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Cold Idle Issue, Ke30


Benne

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Hi,

 

Perhaps there are answers to this somewhere here, but i'm new to the site and have not followed it for long. This seems to be THE site though

when it comes to old corollas.

I bought a Ke30 a couple of months ago and i'v been learning about it since then. I'v just recently started to get into cars and how they work.

I'm learning something new almost every day.

 

So now to the problem:

I noticed this after i had purchased the car. When it was cold, it required multiple tries before i got it to idle.

But this only happens when the engine is cold. Like in the morning and such. The car does run well otherwise and i'v had no other issues with it.

 

I will try to explain this as good as i can:

When i start the car all the lights work as they should on the dash, i turn the igition on and the lights dim a bit as the engine cranks over and i can hear and feel it start.

This usually lasts for a split second before the engine dies instantly. (note that there is no ignition problems. The engine starts on first try). I wait a bit and try again and repeat this over...it helps if i wait a bit more between tries. For every try, the engine runs a bit longer and in the

end it can hold a rough idle after something like 8-15 tries. It helps alot to give it some gas though. It also helps to choke it too. When i'v been driving the car for a while, it will start with no problems

and hold idle just fine. I think this is because the engine needs to warm-up and something is not working properly when it's cold.

 

Here is a video where i show the first two tries and then cut to the try that got the idle working. I can post more videos if it would help:

 

So what i'v done myself is:

Changed oil and oilfilter.

Changed fuel filter.

Charged the battery.

Cleaned carburator with carbclean.

Changed spark plugs (the old ones looked alright. Normal wear).

Checked for vacuum leaks without finding any (could not really do this properly since i only have start-gas and i don't know all the spots to check)

The airfilter looked alright. It could be changed but i doubt that would make any difference.

 

After these changes it did run a bit better. Especially cleaning the carburator helped, but it was not enough.

Maybe it has something to do with the carburator, i'v not tuned it since i have no rpm meter. Maybe the fuel pump is at fault, but how do i know for sure? I'v thought that perhaps it could be the valve clearance beeing off and affecting the valves. Maybe the cold makes the valves leak pressure... i don't know. That's why i'm here.

 

(Note: it gets noticibly worse in cold climate. It dropped below freezing point here (Sweden) this week and it required more tries than before.

The previous owner changed various gaskets like the head gasket, but i don't think he did anything else.I doubt it has seen any major engine check-up in several years.

The engine is the original 3K and just about everything else is original.)

 

 

Thanks for any help! / Benjamin

Edited by Benne
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Hi Benjamin,

Welcome aboard. Couldn't access your youtube video as it was set as private.

 

Despite the fact that you've sprayed some carby cleaner, I would suggest, that the carby would be the first thing to look at. Remove it and carefully dissemble and clean all jets & passages. It is always a good idea with olde carbies, that have not seen a service in a long time, or been sitting unused, to soak them for 24 hours in a cleaning bath. Plenty of instructions on the net how to do that. Those rubber hoses connected to the carby are always a source of air leaks, as they get hard, brittle & crack. Inspect all very carefully, but better still, buy a meter of new hose, & replace each section one at a time.

 

If you can start the car, and keep your foot on the accelerator, so that it idles very fast for a few minutes, then idles normally when you take the foot off the accelerator, the problem will be easily solved, once you find the culprit. I presume the carby is the original Japanese Aisan ? Get hold of the manual on the net, & study how this carby works. They are fairly simple.

 

Let's know how you go.

 

Cheers Banjo

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Thanks for the replies. I will try to clean the carburator thoroughly. Will have some time at the end of the week.

Hi Sven i remember you from the thread about door handles! Yes the engine was barelly able to idle there. I can post a video with better sound directly on the engine when it runs as it should (warm) if you would like to. I'm not good at determining what sound is good and what is bad yet. There is a slight metal sound from the exhaust piping, there is no metal sound coming from the engine atleast.

 

I will update here when i'm done.

Edited by Benne
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So i cleaned out what i could. Because i lack a good set of tools i could not reach in to take the whole thing of the manifold so i disassembled it from the top. I cleaned everything out with carb cleaner, but there where some things i could not reach. The result? It starts up instantly with choke. Without choke it still struggles for maybe 3-5 tries before the idle stays, but it does not seem to die as quick as before. This is a big improvement and it feels like the engine even runs a bit better overall, but still not perfect. Maybe it's the cold. It's around the freezing point here. I will try this again when i have better tools. One thing i noted was that taking the airfilter off helped. Why is that?

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Now it is running like it should. The choke creates drag in the incoming air, hence a larger vacuum in the inlet maniold when running and that sucks more fuel through the jets. That richer mixture can afford to lose fuel as it condenses out on the cold metal walls and still leave enough to run the motor. It also raise the idle speed with the choke screw, which you can adjust usually.

 

When you push the choke in things all return to 'warm motor' settings', and I find I might need to pull the choke out again a little if I have to stop in the first minute or so of driving, but actually driving along is fine.

 

A dirty air filter richens the mixture, but it has to be very dirty to have than effect.

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  • 3 weeks later...

yeh these engines are notorious for idling a bit sad when cold. some pretty sharp turns the air has to make into the intake manifold make it a sad evern during cold starts.

The better you can get fuel atomizing from the idle port, the better the cold start idle will be.

some carbies have a system which looks at the coolant temp and mucks with the mixture to richen it up when cold.

some have the oposite, an air valve which lets in more air (leans the mixture) when hot. i imagine yours has the latter. Check that is propperly sealing when seated. Its known as the hot idle compensator.

If leaking (common) it can cause a vacuum leak undetectable outside the carbie.

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