Horse Newbie 7,070 #1 Posted October 21, 2022 (edited) Buddy of mine has a 1984 Toyota, 4WD, 22r,5 speed manual Replaced carb, it won’t idle smooth after the choke kicks down… Any suggestions what it could be ? PS… I have a 1981 Toyota 4WD, 22r, same engine, that I am about to start tinkering with… Any answers may help me in the future… Thanks for any advice… Edited October 21, 2022 by Horse Newbie Share this post Link to post Share on other sites
ri702bill 8,325 #2 Posted October 21, 2022 The 22R is a great durable engine - drove a 1978 SR5 for 2 years at work - great truck. Vacuum leak ??? Check the hoses and connections using a spray hydrocarbon (like WD-40) with the engine running. When you find the bad spot, the idle will smooth out as it sucks the additional fluid in...... 3 1 1 Share this post Link to post Share on other sites
Horse Newbie 7,070 #3 Posted October 21, 2022 @ri702bill why WD40 ? How about brake cleaner ?… Share this post Link to post Share on other sites
ri702bill 8,325 #4 Posted October 21, 2022 3 minutes ago, Horse Newbie said: why WD40 ? How about brake cleaner ? You want to use a spray that will not be detrimental to the rubber or plastic parts. WD-40 is pretty mild... 2 1 Share this post Link to post Share on other sites
Horse Newbie 7,070 #5 Posted October 21, 2022 That’s why I ask you guys… thanks a million! Share this post Link to post Share on other sites
Horse Newbie 7,070 #6 Posted October 21, 2022 Anybody else wanna take a stab ? Share this post Link to post Share on other sites
Pullstart 62,900 #7 Posted October 21, 2022 That was my first thought too. Intake leak? Vacuum hose leak? If not, is there any adjustment to idle on the carb? 1 Share this post Link to post Share on other sites
Pullstart 62,900 #8 Posted October 21, 2022 Fuel filter? How’s it drive? 1 Share this post Link to post Share on other sites
Bill D 1,922 #9 Posted October 21, 2022 Is something wrong with the replacement carb? Rebuild the original carb and see if the problem goes away. 3 Share this post Link to post Share on other sites
Horse Newbie 7,070 #10 Posted October 21, 2022 (edited) On 10/21/2022 at 5:24 PM, Pullstart said: That was my first thought too. Intake leak? Vacuum hose leak? If not, is there any adjustment to idle on the carb? Yes, there are adjustment screws on the carb, but the people that he ordered the carb from says no need to adjust as they mount their carbs on an engine and adjust before they ship them… I told my buddy that that’s a crock, you may have to adjust for your specific engine. I was thinking that if it idles good with the choke on, then idles rough with the choke off , then it is getting too much air when the choke plate opens… Sound right ? He is very hesitant about turning those screws, but I told him he can always put the screws back where they were… Edited October 22, 2022 by Horse Newbie 1 Share this post Link to post Share on other sites
Horse Newbie 7,070 #11 Posted October 21, 2022 (edited) 13 minutes ago, Pullstart said: Fuel filter? How’s it drive? Drives well at higher rpm/ going down the road… then cuts off when you come to a stop… when you crank first thing in the morning idles fine until you kick down the choke, then idles rough…fuel filter has been replaced… Edited October 21, 2022 by Horse Newbie Share this post Link to post Share on other sites
squonk 41,120 #12 Posted October 21, 2022 What was it doing before the carb swap? I would do what everyone says so far but I would try to isolate which cylinder is misfiring. Once that is determined do a compression test on that cyl. If ok again look for a vacuum leak on that clyinder's intake runner. It sounds lean but I would check cylinder condition. If you got a low one adjusting the carb will be like takin a leak into a fan. 2 Share this post Link to post Share on other sites
squonk 41,120 #13 Posted October 21, 2022 Higher engine speed can mask a weak cylinder. How many miles on this thing? 1 Share this post Link to post Share on other sites
Horse Newbie 7,070 #14 Posted October 21, 2022 13 minutes ago, Bill D said: Is something wrong with the replacement carb? Rebuild the original carb and see if the problem goes away. He says it is acting the same with the new $500 carb as it did with the old carb…with the exception that it does a little better going down the road… I told him to get a carb kit and try to clean/ rebuild old carb before he ordered the new carb ! Share this post Link to post Share on other sites
Horse Newbie 7,070 #15 Posted October 21, 2022 4 minutes ago, squonk said: If you got a low one adjusting You mean a cylinder with low compression ? Share this post Link to post Share on other sites
Horse Newbie 7,070 #16 Posted October 21, 2022 4 minutes ago, squonk said: Higher engine speed can mask a weak cylinder. How many miles on this thing? Probably about 140-170k, but that isn’t too bad on a 22r right ? Share this post Link to post Share on other sites
Horse Newbie 7,070 #17 Posted October 21, 2022 6 minutes ago, squonk said: What was it doing before the carb swap Basically the same symptoms, but it’s running good at cruising speeds, then dies at a stop… Share this post Link to post Share on other sites
squonk 41,120 #18 Posted October 21, 2022 (edited) 6 minutes ago, Horse Newbie said: He says it is acting the same with the new $500 carb as it did with the old carb…with the exception that it does a little better going down the road… I told him to get a carb kit and try to clean/ rebuild old carb before he ordered the new carb ! That tells me it's not fuel related. Sounds more like vacuum / leak weak cylinder Edited October 21, 2022 by squonk 1 1 1 Share this post Link to post Share on other sites
squonk 41,120 #19 Posted October 21, 2022 At Idle speed the engine vacuum is at it's highest. You need that vacuum to pull fuel though the idle passages on the carb. It would be nice to hook up a vacuum gauge to the engine. It would tell a lot. Could be late valve timing/ worn chain, leaky valves, late ign timing ect. 2 1 Share this post Link to post Share on other sites
oldlineman 1,481 #20 Posted October 21, 2022 (edited) Yep, I vote for vacuum leak as si702Bill said and then check cylinder compression like squonk has stated, only because spraying some WD 40 is easier and faster. Yes can be many things with that kind of mileage. Edited October 21, 2022 by oldlineman 1 Share this post Link to post Share on other sites
Horse Newbie 7,070 #21 Posted October 21, 2022 Thanks guys… I’ll pass it along to Mr. Goodwrench ! PS… I’m sure the shared information is putting us on the trail… any more ideas, throw them out to me… Share this post Link to post Share on other sites
squonk 41,120 #22 Posted October 21, 2022 (edited) If that truck has an EGR valve, it could be stuck open. That would cause your symptoms also. Major vacuum leak, Edited October 21, 2022 by squonk 2 1 Share this post Link to post Share on other sites
Horse Newbie 7,070 #23 Posted October 21, 2022 2 minutes ago, squonk said: would be nice to hook up a vacuum gauge to the engine Where do you hook it up ? He has a Chilton manual for the truck… that would probably tell how, correct ? Share this post Link to post Share on other sites
Horse Newbie 7,070 #24 Posted October 21, 2022 Just now, squonk said: If that truck has an EGR valve, it could be stuck open. That would cause your symptoms also. Major vacuum leak, I believe it does have an EGR valve… I have suggested he check that too … Share this post Link to post Share on other sites
Pullstart 62,900 #25 Posted October 21, 2022 It wouldn’t hurt to read the spark plugs. That might tell which cylinder is acting up if it is isolated. When they read race car plugs, they shut it down fast from high rpms and a hard pull. This should be easier to tell which cylinder is suspect without high revs. 2 Share this post Link to post Share on other sites
