foaxaca

Alright all you 3rd gen pros, any help with this one would be appreciated. My son's RX7 is a '94 touring model with no mods except an HKS cat back so far. Engine was rebuilt about 20,000 mile ago (car has about 125,000 miles on it now) according to seller. Over the past three weeks a problem has cropped up especially on cold starts. Car starts and idles high just like the auto warmup function tells it to do and then as soon as you back it out of the garage idle starts to drop, it nearly stallls and then check engine lite comes on and idle recovers briefly. Then the dropping idle/check engine lite/idle recovery cycle starts over again. If you keep it alive and start driving it, at the first stop, car dies and really struggles to start. Last time it started after 5 or 6 tries and after a big puff of white smoke and then drove great to the local shop for diagnosis and repair. Drove with the A/C on just to bump the idle up a bit but no problems - boost was fine, accelaration was fine. I've tried starting it in gear with clutch in to disable the AWS but no difference. Any suggestions? I've doen some research and read it could be anything from the TPC, ISC or any one of several other RX7 acronyms. I've got no problem getting my hands dirty in a non-rotary engine but this is our first rotary and sometimes I feel like I'm working on an alien spaceship when I get under the hood so bear with me.

Gadd

first thing is to check for engine code/s, Anytime the check engine light comes on there should be a code set. That should point you in the right direction.

http://www.fd3s.net/engine_codes.html

vellj001

Very similar conditions I have. However my car always stayed on high rpm once warm up. Just in case check the intake and outgoing coolant pipes to the auto choke to see if they are clogged. That was the root of all my other syntomps. Started with engine dying, on cool start struggeling to stay alive, hi rpm idel once hot, after white smoke due to extra fuel being mixed with oil so that he oil was thinned down and was spillling from my BOV and exhaust.

Another simple things is to check if the valve to the fuel mapping sensor is clogged or not. Shake it and see if it rattles. If not it is clogged and could cause some of the problems. Mine was too.

Could be other things but there is not loss in checking out.

level7

iTrader: (3)

Sounds like a bad clutch switch to me. Ive noticed on my FD that if it just about dies but just bairly catches idle it throws a code but will go away. One symptom of a bad switch is less then satisfactory idle conditions when the clutch pedal is pressed from a stop. There are two switches, the one your looking for (if this is indeed your problem) is under the dash by the peddle area. Just thought I would put this idea out there incase your still looking for things to try.

DaleClark

iTrader: (55)

Another possibility is the coolant temp sensor for the ECU. This richens the mixture when the car is cold - if it's bad or unplugged, the car will run terribly while cold, but run fine when at operating temp.

Pull the codes before you go any further.

Dale

foaxaca

Shop diagnosed a faulty coolant temp sensor as my problem. They also tell me that access is very difficult (under the alternator). Any idea of what the part costs and how much of a challenge replacement is?

foaxaca

To continue the story, shop in Ontario (GT Motorsports) took 4 days just to come up with a diagnosis. Price they quoted was $600 plus parts!! For replacement of a single sensor. They seem to be much more performance oriented and not really interested in more standard diagnosis and repairs. Anyways, Montego recommended R & R Rotary Specialist in Upland which is just a few miles from where I live in Rancho Cucamonga. Another great call from a member!! Steve took the car today (Saturday) and called me back with a full diagnosis (engine temp sensor bad), great price on the replacement (over $400 less than what other shop quoted), a great price on a full tune-up AND a great offer to install a quick cooling fan mod that has them turn on a a temp 7 degrees lower than the stock switch does. All this and will have it done on Monday. Otherwise, he said the FD is in good shape which is good news. Thanks for everyone's help - this is a great resource. Hopefully as my son and I learn more about our FD we can return the favor.