Rough Idle and Stalling at low revs

[MichaelDenholm]

Okay, apologies for the long post up front :)

Been reading through the posts and got some ideas from similar problems but I'd like to lay out my issues and see what you all think... the car issues anyway, I'll keep the personal issues to myself :)

I have a '92 GQ Patrol 4.2 Petrol Carby (TB42) and it was running well with the odd skip almost like it was not firing in one cylinder at random intervals. Didn't think much of that at the time, was planning to convert to electronic ignition sometime in the future anyway...

After a while it started taking a while to warm up and had a rough idle. Sometimes it would stall immediately after starting, so I'd give it a kick and it would start fine.

Now I have to give it a bit of a rev to start it or it wont start at all and if the revs drop below 800 it stalls.

While idling at 900 (i fiddled the idle control) it runs rough as hell and blows a bit of smoketill it warms up, can take up to 10 minutes to clear up on a cold day.

All this said, it runs great when I am driving, its only really when the revs drop down below 1000 that you see any symptoms. Also when I turn the the engine off it gives a sort of death rattle, and does not stop immediately

Looking in the air cleaner box, there seems to be a lot of black in there, and the metal "grille" thingy on top of the carby chamber is discoloured and the label looks like its actually burned.
While the air cleaner box was open i started it up and ran it for a bit, and then when I turned it off there was a mist emitted from the top of the carby.

[Silver]

mechanic neighbour runs his with the choke assembly completely removed, and is tickled pink that his runs better than our '89 TB42.

He suggested carby cleaner - a cheap one, blast it around the choke mechanism, into the float bowl - via the white plastic 'snorkel' at the front top of the carby, and in around the choke butterfly swivels, and see if that improves things. Follow the instruction on the tin.

I did this and then changed the spark plugs (and leads) immediately after - they were very black and furry with carbon, I assume just from running rich with petrol plus cleaner, and not from just running on petrol over time.

It does seem to run better. I've had a bit of a muck around with the setting for the butterfly - three screws in a circle on the firewall side of the carby - look at the manual for more info. Scratch a mark on the cylinder part of the mechanism so if worst comes to worst, you can set it back where you started :-)

I have a Petronix hall effect ignition which I got on line from a crowd in Melbourne, and wish I'd got the long rotor button at the same time. the pertronix was not hard to fit.

Don't know if that will solve your problems, but is a cheap first step.

[MichaelDenholm]

something like this Silver? http://cgi.ebay.com.au/ELECTRONIC-IGNITION-Pertronix-Nissan-Patrol-GQ-TB42-/300525118846

[YNOT]

Sounds like you need a good tune up.
The death rattle when you shut it down is probably the engine running backwards which can happen if the ignition timing is out.

Tony

[MichaelDenholm]

yes, unfortunately its been lent out a couple of times (its sort of a spare car in my family) and it always comes back worse off...
Anyone know a good Mechanic north of Melbourne?

[growler2058]

Sounds like you need a good tune up.
The death rattle when you shut it down is probably the engine running backwards which can happen if the ignition timing is out.

Tony

Played around a lot with ol holdens as a youngster and still do, that used to happen when the vaccum advance hose came off the dizzy effecting timing can this happen with a petrol troll Tony

[AB]

yes, unfortunately its been lent out a couple of times (its sort of a spare car in my family) and it always comes back worse off...
Anyone know a good Mechanic north of Melbourne?

There's a great bloke down at Bayswater I use but may be a bit far from you.

http://www.dlook.com.au/car-mechanical-and-engine-repairs/vic-melbourne-bayswater/hi--tech-dyno-tuning-679798

You would expect a half decent mechanic in Whittlesea / Mill Park area surely???

[Silver]

something like this Silver? http://cgi.ebay.com.au/ELECTRONIC-IGNITION-Pertronix-Nissan-Patrol-GQ-TB42-/300525118846

G'day, no, mine must be the lobe sensing one. Will have to search out what the issues are with it :-) Seems to be going OK

[YNOT]

Played around a lot with ol holdens as a youngster and still do, that used to happen when the vaccum advance hose came off the dizzy effecting timing can this happen with a petrol troll Tony

Only the carby models, EFI shuts down the injectors.

Tony