HELP whats causes this?

minifb · Post by **minifb** » Mon Jul 07, 2008 8:28 pm

Hi All.
Im running a 308 with straight gas.Every now and then you will go to start it and it winds over as if its got no spark and wont start BUT there is spark every where.(and its getting heaps of gas).
You will have a fully charged battery and it just wont start

. However as soon as you jump start or clutch start it it will start sraight away take the jumper leads of and try to start again it wont start untill you put the leads back on..

Then it wont do it for months on end..Its been to 3 different Mechanics and they cant find out whats wrong with it. Its had heaps of parts replaced to try to find out whats wrong..
This is driving me crazy

..any help would be great..
Cheers Mark

rosco · Post by **rosco** » Mon Jul 07, 2008 9:10 pm

Hi Mark,
I'm not going to be much help here, but I would probably go down the line of shutting everything else off and pull fuses - it sounds as if something is causing one component to get "back doored"..........I expect you've checked the solenoid connections and main feed into the car..........
Might just be the extra boost making a bad contact........

Sometimes things are much easier to find when they break...... altogether....

these go one day and not the next - are the fear of all of us.........

frats,
Rosco

ps - good luck - when (and not if) you find it - please post, you'll save someone else a lot of grief........ it will come up again...

karsten · Post by **karsten** » Tue Jul 08, 2008 8:47 am

i had a pontiac that did that in cold weather when i lived in canberra,, used to chuck a bucket of hot water on the thing that heats the gas up with the cars radiator water to help it warm the gas ,, was always freezing up even after a few hours sitting ,, the valves seem to bind from the cold gas or somthing,, some gas fitups work good and some are shit,,, i did have a rodeo ute on gas / petrol,,, and it ran far better on gas and i never touched it and sold with280000 on the clock ,, talk to your local taxi croud and see who does there stuff

Dr Terry · Post by **Dr Terry** » Tue Jul 08, 2008 2:24 pm

Hi Mark.

What type of ignition system are you using.

Dr Terry

Finny · Post by **Finny** » Tue Jul 08, 2008 2:37 pm

Have a 225 doing something similar.

Does it only happen when the engine has previously been started ? Warm motor ?
Or does it only happen when cold ?

Also is it running electronic ignition ?

minifb · Post by **minifb** » Tue Jul 08, 2008 3:13 pm

Dr Terry wrote:Hi Mark.

What type of ignition system are you using.

Dr Terry

Hi Terry, Just a points dizzy

Finny wrote:Have a 225 doing something similar.

Does it only happen when the engine has previously been started ? Warm motor ?
Or does it only happen when cold ?

Also is it running electronic ignition ?

Its not electronic just points..it happens all the time..hot cold inbetween
Cheers Mark

oldnek · Post by **oldnek** » Tue Jul 08, 2008 10:57 pm

Hey Mark,

Sounds like you have minimal spark under compression. You may have heaps there with the leads disconnected, or the king HT lead pulled from the coil.

LPG needs real good spark to fire,

I'm pretty sure all early model Holden's using points had a resister wire built into them from the ignition switch to coil, bypass this wire and run straight 12volts, and use a non resisted 12volt coil.
I personally think this is the reason your car fires when its jump started,
The extra kick of surplus voltage.........

A good start to your cure would be:
Good quality HT leads for LPG are a must, electronic ignition is the go, and if you can get one I would advise you to throw it on............ but points system will be suffice.
Replace the condenser and fit a high energy ignition coil. Set the point gap to 0.012" and run plugs a heat range lower and set them at 0.025" to 0.028" no larger in gap.

There was also some issue with the supply lead from the starter, not the actual start wire, but another one which was also attached to the terminal on the constant side of the solenoid, ( On the solenoid there were 2 blade terminals on opposite sides of each other) this wire supplied constant power to the ignition switch, so minimal; current draw was felt through the ignition system, whilst the starter was engaged. I'm not sure if there was a mod for it. But I used to wire in a relay on problem vehicles that were hard to start.

Are you running a start enrichment solenoid on you converter, maybe that has stopped working and you not getting a pre- prime of gas. Whilst cranking, this would also cover up the miss diagnosis, when jumpers are attached, with the added cranking speed being able to pull the mixer diaphragm down to let sufficient gas through to start.

The other area I would look is make sure the inlet manifold has a good seal all around the intake ports, if the manifold gasket is leaking, especially on the bottoms of the intake ports, the engine is not receiving gas flow, due to poor vacuum.

If all else fails come for a trip to the coast

Regards John

minifb · Post by **minifb** » Wed Jul 09, 2008 10:51 pm

Thanks Guys, The car is running perfect now...Would love to make a trip down the coast John..Cheers Mark

hammondo · Post by **hammondo** » Sun Jul 13, 2008 8:50 pm

I had a 308 on gas and I had to replace the spark plugs every 10,000k's or it would play up on starting, despite having a good looking spark. New plugs always fixed it even though the old ones always looked fine. (it was a HZ red 308 with points dizzy). The guy who installed the gas recommended Bosch plugs but I found NGK to last slightly longer.

Never worked out why though?????

minifb · Post by **minifb** » Sun Jul 13, 2008 8:59 pm

Hi Im buying a HEI dizzy this week ..will see how it goes(i changed the plugs not long ago) Cheers Mark