Aussie_KE70 Posted July 16, 2015 Report Share Posted July 16, 2015 (edited) Hi all, Just after a little guidance/ assistance. Now I have used the search function and it has not helped, hence the questions. The KE70 I have has a standard 4K-C and carby on it. I'm about to put a carby kit through the carby and clean the damn thing, as the car will not idle and I suspect that the idle circuit in the carb is blocked or there is a restriction. Now I have checked the timing without vaccum assist and its at 8 degrees, cleaned the points, spark plugs and dizzy cap and rotor button. The valve clearance have been just adjusted, I have replaced the fuel filter and cleaned the fuel line between the tank and filter with compressed air. I have replaced the fuel line between the fuel pump and fuel filter and I have clean the fuel line between the carb and fuel pump. Now reading the Toyota engine manual, under tune up it talks about removing the vac line to the HIC valve and block the hose and remove the var line to the Air Injection check valve and plug the vac line. Now for the life of me or its my dyslexic day I am trouble finding both of these. I am assuming that HIC = High Idle Control, now the only check valve that seem to replicate this is a green valve that attaches to the air cleaner on the passenger side of the vehicle. Is this it ???? And I have no Idea where the Hell the AI check valve is ??.......... I can see the Exhaust Gas Re-circulation Valve but from my experience these are usually 2 different things. One channels exhaust gasses back into the engine the other usually pump air into the exhaust like what was found on the Holden VK commodore black 202 engines. I have upload the page I'm referring to in the manual below. Thanks in advance. Cheers Luke Edited July 16, 2015 by Aussie_KE70 Quote Link to comment Share on other sites More sharing options...
altezzaclub Posted July 16, 2015 Report Share Posted July 16, 2015 (edited) First, go and see if the electrical idle shut-off valve is working. It should, 'click' when someone turns the ignition on and off. If it is disconnected or broken, the car won't idle... Perhaps it was disconnected when the carby kit was put through. Edited July 16, 2015 by altezzaclub Quote Link to comment Share on other sites More sharing options...
Aussie_KE70 Posted July 16, 2015 Author Report Share Posted July 16, 2015 Cheers I'll check that tonight Quote Link to comment Share on other sites More sharing options...
Aussie_KE70 Posted July 22, 2015 Author Report Share Posted July 22, 2015 Okay so the electrical idle shut of is working correctly, I stripped the carby down last night and it was full of crap throughout the bowl and the jets were partially blocked. Now I did notice that the idle mixture screw had been damaged by screwing it in to hard, ie there is a ring impression around the taper. How crucial is this?? Quote Link to comment Share on other sites More sharing options...
altezzaclub Posted July 22, 2015 Report Share Posted July 22, 2015 It shouldn't be crucial, but I expect it will be a coarser adjustment than factory now. Make sure you clean the drillways out behind the jets too. I use a syringe (no needle) full of petrol to squirt through them, but anything that hoses solvent through will do. The cans of carb cleaner are good, and even an air-gun if you have a compressor. Quote Link to comment Share on other sites More sharing options...
Aussie_KE70 Posted July 22, 2015 Author Report Share Posted July 22, 2015 cheers thanks for the heads up, the carby in its bits and pieces has been soaking in petrol all day, I have a couple of cans of Nulon carby cleaners and I have a compressor. Its all going back together shortly, later this arvo hopefully by this time tomorrow I'll have some good news :thumbsup: Quote Link to comment Share on other sites More sharing options...
Aussie_KE70 Posted July 22, 2015 Author Report Share Posted July 22, 2015 (edited) Okay so last night at 12am I had the carby back together and on the car, first hit of the key and it fired and ran on the hand choke. So I adjusted the base rpm screw took the hand choke off and it began to idle....... bonus..... BUT at idle ie 750-1000 rpm it has developed a slight miss, but under load, ie put it in gear (its an auto) and with the hand brake and foot brake on and pull the choke out to increase the rpm, it idles without a miss. So I attached my wide band O2 sensor to the exhaust to see what the mixture was and I attached the vacuum gauge to the carby. Now the vacuum is sitting at 30 inches of mercury (please ignore my ignorance but is that normal or low????) And the AFR was sitting at 18.7 which is about 0.5% CO emission at around 900rpm which is really lean, now I tried to adjust the mixture screw and it made 0 difference. I have checked the timing again - its sitting at 8 degrees at 900rpm, valve clearance are correct and I have not found any vacuum leaks (checked with a few sprays of "start ya bastard"). My questions are; 1) 30 in Mg is this in the normal range for these engines ? (I know that there are many variables that effect this) 2) Is the AFR sitting at 18.7 normal? given that 1% of Carbon Dioxide is usually only recorded between 14.7 and 15.2 AFR (Engine manual states to tune idle to 1% CO reading at 750 - 800 rpm) 3) In my experience a miss at idle with no load indicates a vacuum leak but it also could be an incomplete combustion due to the lean AFR? thoughts Edited July 22, 2015 by Aussie_KE70 Quote Link to comment Share on other sites More sharing options...
altezzaclub Posted July 22, 2015 Report Share Posted July 22, 2015 30" of mercury is a full vacuum, and that would be correct as at idle as the throttle plate is shut and the inlet manifold under max vacuun. My AFR moves up and down from 14.7 to 18, that being a mix of the SU carb characteristics and the cam makig idle grumpy. 16-18 is lean, but I cruise at 100kph at that and go up slight hills until I push the throttle down. With adjustable jets on the SUs I have set them to be that lean at idle. Your leaness might be from the groove in the idle needle, it lets in too much air no matter what you do with it, or maybe a tiny leak somewhere. Being lean like that makes the electroics work hard as its harder to fire a plug. So spark plugs, leads, dizzy components ... any weakness will show then, apart from a leak, as you say. Thne again, its a 35year old motor, a miss at idle is not much to worry about! Quote Link to comment Share on other sites More sharing options...
Aussie_KE70 Posted July 23, 2015 Author Report Share Posted July 23, 2015 To be honest it is 100% better than what it was 2 days ago BUT at idle it will stalls when putting it into gear, the only way that I can get it to hold idle in gear is with the hand choke. I am attribute this directly to the AFR's being too lean. If that's what it has to be, well so be it but I would like to get it to idle in gear with out the choke. I don't suppose you know where I could located another mixture screw?? I have checked the local wreckers here in Gippy with no luck Quote Link to comment Share on other sites More sharing options...
Aussie_KE70 Posted July 23, 2015 Author Report Share Posted July 23, 2015 Do you think it is possible to re-profile the screw?? Quote Link to comment Share on other sites More sharing options...
altezzaclub Posted July 23, 2015 Report Share Posted July 23, 2015 You could re-machine it so it screws in further to touch the seat, if it is long enough. There must be hundreds lying around, I gave my stock carb to a mate when I fitted the SUs, and I think its lying in his shed. I'll ask him if I remember. My auto was also a pain going from either too high an idle speed in neutral, or stalling when put in drive, especially when cold, which is most of the time. My solution is to fit a 4AGE, or option B is to hot the motor up with cam and quad carbs.... Set the idle speed to idle in gear when warm, which is what I did. I think it was about 800rpm, but then it goes up to over 1000 in neutral. Quote Link to comment Share on other sites More sharing options...
Aussie_KE70 Posted July 23, 2015 Author Report Share Posted July 23, 2015 I reccon I will use some 1000 grit wet n dry and re profile it as the marks would only be just deep enough to catch your finger nail, but I do remember it having a ridicules high idle before this started. At this stage the idle in gear would be around 800rpm with the hand choke pulled out around 1/4. Cheers thanks for your help. I'll give an update in a couple of days after the weekend. Quote Link to comment Share on other sites More sharing options...
Aussie_KE70 Posted July 23, 2015 Author Report Share Posted July 23, 2015 Well it turns out that I can get a new mixture screw for the carby for a hefty $27 from bursons. I'll have a brand new item in my hands on monday Quote Link to comment Share on other sites More sharing options...
GJM85 Posted July 23, 2015 Report Share Posted July 23, 2015 Is it possible the idle jet has a blockage? Quote Link to comment Share on other sites More sharing options...
Aussie_KE70 Posted July 23, 2015 Author Report Share Posted July 23, 2015 I have cleaned all that last night. The carby stripped down soaked in fuel for 24 hrs then I cleaned it with carby clean and compressed air. I paid particular attention to the idle circuit, jets and venturies of the carb. The engine manual specifically mentions that if the idle mixture screw is damaged by being screwed to far in against the seat, ie creating a circular impression on the taper that it is to be replaced. Quote Link to comment Share on other sites More sharing options...
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