make the car fall apart and if i did not give it any gas it would stall. if i give it some gas and push the revs over 2-2.5k it will norm go away and then run normal. i then figued out it would only happen when the engine was cold and had been sitting there for 6 or more hours. i had the fuel pump replaced as the pressure was low and had no luck the problem is still there. then i also found that it would happen when i opened my radiator cap, i would hear a glugging noise and then water would flow out of where the cap would be, after this happened the car would 100% play up and do it for a week or so then go away as long as i did not open the cap again i spoke to a mechanic at work and he told me it could be due to a air bubble in the cooling system. so as my radiator was full of rust i replaced that and my overflow had all the hoses tightened and then filled and bled the system. this stopped the problem for about a week but then it returned. the car has a little white smoke but im not sure if it to do with the issue of coz its just so cold in melbourne atm most car seem to blow white smoke but once the car heats up it goes away. also if the car is left on a sloped road engine on the low site boot on the higher side the starting will be alot worse and can take a fair bit to start it as it will keep stalling. can anybody help me as i have been told that it need to have the head gaskets done and maybe the heads aswell and im looking at around 2 grand to fix it. note i have not had a compresson test done or had it checked by the computer doing this in 2 days. thanks heaps

also thought to add. when the car is shuddering the dash lights go dim and light up dim and light up as the car shakes. Gas system has Flash Lube system fitted.

[immortality]

ok, for starters a few questions.

which fuel are you starting the car on?

does the engine use coolant?

seeing as the problems started after fitting the duel fuel. try running petrol only and see how it goes.

when you start it and it's shaking itself to death it sounds like it has dropped a couple of cylinders. when running LPG you need to ensure your ignition is up to scratch or you will get a miss. good quality leads are a minimum and some quality plugs would help too. i suggest some Bosch leads, they do some that are recommended for LPG.

you also need to fill and bleed the coolant system properly

if the engine is using coolant it is 99% likely that it is the intake manifold gaskets and not the head gaskets. common problem with high mileage Buick/ecotec V6 engines.

the lights dimming would suggest a voltage issue. have the alternator/battery tested also

[tpole]

Umm have tried starting the engine on both fuels, at the start i thought i was a fuel mixing issue, i.e. i thought when i turned the engine off at night it was leaving gas in the cylinders, then pumping more in when i started and that was the issue so i would run it on petrol for the last 5k home and start on pure petrol and the issue still happened after talking to the gas people they said it starting on petrol anyways and once the engine gets going it kicks over to gas. when the system was put on they replaced all the leads filters spark plugs etc as they were old and they said it was needed for the conversion and to keep the warranty. the system was bled by my mechanic so i hope he did it right but he showed me that he did it right as he has to use a funnel like object to get the water level higher than the engine and when he opened the bleed spot air came out then water and the water was full stream no spluttering suggesting there was water there. when i first had the problem i took it back to the gas place they also re tuned the gas system and re gaped the spark plugs. the car was loosing coolant before but i have not looked since the new radiator was installed. car is re tuned on gas every 3 months as to keep the warranty on it, the great part was it was a 3 year full engine warranty yet it does not cover head gaskets or the inlet manifold, for them to be covered i need something else to go I.E. blow a head. if it is the inlet is it easy to fix if i have a gergorys manual and if so does anyone have one for a VS? hope this info helps if you need more just ask, im trying to get a video of it doing it yet it wont seem to do it when a camera is on and pointed at it

[immortality]

ok, could be a fuel injector issue. when you run on LPG it can cause fouling in the injectors. replace the fuel filter and run some injector cleaner

[tpole]

i put a new fuel pump and filter in bout a month after the issue appeared as the pump pressure was low, and injector cleaner was the first thing i put in the car, i only ever run 98 octane fuel, and i use gas from supagas which use pure propane not the mix your normal companies use, its a lot cleaner and more powerful so ive done what i can to make sure i can take care of it. its really annoying as i give so many different symptoms that it could be half a dozen things but for me to get each of them checked and fixed it all costs money which isnt that easy to get when your at uni and work at the local safeway 2 days a week that you have free.

[Brett_jjj]

Have the spark plug gaps been set to 1.1 mm.The standard plug setting for the V6 is 1.5mm, but when converted to run on gas they recommend dropping the plug gap back to 1.1 mm.Maybe this might help.

[tpole]

kool ill take a look at that but i dont think thats it the gas place is the one that gapped them so i hope ezy gas in sunshine know what there doing :S