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I recently purchased an 87 Toyota pickup, the 22r has a full smog delete from the previous owner. I noticed the Idle advance hose is still connected but the normal advance (closest to the radiator) on the vacuum advance was left without a hose and (uncapped). I assume this was done correctly based on what I know about the previous owner but was kinda questioning it, considering it could be causing a vacuum leak? (see photos below)
Along with that, I noticed a medium-size port at the top of the carb near the air cleaner which was left uncapped as well. I would appreciate it if someone could take a look through the pictures to assure me this is all correct.
To the best of my knowledge, it's the "outboard" vacuum port on the distributor that should have engine vacuum to it, on a desmoged version. The inner port is actually for timing retardation, and is a part of the original emissions system. Since the items that control it are either no longer present or disabled, there is no need to have engine vacuum hooked up to it. In fact, having engine vacuum hooked up to that port is only going to work against the mechanical advance in the distributor. Try getting a timing light & watch your timing marks through a few rev cycles in the current configuration, then switch over the vac line to the other port & look again. I'm sure you'll see a difference. The unused port of the distributor vacuum advance can remain uncapped with no performance issues, but you may want to cap it off anyway, to prevent and dirt or humidity from getting in there and deteriorating the diaphragm.
2nd picture - I don't think that is an open vac port. It looks more like a "boss" that was cast in for some purpose, but not used on your model. These are usually tapped inside to accept a bolt or screw, to attach something to the carb. To verify that it isn't a vac port, put your fingertip over it while the engine is running & see/feel if it sucks your fingertip to it.
4th picture - Is that large port part of the carb or the air cleaner? It's hard to tell. If the air cleaner, it's likely the inlet for the fresh air hose from the air pump. If the port is actually on the carb, that is also part of the old smog system. There shouldn't be any vacuum at that port either when running.
01-04-2021, 12:42 PM
