SpenceOne

So my FC starts with no issues but sometimes it idles at 1500rpm, then the next time i start it might idle at 1000rpm or even close to 500rpm....its different every time i start the car. After a the car has been running for a bit or after good drive around town the car seems to idle just fine at 1000rpm. Im not quite sure whats going on. Also i can smell gas when i have the windows down at a light or when im warming it up in the morning. Is it running too rich? What can i do to troubleshoot these things? Thanks for your time!

misterstyx69

iTrader: (142)

Question.Do you have a Catalytic converter on the car?
If not then there is your "smell" answer"..
Also check the fuel distribution/lines etc on the engine ,especially the Fuel pulsation dampener,as it is prone to leakage and can leak fuel.(simple fix,replace or remove it from system).

If you start the car In gear,clutch in then the car will have a tendency to rev higher than the normal Idle speed which should be +/- 750 Rpm..Don't worry if you sit around 850 or so..
You can adjust idle to suit you too..it's not set in stone what is the absolute norm.
Try starting in Neutral,clutch in and see if that helps your dilemma..

(I may be backwards on the Idle thing,so try both ways..lol,,been a while...we get snow here!)

SpenceOne

Im fairly certain the car has no catalytic converter. We dont have emissions where i live and i know the exhaust has been replaced on the car. I will confirm that when i get off work.

Another thing is that when i start the car it might idle at around 1100 rpm for 5 minutes or so but as its warming up it will drop down to the 700-500 rpm range. is that normal for the car to do? It also sounds like its sputtering when idle...

Thanks for the response I really appreciate it.

WondrousBread

The stock Cold Start System works as follows. On cold start, the ECU reads the temperature from the sensors in the engine bay. If it is stone cold, the engine starts up and idles around 3000 for approximately 17 seconds, and then drops down. This is controlled by a solenoid on the side of the dynamic chamber. This cold start function is often removed (and good riddance, as it does nothing). After 17 seconds, or immediately if the car is already a little warm, there is a mechanical high idle. When cold, a device on the throttle body (called a thermowax) props the throttle butterflies open slightly so there is more air flow (and therefore a higher idle). It is usually around 1500 for me, but I am to understand this is higher than spec. Once the coolant warms up, and flows through the thermowax, the idle decreases. Once warm, the thermowax is disengaged and the idle should be around 750.

Now, the cold start system is often altered on these cars, so I wouldn't be surprised if the 3000 rpm high idle doesn't happen. Don't bother trying to restore it, the car will still start and drive perfectly well without it. Sometimes the thermowax is removed too, but as you said the idle decreases as.the car warms up, yours is probably in place. It can be adjusted, procedure is in the FSM.

It should be consistent though, not surging, sputtering, pulsing, or lumpy. The rotary engine does tend to have a "throaty" noise at idle, but if there is significant sputtering, misfiring, or backfiring, you have a problem somewhere.

The TPS can also go bad and cause weird idle symptoms, or it may just be out of adjustment. There are write ups on how to do this.

SpenceOne

Thanks for the information. It sounds like my car is starting correctly for the most part. I will investigate the sputter noise more. Thanks again!