I need to wait another month before starting it.

BTW, I can't see the link between the idle surging and the radiator fan!?

Thanks for your help it's really appreciated!

 

... but I need to say that when the engine was cold and I started it, I did not have that bouncing idle for the first 20 seconds.

 

Radiator fan is an electric current. Everytime you turn your ac on, the fans turn on.
Basically, I wanted to know whether or not if the fans turn on by themself to cool the radiator, will your idle still bounce.
I didn't read everything in this thread. But why can't you start your car for another month?

 

Flooded it, I tried cleaning the plugs but didn't work. I had the same issue last winter. I'll start it on compression once again, I'm on the top of a hill anyway.

I'll need to check 3 things for my bouncing idle

1. Boost sensor. I bought a new one so it'll be easy.
2. TPS (Already checked it but I'll restart).
3. Wiring harness. I know there's 3 cut wires, but I don't think this is the problem.

 

Oh and I forgot to mention something...

When I unplug the boost sensor, nothing happens (idle is still surging).

When I remove the hose from the boost sensor, idle is OK at 1,100 RPM, but black smoke is going out of the exhaust.

 

Sounds like you have a grounding problem especially if you are using a stock based ECU. I've seen several FD's that have had an idle surging problem that was caused by grounding issues.

This thread:
https://www.rx7club.com/3rd-generation-specific-1993-2002-16/i-need-some-expert-help-818806/

the issue was the ground wire not attached to the exhaust (I helped him in PM's). If you have wires just exposed or other grounding issues, that can cause the symptoms you are experiencing.

 

My god, first time I read about this possibility! Do you know exactly where I should check for this wire?

 

The exhaust ground usually goes on the main cat/midpipe to catback connection. If you have open wires on the main harness, you need to figure out what those go to as well as they could be a problem.

 

Hmmm I'll check this out too.
The only problem with the wiring harness is that the 3 open wires are pink........ nice puzzle.

 

vacuum

 

Highly unlikely due to the fact that turning on the ac will cure the problem.

To the OP- If you were to drive the car with the AC on and never shut it off, will the idle eventually start surging again?

Mahjik- Could his problem be related to the wax rod in the piece near the throttle body, for the life of me I cant think of the name of it and don't have my car to go take a picture. But I know from time to time those crap out and when the car is on a deceleration it will pull it more fuel then it needs and start hunting for air, thus the surging.

 

No, the idle will never surge if I put the A/C on.

 

I had the same issue after installing my powerFC using the base map; turning the A/C on (mine was broken, but still kicks the fans on high) would fix it; but as soon as the A/C was turned off the surging idle would return. I had my car tuned last spring and this has gotten rid of the surging idle permanently and regardless of the A/C being on or off.

 

I tried changing the map sensor, without success...

http://www.youtube.com/watch?v=YD5VjnnJsNw&fmt=18

 

I had the same problem just last week, There is a idle sensor under the top intake manifold, We just unhooked the connector and it has worked fine ever sense.