GQ 89 distributor

[GQPatrol147]

Hi all,

I've had a hard time of late trying to diagnose a stalling/backfiring issue on my crane electronic ignition dual fuel patrol. I changed a few

things like plugs,leads,dissy cap, some wires, ignition switch, lpg safety switch, fuel filter, vac hoses etc. It was a shit of a thing trying to

diagnose myself but the problem finally worsened a couple of days ago and it would hardly idle without pumping the gas pedal. Well

checking things again I found it idled smooth and run OK if I disconnected the vac advance. It might be time to throw another distributor

on it and my question is what should I be paying for a second hand one? Cheers!

[dom14]

Important thing to notice is that your Patrol is dual fuel.

Do you have this problem in both fuels?!!!!

If it's LPG only problem, then concentrate on LPG system(following what you've done already).
This includes the LPG converter, all the electrical connections related to LPG.
Pay special attention to any earth connections related to LPG wiring.

What I would suggest is that if you still have with you the old point ignition system, then install it and see how it goes.
That way you can confirm whether the after market electronic ignition system works ok or not.
I'm not familiar with the Crane electronic ignition system, but I've seen the Pertronix system.

Having a second dizzy is a very good idea with both TB42 & RB30 Patrols.

I carry with myself a second dizzy, ignition coil, leads, spark plugs, etc etc to deal with these kind of issues.

Where did you disconnect the vacuum advance to get the idling going again?
From the dizzy or the TVV(thermal vacuum valve)?

Idling going good after disconnecting vaccum advance indicates a timing issue.
Was this when the engine is cold or warm?

[GQPatrol147]

Hi dom14, it's playing up on both petrol and gas. I've changed a few wires and cleaned a lot of terminals. I only got it middle of last year and took it from Sydney to Tamworth and back and it was faultless until this all started. I disconnected the vac advance hose at the carby and plugged it that's why I'm pretty sure the fault lies within the dissy, maybe the springs/weights. The advance moves with a suck on the hose and seems to hold vacuum OK but that's only using a tongue as I don't have a guage... I'll check the timing again but it was OK last time I checked it. Thanks for the reply, cheers!

[dom14]

Where about are you located?

Have you tested to see if the spark is strong enough?

weak spark can also cause problems.

I would also suggest to have a good look at any possible carby issues.
This Nikki carby tend to develop problems after years on dual fuel, both in TB42 and RB30 engines.

One popular problem is the throttle body coming loose from the float chamber.
Throttle body is attached to the float chamber with three bolts that goes in from the bottom end of the throttle body.
When they come loose, all sort of weird problems manifest itself.
Remove the air cleaner and feel to see whether there is any subtle movements of the carby.
If so, remove the carby and and tighten the three bolts from the bottom of the carby.
Apply a thin layer of grease to both sides of the gasket, whether you're using a new carby base gasket or the old one.
I use white lithium grease, which is the best thing to improve the seal.

Is the idling problem the same whether the engine is cold or warm?

[GQPatrol147]

I'm in Sydney, I checked for any play in the carby and it felt OK. It was happening any time hot or cold but it gradually failed at start up by firing up but running with a huge miss until the vac adv is removed and it runs and drives normal. I changed the coil, leads, plugs, cap and all voltage is good.Cheers

[dom14]

I'm in Sydney, I checked for any play in the carby and it felt OK. It was happening any time hot or cold but it gradually failed at start up by firing up but running with a huge miss until the vac adv is removed and it runs and drives normal. I changed the coil, leads, plugs, cap and all voltage is good.Cheers

Ok, cool. I would look into the dizzy then.
If that doesn't work, then my money's on the carby.
Cheers.

P.S. I was going to suggest fuel filter and fuel pressure check as well. But, since the problem is there on both fuels, it can't be a petrol fuel
pressure/blockage issue.

[GQPatrol147]

Yes mate, I ruled the petrol pump out early because the problem was on both fuels but I still changed the filter as it's only a $13 part. Just after a dizzy and maybe I'll try a Pertronix next but I can honestly say the Crane one that's in it now has been going well. I'm pretty sure it's just something a bit worn or sticking in the dissy itself. Cheers dom14

[dom14]

Yeah, that might be true. Even with the electronic ignition in it, the dizzy is still a mechanical thing.
They do need rebuilding after so many years of use.
The vacuum advance mechanism(the springs, lever, etc) do wear out or get clogged up with crud after a long time.
Mine is an RB30. The dizzy comes with a stock electronic ignition system.
I recently opened it up and did a careful cleaning of the inside.
I also bought a spare dizzy which I keep in the car all the time.
RB30 stock dizzy electronic ignition unit is pretty good. It doesn't fail that often.

[NissanGQ4.2]

I'm in Sydney.

Where in Sydney? I have a GQ sitting here you can use parts off 2 eliminate issues. It's EFI though not carby

[GQPatrol147]

Where in Sydney? I have a GQ sitting here you can use parts off 2 eliminate issues. It's EFI though not carby

Thanks for the offer mate but mines a carby model. BTW I"m in Smithfield, cheers.

[laval]

Springs in the overspeed rotor could be corroded...

[mudnut]

The vacuum advance diaphragm can split which causes a vacuum leak as well as changing the way it works. I got a reco one from Bursons. They had to send it away to get fixed. If you can get hold of a vac pump, connect it and see if the unit holds negative pressure. Just use the pump gently.

[GQPatrol147]

Could be, I've been off line for a while... cheers