Vacuum leak test results on GQ RB30 Patrol

[dom14]

Vehicle is stilll running pretty ok. I still hear occasional hesitation or misfire, but nothing like before.
There's considerable power increase on LPG.
Only "fix" I did for it was to play with(unplug and plug) the distributor vacuum advance line and blocking the two vacuum lines that
goes to the charcoal canister.
So, guys, what did I do?!
Did I fix it or did I patch?
Any kind of speculative feedback would be great.
Over the internet, via paper mail or a scream in front of my joint.

[garett]

if you reconnect the 2 lines to the charcoal canister? does it go back to what it was ? a mighty vac could help you check the vacuum diaphragms, should be a way to check canister and vac advance in the workshop manual, may be just a leaky connection ?

[dom14]

if you reconnect the 2 lines to the charcoal canister? does it go back to what it was ? a mighty vac could help you check the vacuum diaphragms, should be a way to check canister and vac advance in the workshop manual, may be just a leaky connection ?

Hi Garett,
Of course mate. That's a logical way to test "my theory"(faulty canister).
I've got carried away with trying to locate electrical issues, I forgot about it.
I found two electrical issues which I'm about to post on a separate thread in the electrical section.
Before that, I'll go and plug the charcoal canister vacuum lines the way they were and see how it goes.
I didn't understand what you meant by "mighty vac"!
I'll see if there are any tips on how to test canister & vac advance in the manual.
I'm pretty sure no leaks from outside. From the smoke test & WD40 test(can't say 100% sure though, there
might be something I've missed).
I'll go and plug the canister vac lines and see how it goes.
Thanks

[dom14]

I did the following tests in below order.
I started the test on LPG.
Charcoal canister vacuum lines were disconnected and blocked.
I started and it revs and drives ok. Revs can go above 4000rpm without any hiccups.
While engine is still running, I plugged the charcoal canister vacuum lines back into the canister.
Then I tried driving. I couldn't rev above 3000rpm. When I tried engine stalled.
So, I thought it must be the charcoal canister causing the issues.
So, while the engine is still running, I blocked the charcoal canister vacuum lines and test drove again.
Still I couldn't rev about 3000rpm, and worse it even started stalling even in 2000 rpm.
All these rev tests were done while trying to take off on gear.
Then, I did the high revving while the vehicle is on neutral gear.
Now, it revs above 4000rpm without issues.

So, on LPG, the stalling happens whether the charcoal canister vacuum lines are blocked or connected.
Stalling doesn't happen when the engine is revved high on neutral

Then I switched the fuel to petrol and drove the vehicle while trying to rev high.
Now, it revs on petrol above 4000rpm without any issues on petrol.

So, on petrol, it seems to be going fine.

Weird behaviour!!!
What do I make out of this?
After above playing with vacuum lines, it's not running properly on LPG now, whether charcoal canister vacuum lines are blocked or connected.

NOTICE!
Hey guys, please pardon me. Above test results were wrong.
It all caused by a combination of a faulty LPG gauge & my stupid assumption(s).
Explanation is on the next post

[dom14]

Hey guys,
My sincere apologies for wasting brain time with the above test.
Special apology to Garett for wasting your brain time with the above stuffed up 'test'.
I'm a stupid idiot!
The weird behaviour was caused by running out of LPG(sounds pathetic I know).
I couldn't high rev on LPG 'cos the main tank was running out of LPG(damn gauge was showing one green bar though)

1)I have two LPG tanks. Only the main tank has a gauge connected to the dashboard.
And that gauge turned ought to be faulty. It shows one green bar, even when the tank it empty.

2)I shut off the auxiliary LPG tank from the tank tap. I was under the stupid assumption
that closing the tap won't fill the tank. Two tanks are connected via a hydro T-valve.
Shutting the tank tap only stops the LPG coming out of the tank, then going to hydro valve and then going to the
inlet from there. But, that won't stop from the tank from getting filled.(Correct me if I'm wrong).
Both tanks are sharing the same filling point(no separate fillers).
When I checked the auxiliary tank, it has a full tank of gas from getting filled over the time.
I shut the tank a while ago 'cos it was making funny noises, but stupidly thought it
would shut the LPG outlet as well.

Lately, I've been getting about 4km per litre of LPG instead of 5km per litre.
I thought that 'cos of my high revving and performance issues with the fuel system.
But the obvious reason was some of the gas was filling up the aux tank via the hydro
valve and getting trapped in there, thanks to my stupid assumption.
Obviously I need a separate tap for the aux tank fill line, if I'm to isolate it completely.

Please don't get me wrong, even though I made the above stupid mistake, I was still having issues with the fuel system,
and it's most likely whatever was causing it is still there, including the potential electrical issues with the fuel system.


So, here is the latest accurate outcome.

1)Whether the charcoal canister vaccum lines are blocked or connected, it is not making any difference to the
the way engine is running. So, It's apparent the charcoal canister or the two vacuum lines connected to it
have nothing to do with the issues I've been having before.
2) Above is the same for both LPG and petrol.

Obviously for my needs, I either need a separate filler for the aux tank or a separate shut off valve/tap for the aux tank fill line,
as well as a separate dashboard gauge for the aux tank.
I also need to get the main tank dashboard gauge replaced. It could be either the gauge or the sender.
I couldn't check the main tank sender, 'cos it's under the chassis(It's a PITA job).

[dom14]

This is my setup with AMR T-valve, exactly as in the diagram.

http://www.amrgas.com/hydrostatic-te...es#prettyPhoto[123]/0/

[dom14]

The vehicle is going fairly well on LPG atm.
Occasional hiccup here and there, occasional hesitation here and there, but all around
far better than before.
Funny thing is that I have no idea how I fixed it, or whether I fixed it at all.
Any thoughts guys?!

[dom14]

[garett]

that could be a mixer issue a converter issue or maybe a tuning one ... depends on when exactly it happens, easiest is prob check how clean mixer is, followed by converter, if i remember right should just be cleaning of the rear section.

but drive it for a bit and see if it comes back.

[dom14]

that could be a mixer issue a converter issue or maybe a tuning one ... depends on when exactly it happens, easiest is prob check how clean mixer is, followed by converter, if i remember right should just be cleaning of the rear section.

but drive it for a bit and see if it comes back.

Hey Garett,
Thanks mate. I'm driving the fourby everyday now. On LPG, it has a slight misfire when cold, then goes away after 10-15 minutes or so.
But, I reckon, whatever the issue was, it must be still there. I must have patched it up with my vacuum line fiddling.
I'll see how it goes. Still can't find the damn vacuum tester.
Cheers.
Dom
P.S. I'm gonna put the rebuild kit through the original LPG converter and fit it in soon. So, that should help as well.
I will get to the LPG mixer dismantling as well, once I've done some reading to understand how it works, I should
be able to know what I'm doing.