Found this is the manual as well. I did a half turn of the screw and now I’m idling beautifully. Thanks you for the tips and knowledge man I really appreciate it.You need to get a vacuum gauge. Required equipment for this engine. You can get one at any auto parts store.
It’ll show what the engine vacuum is and let you know if there’s any vacuum leaks.
If you can get the engine to idle smooth and not too fast by just pulling out the choke a tad, then maybe all that needs to be done is setting the idle speed on the carburetor a little faster.
It’s just a set screw you can access with a normal screwdriver. Super easy - once you find it.
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These trucks will run under many conditions even if it's unhealthy. They're pretty beasty like that. I've seen trucks "run" with vacuum leaks. I've had my truck running lean and rich for periods of time because of faulty emissions equipment. I've had vacuum lines routed incorrectly for years and still had my engine "working". It doesn't mean it was a healthy engine. If you're going to have the emissions equipment installed on your vehicle it's necessary to have it operating correctly or other issues can arise causing bad idle, rich or lean mix, or other issues that can be detrimental in the long run. After dealing with it for years and then removing all the smog equipment all together I can say that my engine runs better. Having no emissions control equipment is almost certainly better than having faulty equipment and having to re-rout vac lines to compensate. And it's true, that there are some ways to rout lines in a way that works, but it's not as toyota intended and it confuses the heck out of the next guy who goes to work on it, as we're seeing in this thread...
I was just working on those vacuum systems yesterday and can confirm you have it hooked up incorrectly. As @cps432 says, these engines can be adjusted to run pretty well even when things are not right. There are so many little adjustments that can compensate for or mask other issues. There are also entire vacuum systems that provide ancillary functions not directly related to how “well” the engine runs - like the distributor venting and HAI/HIC systems you’ve got plumbed incorrectly here.
They are, but “totally “ is the correct word. How you have it hooked up now, the HAI system is inop (which isn’t really an issue in warm climates) along with the Hot Idle compensation and the distributor venting plumbing has been disabled
The distributor venting plumbing HAS to be fixed otherwise say goodbye to your distributor as it corrodes to death.
@FJ60LC Regarding the EGR valve - the port that’s capped connects to the brown plastic EGR Modulator directly above it - you’ll see one port not connected on that. Disconnecting and capping both of those is a common fix when the EGR is not functioning well and causing running-rough issues. It’s ok to run with it that way, sort of.
The diaphragm on the carb can be capped off. The valve on the driver’s side wall can be left alone and disconnected. Looks like somebody removed or inop’d an AC system at some point. I’d look in the manuals for AC system diagrams and make sure everything else is capped off or dealt with too.
Back of the emissions FSM has instructions on adjusting the carb using the “lean drop” method. I pull the air cleaner off for easier adjustment of the idle mixture screw … and if you’re that far you may as well pull the valve cover and set the valves.
@OSS knows a LOT more than I do about these trucks so I’ll defer to him (and others).Thanks for the tips. I have one quick question maybe you or @OSS can help me with. I’ve been digging through some threads and it seems like a malfunctioning egr can mess up the distributor. If we are assuming mine is broken since it is capped should I get a new egr set up or recurve the distributor?
Again I’m not in a county where I need to pass smog.
That tee fitting should have a hose connected to it and the HIC valve under the air cleaner cover.
If your HIC valve is gone or inop, plug that tee fitting pipe that’s connected to the PCV valve. It’s a huge vacuum leak when open. That’s why the engine isn’t idling nice.
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While you guys sort out which vacuum hose goes where, I’d like to suggest that you replace that crusty looking PCV valve (12203-61010) and the rock hard grommet (90480-18180) with new parts.
Links to posts?