My TP sedan (carby model) has had an intermittent surging problem recently. Runs ok at idle but stalls or bucks and splutters when load is applied. Strangely enough goes fine at full throttle. Sometimes it clears itself and runs well all day.

It happened again Monday just as I was parking it - suddenly spluttered and then died. I can't restart it. I had already replaced the fuel filter as that was my first guess. I'm getting spark but no fuel. I poured a small amount of fuel direct into the carby and that works - it fires immediately and runs for a few seconds.

The fuel pump relay shows voltage when I crank it so I think it must be the fuel pump itself or a blocked fuel line. The trouble is I can't get at the fuel pump to check it. It is parked on sloping ground on loose gravel and near a post so I can't jack it up. Today i will try to make a gravity feed setup with a small bottle of fuel so that I can start and move it to flat ground.

Do you think that will work and how much does a new pump cost? There are a few sellers on eBay with new EFI fuel pumps for about $135 but none for the carby model except mechanical pumps for the TM.

well the pump pressure is about 3 psi you might find

repco carry the pumps dont know

you could use a pump from a wrecker if you have to

it also may be the small fuel pump diaphram on the carby itself

you can test the pump by undoing the filter
and with a helper see if it pumps fuel when turning over

Thanks for the quick reply, Magna Buff. Unfortunately I don't have a helper or anyone nearby to ask but I've made some small progress. I tried the gravity feed arrangement by disconnecting the output line from the fuel filter and connecting a 1 litre bottle of fuel to that line instead. I put a hose on the fuel filter outlet and ran that into a jug. Although the fuel bottle was properly vented, the gravity feed didn't work. The engine would only run for a few seconds if I put some fuel directly into the carby.

It did prove that the fuel pump was working because it pumped some fuel out into the jug. So I can probably forget the fuel pump! Then I checked the hoses between the fuel filter and the carby and I can blow through them all except the one to the accelerator pump. That would make sense unless its diaphragm was broken. Is that the pump you were referring to?

According to the manual, if you look down the carby barrel and manually open and close the throttle, you should see the accelerator pump send a stream of fuel. It doesn't. The carby's as dry as a bone. That would account for my earlier symptoms but I'm surprised it would stop the engine running completely. So I think there is another problem as well as or instead of that. For some reason, fuel doesn't seem to be getting to the carby at all even though the fuel lines are clear.

http://i253.photobucket.com/albums/hh59/magnabuff/carby_side_2_153.jpg

that little pump there is a diaphram
you can buy a carby kit from repco

or the jets inside the carby are blocked
dont loose the float needle
take the top off and blow compressed air throught the jets

Thanks, Magna Buff. I think you are right. It must be either the jets blocked or the accelerator pump diaphragm broken or both. I will have to take the carb. apart but I don't have any gaskets and I'm 75km from the nearest Repco. The wagon's off the road too. I'm trying to replace the rear engine mount on it. I have the old mount completely undone but can't get it out, let alone get the new one in. I'm going to undo the driver side mount as well so that I can lift the engine a bit more but I need to lift it about 10cm. There seems to be only 2 to 3cm of movement possible before the gearbox will hit the body, so it doesn't look good at this stage. I will let you know the result.

Had to give up on the wagon. There was no way I could manouevre the mount out through the gap, so I just bolted the old mount back in. It seemed to reduce the vibration quite a bit so may not have been tight enough before.

I've taken the carby off the sedan and have it apart (see above re charcoal canister).
The bowl is like a sewer - full of a sludge of charcoal and petrol. The good thing is that now I know exactly what the problem is. The bad part is that after I've cleaned it I won't be sure that I've got the charcoal out of every nook and cranny.

Give it a good squirt of methylated spirits or petrol to try and clean it out. Remove all of the charcoal from the cannister, or disconnect it from the carb and plug up any hoses. You probably have ground up charcoal in the engine so check your oil.

Thanks for your help. I cleaned and re-assembled the carby this morning. Didn't even lose anything.:happy:

Connected it all back up and the car started first time. Runs beautifully with no more surging, just smooth instant response.

And yes, I took particular care that charcoal will never again get anywhere near the carby.

lol This is the first time I've heard of a charcoal cannister spewing up into the carb! Good you found and rectified the problem!

This charcoal thing is new to me. The motor only draws vapour from the canister. It is a very small hose that takes the vapour from the canister to the air filter housing. Dont know how it could end up in the float bowl.
Havnt recently changed to E10 by any chance. E10 can loosen a lot of crud from the tank and lines, but it should get caught in the filter.

This charcoal thing is new to me. The motor only draws vapour from the canister. It is a very small hose that takes the vapour from the canister to the air filter housing. Dont know how it could end up in the float bowl.
Havnt recently changed to E10 by any chance. E10 can loosen a lot of crud from the tank and lines, but it should get caught in the filter.

It is a mystery to me how the canister's construction can allow charcoal to get out.
However I've just found a description in the factory service manual for 2nd gen carby. engines of how the system is supposed to work.

The pipe I was referring to is about 10mm inside diameter. One end is conected to the canister and the other to the carburettor bowl vent valve. Apparently, it is supposed to allow excess fuel vapour from the carby to be stored in the canister. However in my case the flow was in the other direction and it was sucking the charcoal granules from the canister into the carby.

The manual mentions a filter built into the bottom of the canister. I have to assume the filter has collapsed and allowed the charcoal to escape.

I thought the problem was fixed but not so. I'm still having intermittent surging even after cleaning the carby. I am still working on the answer but I think the carby vent valve may be faulty.

I have similar problem to this my Mitsi TP car was hard to start in hot weather. I pulled the carby off and cleaned it out now it doesn't run at all so I suspected the fuel pump too. There doesn't seem to be much flow of fuel and it is intermittent. I noticed what I thought was bits of black plastic like granules in the carb and cleaned them out but other than that the carby was quite clean except for a bit of sediment in the bowl for a 20 year old car.
My car only runs briefly now unless I pour petrol in the carb and it always started well before except when hot so I wonder if I need to clean the carb again as I don't have compressed air. Some of the gaskets fell apart but I thought the car would still run at least
until I can get a gasket set. Auto barn seem to be the cheapest at $79. Does anybody have any thoughts what could be wrong?

the fuel pump only runs low pressure
and is inside the tank
TM TN TP later Carby electric 12 v in tank delivery pressure 19.6- 25.5 kPa = 3 psi

to replace it you need to find a carby car at the wreckers

they do have fuel pumps on ebay for the magna
you will have to make sure they suit the carby

thats a good price for a carby gasket kit

some kits only have one needle and seat for the float which is non adjustable
the TP needle is different on some models

you have to check the dash pots hold vacuume

and all the vacume lines are sealing