VP V8 on LPG/Petrol broke down!

[jimmyd17]

Hey guys,

my VP V8 on dual fuel broke down tonight. It won't start on gas or petrol. Straight after it broke down (was driving on lpg prior), it would struggle to start but eventually fired for a few seconds on LPG before stopping again. At that stage, petrol would not work at all with no sign of firing. It has spark so i'm pretty sure its not an ignition issue. The gas converter thing up near the firewall was covered in white gas condensation. I'm guessing some electrical thing to do with the gas system, like a fuse or something? - which might also be not turning the injectors on when its switched to petrol?

Just wondering if someone has had a similar problem with a dual fuel commodore, and where the fuses and stuff are to check, or if it could be something else. i really dont know.

any help would be greatly appreciated,
thanks!

James

[jimmyd17]

okay, an update. i got it going again after leaving it for a couple of hours. it wouldnt start on petrol, but i cranked it for a while on gas and it eventually fired, and then i was able to flick it to petrol after driving it and it kept running. so now its working on gas and petrol as normal. i dont know what caused the gas converter to get all white condensation or whatever on it though. i'm not convinced its all good again just yet, still feel like i need to figure out what happened so i dont get stranded again.

[Troy5L]

maybe because gas is GAY!!!!!!

nah seriously takeit to a mechanic if you want to find the problem, it will be less hasle picking your brain for a few days or even weeks

[centy]

check fuel pump fuse contacts.
silver bottle up behind the strut towers is ac mate.
gas valve will have heater hoses going to it to stop it icing up and freezing shut or open so if it was the gas valve you have seroius problems.

[Warranty Void]

OK, you are freezing the converter (Silver roundy thing that was covered in frost) probably because you are low on coolant. The gas won't burn as a liquid, it needs to convert to vapour first, so when the converter freezes theres too much unburnt gas in the manifold and it won't run. It's pretty much the same as being flooded. Petrol won't work either as there's no air to ignite. Most LPG systems will let you hold the switch in the middle which means no fuel or LPG and crank the engine over until it catches. This will happen surprisingly quickly and it will run until the fuel in the manifold is used up. Alternately you can pull the fuel pump relay under the bonnet and crank on petrol for the same effect.
Your converter is hooked up with the heater hoses so if its got no coolant you need to bleed the cooling system with the heater control set to hot. Hope this helps.

[jimmyd17]

thanks for that! that gives me some idea that something is a miss with the cooling system. the car started fine this morning. i checked the coolant level and put a tiny bit extra in it, but it only took probably 200ml or so. after driving for about 5 minutes on petrol (wasn't game to try gas again yet), the temp gauge skyrocketed almost up to max very quickly, so i turned the heater on (climate control set to 32) full blast and the temp settled back down almost as quickly and the needle was almost down to normal until i was stationary when it was slowly creeping up until i was moving again. i was thinking perhaps a thermostat problem, however it had a new thermostat only a few months ago, unless its a dud thermostat.

so it seems like a cooling system drama or some sort. just not sure exactly what yet.

[jimmyd17]

water pump maybe? i noticed a squeeking noise this morning coming from the front of the engine around the belts which is a new noise.

[Warranty Void]

Sounds like you have air in the cooling system for a start, get a workshop manual (Haynes, Gregory etc) and follow the instructions to bleed the system (with heater on).
Briefly:
Just get it bled properly first, idle on gas with heater on and rad cap off and keep squeezing top rad hose and topping up rad until no more air bubbles come out and coolant is just overflowing rad. Put rad cap back on, give hose a few more squeezes. After a total of 10 minutes make sure the overflow is topped up and the cap is on properly then shut down and let it cool down. As it cools the system will suck in any more coolant required from the overflow tank.
Then check the fan clutch, it should spin relatively easily with the engine cold (ie lots of slip) but be absolutely blowing a gale when the engine is hot. Be careful not to lose fingers in the fan. Make sure your fan shroud is sitting in place properly.
I'd go ahead and use the gas, as long as you know about the flooding you won't get stuck again.
It's possible your heater hoses or a radiator hose has collapsed internally, as long as your heater seems to be working normally you can just about rule out the heater hoses.

[jimmyd17]

thanks heaps for the help 'warranty void', i'll try bleeding air out of the cooling system and see how it is then.

[jimmyd17]

just an update... the car seemed have air in the cooling system i think, cos it took a couple of litres of coolant when i had it running. heater is warm but not hot, however its always been like that for the last two years i've had it. it seems to be okay since i've tried bleeding air out. it hasn't overheated but the temp gauge is sitting at nearly 1/3 instead of 1/4 like it used to. i haven't had a repeat of the gas freezing, so i'll see how it goes. the engine is coming out soon to do bottom end seals, etc.. so i'm hoping to diagnose any causes of problems first. i'll continue to post up if i find out what has caused the problem so it may help anyone else with similar issues.

[jimmyd17]

okay, another thought today... it seems to be taking about nearly half a litre of coolant after a 15 minute drive. i can't find any leaks. i'm thinking maybe i have a small head gasket leak between a cylinder and a water gallery. if i start the car with the radiator cap off and top up the coolant, it bubbles up every now and then. is this normal? i'm hoping to pull the engine out in the next couple of days to do bottom end seals, so i'm hoping to figure out what this issue is before i do that so i can resolve it.

thanks.

[Warranty Void]

Probably your radiator cap relief spring is too weak/old, get a new cap ($10 or so) then drop by your friendly mechanic and get him to check the coolant with the hydrocarbon sniffer, that will tell you if your head gasket is leaking at all.

[jimmyd17]

i recently put a new radiator cap on. sounds like thats the best option to ask a mechanic to try figure it out. what is a hydrocarbon sniffer and how does it work?

thanks again

[levymetal]

it just detects whether there is exhaust in the coolant or not. a poor mans version is just to cut the bottom off a coke bottle and jam it inside the radiator neck and put a bit of water in it. start up your car and if it continues to bubble for 5 minutes or so then you've probably done a head gasket. you could put your nose in it and sniff for exhaust too if you'd like, but if it's bubbling then something is wrong.

[jimmyd17]

cool thanks. i'll try the poor man's version haha

[Warranty Void]

A mechanic should only charge you $20 or so to use the sniffer, don't wanna be pulling heads off for no reason or cos you got an air leak into the cooling system causing bubbles.

[jimmyd17]

that is true. thanks. i will take it to a mechanic before i pull the engine out. i've got a compression tester too so i'll see what readings i get with that as well.

[Warranty Void]

Check for white crap in the oil by looking in the oil filler hole with a torch, white crap=oil + water = head gasket problem.