Hello all, I have had my SR5 for 15 years and try to stay away from complicated repairs, but they are catching up to me. Like getting a carb rebuilt. I know a Chevy kit has just a few parts and a Toy kit has like 30. So anytime I get ambitious, I go to O'Reilly's and shake the Toyota Carb Rebuild Kit box, and that feeling passes me.

I saved up and had a "Performance Garage" from somebody that works and races Toys, do a carb rebuild for me thinking "I'll let an expert do it, someone who speaks Toyota" and lets just say, he's never allowed to touch my truck again. 600 bux later, having worse probs now. He did replace the fuel pump and the corresponding vacuum hoses to get it to run. They were cracked out due to age.

My ? is: The air/fuel screw. Clockwise makes it run leaner? Cutting off the flow of gas?

He said he turned it a hair above Toy specs because I was running big tires. I had to pump and pump the gas and it would rev the first time and die. them pump and pump to get it going. OK, I did the rebuild and now it doesn't want to start without a shot of ether in the intake hose and then will die if I don't hold the pedal until it's warm. Also when I picked it up the shiny new sightglass on the carb was halfway full. now a month later it's always empty, I thought it was an air leak sucking it back into the tank. The few hoses he replaced seem to be intact.

So UP the idle a hair and adjust the air\fuel screw? is what I'm thinking. But going around town now, shifting, switching between gears it will stick to a high rev on occasion until the gears pull it down again. My auto choke stopped working years ago, so that's on the list but for now, I just need help with getting my idle reigned in. Thanks.

 

That guy doesn't know crap if he thinks that adding fuel compensates for larger tires. If you don't have emissions then I would recommend going to a Weber. Stock Aisin carbs can be a real pain in the ass even for people when know what they are doing. I've tune carbs on all kinds of makes of cars, trucks and motorcycles, but none were as tempermental as the Aisi carb.

If you are going to try to tune your aisin carb then I would try to get it warmed up, make sure the choke isn't engaged, and start with the leanest mixture possible without stalling. Then adjust the throttle to get it to idle properly around 800-900 rpm. Then go back to the fuel mixture to get the upper end of the RPM range dialed in. Then check adjust the throttle tension again to bring it back to the proper idle. Once you have the warm mixture and throttle tension set, you can let it cool and try to figure out your fast idle (choke) mixture.

 

you cant adjust idle mixture, you can only do idle speed. if you think your automatic choke is bad then get a new one. without this working it will be even harder to start. do u pump the gas a couple time before trying to start it? Well you should verify if this mechanic did the right job. look down the carb and snap the throttle linkage. you should see fuel squirt. You can re-adjust the float bowl your self... you dont need to buy new gaskets if it was just recently done and its pretty straight forward. check all your vacuum lines and the carb base for leaks as well as checking all the carb parts for operations. if EVERYTHING checks out fine you have a computer problem........................

 

Thanks Kawazx636 and Old blue. I'll check out the card over the weekend and since I had someone cut into my fuel tank hose to siphon out the last 8 bux I may have dirt in the tank that got in the steel line(or so it was suggested to me) to drop the tank when it gets low on fuel and see if there's a clog since it might be a throttle/fuel prob getting to the sight glass.

 

OK, so checked throttle linkage and no fuel squirting. Someone suggested taking the rubber hoses off the fuel pump and blowing through with an air compressor to see if there is a clog. instead of taking off the tank. Is this a good idea as having an external pump(not in the gas tank) and hopefully won't blow out one-way valves or anything?

 

You should have a mechanical pump on the passenger side of the head, not an electric pump in the tank

 

When you did the test was the sight glass on the carb half way? could you see if the was fuel in the float? if theres no fuel in the bowl then the fuel cant get into the auxiliary acceleration pump (AAP). Maybe you should do the float adjustment yourself if this thing is not running and your skeptical of the rebuilder. You should have your auto choke working. pretty simple check. When its cold take off the air cleaner to see if the choke is closed. turning the idle speed screw clockwise increases idle speed. these carbs run what, 5-7 psi? im not sure but its low compared to fuel injection

 

OK sightglass is halfway. I blew back through the rubber line connected to the incoming fuel filter. I didn't mess with the fuel pump. Replaced spark plugs B8ES's new plug wires and cap and rotor. It blazes down the road like a rocket now but still dies if I take my foot off the gas. Will up the idle as the choke is closed on cold start. I just don't know how many turns on the idle before it starts getting stupid.


Thanks Blue,Kawa.

 

look at my ecu thread. wiggle the connector to the ecu and see if that makes it idle.

 

Where exactly is the ECM on my 81? I don't see any box with a wide electrical plug under the hood. Also running around town, when I park the level in the sightglass is low on the glass. Maybe a quarter of the whole glass. Not halfway. I turned the idle up two turns but it was backed pretty far down almost to bottoming the spring out with 2 turns left on it(which would be completely off. The lowest idle I assume). So, I have 4 turns and it seems to be running ok in town. It just won't start sitting 4 or more hrs and the sight glass seems lower. Maybe the floats?

 

ya float could be it. ecm is driverside kick panel. (by fuse box)

 

OK, ECM is in pristine condition. Had to max out the idle screw just to get it to idle normal. So, I need to get the carb out to adjust the floats? It still dies when it is first started and still needs the starter fluid to get it going if left overnight. checked the manifold tightened up the bolts. Iv'e had it get loose before and sound like it was dying a slow death,

 

OK, so back in the shop... a different one. (where the guy knows what he is talking about as he iterated some talking points we've already gone over here) and says that there seems to be a missing piece.a check valve that allows gas to go into the pre ignition chamber... you know, the reason why there is no fuel squirting in there. he says that 2 of the three tips are there but the 1st guy may have turned the carb over and that piece fell out. Or my theory and it walked of in a shop that services mainly...Toyotas. So my question is? Is there a check valve or can I get a replacement? The current mechanic says it wouldn't be in a rebuild kit.

Any ideas?

 

UPDATE: The 2nd mechanic found the a piece on the carb had fallen in to one of the ports, blocking the fuel from passing through uninhibited. He fixed it. It now starts up flawlessly, every time. But now it won't stay idleing.

He checked the compression and found that #4 is at 90psi and #3 is at 120psi. He said these are supposed to be at 150psi. For another 100 bux he can inspect and adjust the valves to see if they got sucked in or if there is a burnt rod.

Last oil change I switched from Castol 10-40 to what I use in my big truck, which is DELO 15-40. I figure this may be the cause as the viscosity is thicker. But with Redding summers of being well over 100 degrees, if there are any pinhole leaks, I figure the thicker the better, but jap technology may not have had this in mind.

My question is: I read the Hanes Manual and think I can do the job to adjust the valves. Just pop the cam cover off and set the stroke to the TDC position, finally use the flat blade feeler gauges I have had in the garage for 20 years for this and unlock the locking nut adjust it with the gauge in there and lock it down going from one set of valves in order until complete. It seems pretty straight forward. Is there anything I need to take into consideration before doing this?

Thanks,

Mike

 

Burnt rod??? Sounds like you may have found another mechanic that doesn't know what he's talking about if he's saying you might have a "burnt rod" causing your problems...

Lashing valves is easy but that isn't a guaranteed fix. If you have carbon buildup on your valves and valve seats then lashing your valves will do you no good. In that case, your problem is on the block side of the head.

 

Oh, I think he was referring to the fact it was stalling and the compression was all out of whack. If he couldn't fix it by lashing the valves then he suggested I might have another prob, like a burnt rod or something. I am going to do an oil change tomorrow and switch to the 10-40, then lash the valves. I am hoping it was just the thicker oil sucking them in. Thanks Kawazx636.


As always, i'll post the results...