My car is an 86' base modle NA rx7, when i bought the car i was told it has had an engine rebuild on it with a rough idle. I am wondering how to fix the rough idle. It doesn't even sound like a rotary half the time and the plugs look good, close to no residue on them. Is there an idle screw that i could or shouldn't mess with. New to rotary and confused.

 

lol... drunk post.

13 years of experience beats drunk...

check for vacuum leaks, check timing,.

 

I'd check compression before I do anything..I learned that the hard way.

 

Ok about the vacuum leek, there is a vacuum hose going to actuator lookin thing on the exhaust/intake side of the block and its cut and blocked off. so could it be that? I know i need to brush up on my rotary engine parts and pieces.. I'll get the hang of this eventually.

 

you should also chek the TPS sensor and the idle screw and work with those 2. there is a FAQ that shows you a few things and basics
https://www.rx7club.com/2nd-generation-specific-1986-1992-17/frequently-asked-questions-2nd-generation-rx-7-faq-fc-494667/

 

Ok, looking throught that FAQ im thinking it might be the BAC but my car doesn't have AC, it did but was removed.. could that cause a problem. Because it talks about the AC having affects on the valve.

 

BAC *helps* control the idle. Sort of an Idle Air Control Valve. Only helps when the rpms are under 750-800 rpm or so.

BAC goes full open when the key is HELD to Start to aid in starting the engine. AFter that it enters a duty cycle to help maintain a 750 idle speed. HELPS is a key word.

The idle speed is set with the initial set coupler jumpered to put the BAC in a FIXED duty cycle so it won't befuddle you when you make idle adjustments. After setting the idle the idle speed should be approx 750rpm, then you remove the initial set coupler and the BAC might *hump* a couple of times and then settle down to aid in keeping a 750idle speed.

If the ACV has been removed there's a possibility there is a air leak there. Also there should be, on a early non turbo, two vacuum lines on metal nipples just above where the ACV sat. They might be causing a vacuum leak. They fed vacuum to the ACV.

The two small hose on front of the throttle body (three nipples one above the other there) might be crossed causing a vacuum problem. They are NOT both vacuum. One is filtered air going to the primary fuel injector bleeds. Put vacuum to the primary fuel injector bleeds and you have a problem.

Idle problems can't be fixed online is the bottom line. Get a can of starter fluid and spray willey nilley around the engine as it idles and find any leaks.

 

Alright will do, all of this is helping me a ton!! Thank you guys a bunch. Just one more question though.. There is a reservoir by the wiper motor that has a line that looks like it should run to a nipple that has been plugged. Problem if not connected?


I'm gonna apologize if im being ignorant in any way, im just new.

 

The resevior is probably the cold-temperature starting assist system. It sounds like it has been disconnected. Look it up in the online FSM, you will see what it looks like and will be able to tell if that is it.

Rough idle:
1. vacuum leak
2. idle speed
3. idle mixture
4. TPS adjustment
5. Timing
6. Check BAC operation

see the online FSM

 

well the tps had a wire broken, i fixed that. Still not idling right wanting to die.