Hi All, Just bought this s/h Corolla. Gen 117,000 kms. Has a sweet engine does not burn oil. Just changed air and petrol filter. All plugs cleaned, gapped and spark well. It starts right up but when it gets a little warm runs rough and then dies. The car has had very little servicing and the petrol and air filter was caked. Any ideas what it could be! Maybe dirt in the carb! Choke sticking on! It is the 16V motor, auto, just before fuel injection. Ta.
mechnificent,
Jan 21, 9:31pm
Have you tried tweaking the mixture screw a little!
glyn4,
Jan 21, 9:47pm
No I'm not sure where that is on those carb's. I've tried adjusting the tick over using the wheel at the rear of the carb but it doesn't stop it stalling. The plugs actually looked quite good colour wise when I took them out.I think I'm going to take the carb off and clean it out today but it has 100 vacumn hoses connected to it. Is it a straightforward job if you take it slowly! Anything to look out for! Cheers.
unbeatabull,
Jan 21, 9:53pm
What engine is it! If its a 16v I woulda guessed it would be a 4A-GE but as far as Im aware they didnt come out factory with Carbs
Nevermind, forgot the 4A-F was also a 16v.
mechnificent,
Jan 21, 9:58pm
Is this one of the laying down slide type carbies!
If so there is an adjustment screw at the back near the firewall. if my memory is correct.
I'd doubt that there would be anything to clean in the carby. Wear perhaps might be an issue but I'd doubt there would be dirt.
mechnificent,
Jan 21, 10:02pm
It's also likely to have a hot air adjustment valve inside the air-cleaner. it is a bimetal strip that opens a bleed valve that lets extra air in when the car has sat stopped and is suffering from what they used to call heat soak(in the olden days). You could check that or disconnect it to see if it helps.
glyn4,
Jan 21, 11:02pm
Just been down to the car. 1.6GL. It's a normal round barrel downdraft carb, bog standard. It;s a NZ new car. 16V motor, squarish type of cam cover. They had those carbs on till the early 90's I think on the NZ stuff. Just taken all the air filter gubbins off and it does the same. What it;'s doing is quite weird. Start it up (after leaving for 10 mins. Runs like a champ, perfect. As soon as the choke stops it gets rough then surges up and down, almost like dirt is blocking then up blocking a jet, over and ove. It does this for a min or so then stops. I'm wondering how easy it is to get into the float bowl. Do I have to take the whole carb unit off the car, or just take off the top etc! Cheers again.
franc123,
Jan 21, 11:15pm
Blocked or partially blocked idle circuit.You could try taking the mixture screw right out and blowing gently back through the passage it sits in with compressed air.Given how old it is it's probably got issues with the carb gaskets flaking and clogging things up.Also have you checked for any air leaks around the manifold, vacuum ports etc!
mechnificent,
Jan 21, 11:15pm
I really doubt it will be dirt. that is a thing of the past pretty much. Water you can drain. If it is a normal old fashioned twin choke carby there will be bungs underneath the float chamber. If there is any blockage in the idle jet it will be in the idle-cut solenoid which you can screw off the side of the carby and I'm pretty sure the blocked jet comes out with the needle, if not the blockage will be just inside there where the needle had been seated. Have you checked all the small vacumm hoses and the diaphrams on the carb and on the distributor(assuming it has an advanceer)!
mechnificent,
Jan 21, 11:17pm
Yup, what Franc says too. check the manifold bolts are tight, carb is tight, screws on top of carb are tight. If you take the carb apart you will likely need an overhaul kit and they can cost a hundred bucks and more these days.
ginga4lyfe,
Jan 21, 11:24pm
I would say try sneazing the carby! , how you do this is by swapping plug leads 2-3 over and taking the air filter far away form the carby ( spits fire ) and start the car up and gently rev the car up and let the revs drop and just before stalling rev it back up, this should make it backfire through the carby and hopefully clear out the venturi, after you have dont this a few times, swap the plug leads back to how they were and then start her up and try her again, if this works then you had a blocked venturi, and will need to pull the carby off to clean the crap out , if it doesnt, then maybe the crap hasnt been cleared properly, or you have a really bad vacuum leak
glyn4,
Jan 22, 12:07am
Is the mixture screw the one which has a small nylon wheel at the end you can turn by hand! If so do you know what the standard setting of that may be! Since I've been turning it, thinking it was a tick over/idle adjustment screw! Thanks.
kiwis0,
Jan 22, 12:14am
Have you changed the fuel filter!
glyn4,
Jan 22, 12:57am
Yep, changed the fuel filter and the air filter. The carb throat looks real drty. If I squirt carb cleaner in there, will it hurt the motor at all!
mechnificent,
Jan 17, 1:52am
The screw wheel is the idle speed. The idle mixture screw will be either a screw with a nylon collar around it to prevent it being turned more than one turn(unless a mechanic has removed the collar), or, it will be a sort of oval shaped end that really need a special tool, but I doubt it will be that sort. The mixture screw will be low down on the carby too, lower than that idle speed screw, and nearer the middle of the primary venturi.
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