I've done some research here and a couple of other RX-7 Forums, but I was unable to figure out why my car will not idle.

So I took it to a performance shop. The mechanic checked things over for about 10hours. By the end of it, he looked at me and said, "**** it, sorry but I can't figure out what's wrong."

The things that have been looked over are vacuum lines and some of the sensors. A visual inspection and spraying brake cleaner in the engine bay (and perhaps from under the car) was done to find a vacuum leak. The mechanic stated the car acts like it has a vacuum leak, but he can't seem to find it.

This is an 87 T2, the car cranks and with proper throttle feeding the car can be driven. In fact the throttle cable is yanked back sufficiently so the car will maintain high enough rpms on its own to not die. Note the rpms needed is 1200+, anything around the stock rpm level and the car shakes pretty bad.

I'm pretty much at a loss. Is there some place that most likely haven't been looked over, where a vacuum leak could exist or something else I or the mechanic haven't thought of?

 

You may just have very very low compression. In that case it will not idle at stock level. Did he try a compression test in both housings? If it is a vacuum leak it will have to be large one such as the one behind the intercooler for the brake booster. If that is off, it will not idle (been there). If you have a boost gauge hooked up, the needle will bounce like crazy if it does have low compression. Not sure what else it could be since you are able to drive it. In some cases with high mileage motors, there would be so much carbon imbedded in between the apex seals that there would be very little compression. It's hard to tell if the motor is just worn out or carbon lock. ATF(auto trans fluid) does the trick if it is. Try squirting in some (about a capful into each housing) and let it soak over night. That usually breaks up carbon as it softens it up and blows out when the car is started and revved. Other than that, I have no clue.
Good luck.

 

By the way, I'd be weary of taking it to a "performance shop" as almost all don't know crap about rotaries.
They think because they are selling and installing performance parts, they are entitled to being a "know-it-all-mechanic". Usually there's zit faced kid that acts like it.
Find a rotary shop near you. Your best bet is post on any RX7 forum and hope someone can figure it out or had similar problems as you do.

 

have you done a compression check , how many miles are on it ?

 

symptoms sound exactly like my car... Will not start or idle at all unless I baby the throttle. Compression from 82-95 in the front rotor...ZERO compression on the rear. Hope your luck is better than mine.

 

The motor's compression was supposedly checked before I bought the car. I guess there is a chance the seller lied to me. However the car drives very well and pulls nicely.

I can't say the vacuum hose behind the intercooler was checked, but during the times I walked in the garage to check on the progress the mechanic appeared to giving things a thorough look over.

Carbon lock isn't something I would figure my no idle problem to be. The car cranks and without enough throttle will stay running. From the research I've done I thought when a motor is experience carbon lock it would crank or run period. However if I'm wrong I'll give it a shot. At this point I'm almost willing to try anything.

A valid point on the perfomance shop post, however I'm inclined to trust the mechanic that looked my car over. He's a former FC owner himself and within the last year put in a rebuilt motor for the one other T2 owner that lives in this city. Additionally, for the 10-12 hours that the mechanic searched for the source of my idle problem. I wasn't charged a single dime. His words, "I didn't fix a damn thing and not going to charge you for it." Pretty hard for me not to trust a mechanic that follows that line.

The motor was swapped so I'm unsure how many miles are on it. The previous owner claimed 30k-40k if he lied on this point and the car still has the original motor then it would have 106k miles.

Heh, well prior to knowing that these problems actually existed, I launched it twice and ran it for a quarter mile to see what RPMS would provide the best launch and what my speed would be at the finish. The car displayed it's potential for speed. It pulled well enough that I doubt the rear rotor has no compression.

Well, I got some pointers on places to check, thanks for the help!