89 GQ Carby/Gas Issues!

[GQBIGRIG]

Hi all,

I'm new to the forum so g'day!

Just purchased a 1989 GQ Patrol on Duel fuel 4.2 carby AUTO for my first 4x4!
When taking it for a test drive it was faultless..
On the way home a different story.. I driving in LPG (as it has been mainly tuned for this) I got about 20 minutes into the drive.. which consisted of a few uphill/descents at 100ks/hr it completely lost power (lpg cut out) and I heard a loud bang/pop from the engine bay and the lpg cut out.. I switched over to petrol and drove it to the petrol station thinking it was out of LPG.. filled it up with petrol/lpg and ran it home on petrol (with a few stalls).

Now the main issue is with LPG it runs fine cool, as soon as it must get to a certain temperature it obviously cuts out/ back fires in engine bay.. The converter is hot? not freezing up..

When running on petrol, runs suprisingly well.. until again when it warms up.. had driven 45km 100ks/hr get into suburbs get to a round about or after a long decent down hill it stalls.. then will not start.. I sit there about 5 minutes still no luck, then Im able to start it in lpg and then switch over to petrol no worries?

Confusing as! I just want it to be reliable enough to get me down to the west coast for fishing!

It has a new dizzy, leads about to change spark plugs, will be dropping the oil/filter within the week.. The gas system is OLD and really ideally I think it needs to be updated! (needs a new lpg tank)

I'm a little mechanical minded.. know how to use a spanner and service a car! Just need some direction and fellow advice and guidance from you guru's!

[GQ TANK]

LPG - Check the coolant level, could also be related to the thermostat closing - had this problem on my rb30 was due to faulty thermostate

Also try turn the heater on when the lpg plays up - could be due to a missing or blocked heater bypass hose.

Also tray spraying some carby cleaner down the carbys as the carbys gum up if run only on LPG - I had to put a kit thought my tb42

[threedogs]

If your gas back fires and wants to blow the air cleaner box off you are running too lean on gas,
on the converter there will be a screw with a spring on it back that out 1/2 a turn no more.
Also make sure all the hoses are tight and not leaking air. Park your new Patrol on a hill nose up and invert a coke bottle with the butt cut off into
the radiator, remove as much air as you can especially the highest hose on the converter,
. Also to make your gas system more efficient replace your "TEE" pcs with "Y" pcs . This will stop cavitation and allow a smooth flow of your water, Timing will need to be advanced a touch as well.
You wont be able to tune both to achieve 100% performance.

[GQBIGRIG]

Thanks for the ideas boys I will have a go this w.e see what I can rectify

[NP99]

Why replace the tank? Have it checked and re certified might be a cheaper option!

[threedogs]

If you do replace the tank, find the bigger 120lt job
extend your range,, about 105 lt to fill

[GQ TANK]

The only problem with running the 120l tank is how low it hangs, im for ever hitting my tank off road. - gives 90L usable.

Have a look at your tank, if it has any surface rust - it wont pass inspection- I have a few retested by a guy in Melbourne. He has knocked back a couple with surface rust.


Have a look at this site for tunning you LPG http://www.diy-lpg.co.uk/articles/files/tuning-open-loop.html

[threedogs]

Must be different on the Patrols never hit the tank in my troopy ever
I was able to get 100 usable that why I changed it

[GQBIGRIG]

I spoke to Colin Schubert at Modbury a recommended 4x4 mechanic, and he believes it sounds like valve clearances. We spoke and came to the conclusion it is probably best to remove the LPG system. The reason I would replace the tank is yes, it has surface rust and is 14 years old. At the price of LPG anyway 95c/ltr is it worth having LPG?

[GQ TANK]

If you have the standard tank - then you can convert it back

[GQBIGRIG]

Okay, spent some time today, changed the spark plugs.. Yeah they where defiantly due to be changed.. nice thick sandy like film corrosion. Sand like color.

Did the first two cylinders 1: 135, 2: 130 PSI

- Will be doing valve clearances next week - I feel this will improve the overall compression.

Have spent some time with earth points, cleaning, sanding away debris and relocating wiring. I have run some pliers over every electrical connection to ensure it has binded to the wire.

More to go tomorrow.. Will get some coolant and flush/fill with some good antifreeze for the LPG, then need to drop the oil!

I feel alot better about the car already doing these minor things.. it has needed some TLC!

[BigRAWesty]

Gas is 105c/L down here. Really not worth it.
But good to see your finding the issues.

[GQBIGRIG]

Well, I have flushed the radiator and put in some decent anti freeze / boil coolant, appears the temp gauge has started to actually work! Since going over every peice of wire connection with pliers and spending time on the earthing points.. my LPG problem no longer exists! I took it for a long drive yesterday all around town and up the freeway, I even took certain exits thinking to myself if its going to happen, itll happen here haha.. Well it didn't.. nice warm day, got to 1/2 way on the temp gauge up the freeway (up the hills). So I'm very happy about that..

Going to to the valve clearances this weekend with the uncle.. should make it run even better!

[93patrol]

Good job mate. Goes to show a little TLC goes a long way