Well I took the plunge and finally bought my dream car. It's a silver with red interior 93 FD, and it's a bit of a fixer upper. It sits at a 1500rpm idle and never comes down, and kinda misfires a bit. Other than that the car runs great as far as I can tell. I think it has a vacuum leak, and I found a hose that goes to the back of the intake mani that is disconnected. Does anyone know where this hose is suppose to go? It's the hose that has the little HKS filter on it. If this isn't causing the problem, any ideas?





Thanks,

Ryan

 

If you are referring to the long, 1" diameter hose that runs parallel to the intake 'pipes', that is the feed to the split air secondary injection. It should have a filter on it. The air pump should have a filter also since both are feeding air into your engine.

Speaking of air filters... it doesn't look like one of the HKS mushroom air filter / intake thing does NOT have a filter in it! Pretty frightening. It should have a foam filter under the hard metal cage.

Regarding the 1500 rpm idle, post some close up pics of the thermal wax rod and where the ISC normally resides. Use the FSM and the 3rd gen FAQ thread to learn more about both the wax rod and ISC.

 

The service manual is a really good source for finding out where things are supposed to go and how things work check it out.

https://www.rx7club.com/3rd-gen-archives-73/tech-manual-directory-614824/

The service highlights manual is good.

 

A list of known modifications, such as whether your on the stock ECU or a standalone like the PFC is sometimes helpful. The car appears to be mostly stock, but just wanted to confirm.