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5K Rough Operation

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Another issue joins the list and a couple of days ago my 5K started idling rough, like it has a power shortage, sometimes it stalls. After this I took it for a spin and it happens while cruising too, it's a very strong cut, you can feel the car jump...

Spark plugs and cables look OK, rotor and cap are a bit worn out. Dizzy points and condenser are 4 months old.

Any clue?

Could the dizzy delay the engine timing?

Vacuum leak around the manifold or carby.

Do you still have the oil pressure problem? Is this the next sign of a 5K on the way out?

 

Does it smoke under acceleration or burn oil? I'm wondering if the tac tac tac noise was a broken ring and now that cylinder is fouling the plug. Pull the plugs out and see if they are all the same colour.

 

When its idling poorly you could pull plug leads off one by one and se if you can find the weak cylinder. If they are all equal it must be something general like gav says, an air leak somewhere, dirt in the carb... Its likely something that has been disturbed while you were working on the motor doing something else, but these intermittant problems can be hard to find. I've seen a wire broken so it just rests on the coil, then comes off, then goes back on.. a leaf in a fuel tank that covers the outlet, then as soon as the motor stops it floats off until it gets sucked on again..

 

If the weights dry out and jam the dizzy will not advance. That can be checked by taking the cap off and seeing if the rotor & shaft can be turned a few degrees by twisting it.back & forth. You can inspect them by just popping the base plate out of the dizzy.

  • Author

Yes, still having those oil pressure issues.

I'm gonna rebuild the engine soon myself as no one seems to be able to handle this simple engine...

But this cut problem suddently appeared and I want it solved before rebuilding, counting it's not related with the oil pressurei issues, of course...

Cut out or missing under part throttle is usually associated with lean or short fuel supply. This can be a direct fuel supply issue in relation to a faulty pump, blocked filter or some such. This fuel starvation is usually more prevalent under full engine load or heavy throttle.

 

Or as before a vac leak will cause fuel ratios to lean out as air gets it where it shouldn't. And vac leaks are most prevalent under idle and part throttle when the manifold vacuum is greatest.

 

  • Author

Can anyone tell me what vacuum hoses I can eliminate? I have all the carb setup from a MK3 Starlet KP61 (4K engine) and it comes with a complex system of vacuum hoses that I heard can be reduced to just the essential!

I could never get my 5k to run right with a 4K carb. Not enough air or fuel at idle. So I went with a DGV Webber.

  • Author

I have a DGAV 32/36 Weber to go in, but in the meantime I want to make a few tests

I could never get my 5k to run right with a 4K carb. Not enough air or fuel at idle. So I went with a DGV Webber.

 

Same here. Used to rock the whole car at idle - people used to think it had a huge cam in it :) Idled a whole heap better when I went to the 3kb set up.

  • Author

Did a spin today and managed to get some feedback of this problem.

It happens when the road goes up! If the car it's cutting and I the road starts to go down it stops and works fine. So it seems to be some fuel issue. Something gets out of fuel when the front is higher than the rear..

  • Author

Replaced the pump, it seems like it solved my problem. Haven't driven it in the street yet, just a few minutes working and revving in my place.

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