Idle issues

[Nath wade]

Hi I have a 1984 Pajero with a 2.6ltr 4G54 motor. The car has been sitting around for a over 12 months and it had 1/4 of a tank of fuel in it. I recently replaced leads, plugs dizzy cap and rotor button. I also put fuel doctor in it and put 98 octane fuel in it. Ever since it has recently just started to idle pretty rough and whilst driving it, it has started to hop a bit in gear! Like it’s starved of fuel “maybe”. First question is, Just wondering has the fuel doctor loosened up a heap of crap and blocking fuel line and should I just replace the fuel filter! Second question is, and should I be using an additive in the fuel being an older motor??

Cheers Nath.

[geopaj]

Do these have points or electronic ignition? If points, they need changing too.

I’d change the fuel filter (cheap & easy) and check the ignition timing, dwell, and carb mixture - assuming you’re familiar with how to do it (otherwise you could risk making the tune worse).

Maybe buy or borrow from the library a Gregory’s workshop manual and work through the basic tune up set?

[Nath wade]

Cheers mate, yeah it has points! Which I’ve changed! But thanks mate I’ll suss it out!

[chippy4x4]

Cheers mate, yeah it has points! Which I’ve changed! But thanks mate I’ll suss it out!

Being a carby motor that has sat around for an extended period you may have crap in the fuel bowl. The old bush trick is to find a can, like a baked bean can, that fits over the carby throat where the airfilter sits. Get the engine up to operating temp. Then rev the engine high, 3000 to 3500 revs, have the can ready and use it to block the throat off. What this does is turns the engine into a vacuum pump. When the engine stalls, having been flooded, have a look inside the can and there should be crap in the can, repeat as many times as you need. The blocking of the air intake means that the vacuum will drag fuel upwards through through the bowel and out of the ventury tubes and then down into the motor, thus "vacuuming" the fuel bowel. Also have a look at the high tension lead and connections between the coil and distributor cap, could be corroded. Old coils had a habbit of getting hairline cracks where the lead plugs in. If you like you can clean the area with some steel wool and and then raid you ladies nail polish and give the plastic a coat, this, when dry, will reseal the area against arcing . (of course be wise about the colour chosen, your mates WILL see it at some stage, so make sure the nail polish is your colour. LOL. sorry old fart humour

[old Jack]

Chances are you may have water in the fuel tank so best to drain and flush the tank along with all the fuel filters. Carby bowl could also have a water and dirt inside so take the top off and have a look. Older petrol engines were designed to run on leaded fuel so I would be using 98 Octane and fuel additive.

OJ.

[mudraiderus]

Should be a drain in the bottom of that tank. Probly late now that you've been driving it, but should of just drained it from the get go. Live and learn.

Sent from my SM-G950U using Tapatalk

[chippy4x4]

If you think that you might have water in the tank, pour a cup of methylated spirits into the tank. This will mix with the water and break it down so that it will slowly pass through the carby to be burnt off. Got to love these old bush tricks...lol

[Nath wade]

Thanks for the input and advice! I’ll be sure to look into the can trick as well as drain the tank! Thanks again for everyone’s help! I’ll be sure to post the results!

Cheers Nath!

[Ratbago]

These heads were designed to run on unleaded fuel , the valves are fine with unleaded fuel . A higher octane fuel is a good idea however . If its the stock carby its very temperamental , especially as the secondary is vacuum actuated. Take your air cleaner off and make sure your choke plate is opening fully.

[chippy4x4]

These heads were designed to run on unleaded fuel , the valves are fine with unleaded fuel . A higher octane fuel is a good idea however . If its the stock carby its very temperamental , especially as the secondary is vacuum actuated. Take your air cleaner off and make sure your choke plate is opening fully.

From memory the chokes on these were actuated with a spring operated actuator, that when the coolant heated up the spring would "grow" and turn the choke butterfly shaft. It was not uncommon for them to sieze up. If this is so they can be converted to a manual choke if you want to.

[Ratbago]

From memory the chokes on these were actuated with a spring operated actuator, that when the coolant heated up the spring would "grow" and turn the choke butterfly shaft. It was not uncommon for them to sieze up. If this is so they can be converted to a manual choke if you want to.

Yep forgot to mention that , the choke is activated via a wax pellet , the car heats up the pellet expands and pushes a diaphragm which is connected to the choke plate . These are notorious for not working properly . Mine didn't work when i bought my rig , blew black smoke from how rich it was running . As a temporary fix i made up my own choke plate that was half the size in area of the original . You can buy replacement wax pellet setups but its generally advised that you either convert it to a manual choke or replace the whole carb with a Weber 34.

[chippy4x4]

Yep forgot to mention that , the choke is activated via a wax pellet , the car heats up the pellet expands and pushes a diaphragm which is connected to the choke plate . These are notorious for not working properly . Mine didn't work when i bought my rig , blew black smoke from how rich it was running . As a temporary fix i made up my own choke plate that was half the size in area of the original . You can buy replacement wax pellet setups but its generally advised that you either convert it to a manual choke or replace the whole carb with a Weber 34.

That's it wax pellet. I had a 50% chance of being correct. LOL. Been a long time since I have worked on one. Cheers