I've got a minor issue with my idle on my Rx7. After warm up, the idle will slow down to about 1100 and stay there. If I goose the throttle to about 1800 and let off it will drop to 1000 and then to 850 where it idles like a champ. I checked the TPS today and noticed that on the narrow band I was seeing 5v at ~half throttle staying until full open. Not sure if that's normal or not. The wide band on the TPS is perfectly within spec. The low end of the narrow is also in spec. I do not have a vacuum leak because I have checked all my connections, listened for them, and sprayed carb cleaner for them. I pulled the ISC and sprayed it out. It wasn't really dirty at all. When I get it to hold at 1100, the throttle stops for idle are met on the throttle body which leads me to believe that it is not mechanical adjustment issue. After doing some reading, I have discovered that there is a system in place that checks the clutch position, gear lever position, and the vehicle speed to determine whether or not to idle or stick to 1100. When it does stick to 1100, I have tried depressing and releasing the clutch pedal and placing the gear lever in various positions with no change.

Anyone have any ideas? This is a BONE STOCK rx7.

 

A stock FD is supposed to idle between 750 and 780. I would start by lowering the idle from 850 to 750 and see what effect that has. I would also check your dashpot to make sure it isnt sticking some of the time.

 

Hey Adam.

I found your thread about fixing the clutch switch spring. I'm going to investigate that today. The dash pot is brand new. I attempted to adjust the idle screw with ten and gnd jumped at the diagnostic box and I closed it with no change. I'm thinking I might need to do a full idle adjustment but I've also read that you shouldn't need to play with throttle body settings unless
Someone else already screwed with them :P

 

I'm not clear on what you mean by this. You should be able to adjust the idle with the screw under the drivers side of the TB. If it wont adjust there, I dont see any harm in making a small adjustment with the idle screw on top. Checking your clutch switch is a good idea.

 

From what I understand, to adjust idle you're supposed to jumper ten and gnd at the diagnostic box and set idle to 750 using the adjustment screw below the compression elbow on the throttle body. When I adjusted it, it went about a half turn in with no change in idle. Maybe the idle screw on top was fiddled with and will not allow me enough adjustment below?

EDIT: Was reading the FSM, found the step where it says I'm allowed to fiddle with the TAS screw [Throttle adjustment screw] :P [page F-16 to F-17 for idle adjustment]. I'll be playing with it all this morning. I'll update with any findings.

 

If your car has cruise control, make sure the cable isn't binding or adjusted too short so that it prevents the engine from idling down fully.

 

I fixed it

I checked the clutch switch and it operates as intended with full extension and reads open when depressed.

The fix was as simple as it should be. ADJUSTING THE IDLE. I noticed the TAS had been adjusted as the factory paint marks were not lined up. I loosened the 8mm nut and as I loosened the TAS I could visually see how much it closed the primary throttle plate. After setting that to its most closed position, I jumpers ten and gnd at the diagnostic box and opened the idle air screw about a 1/4 turn before I pulled the jumper and it sat at 750rpm. It's been PERFECT ever since.

It's great when things are just that simple isn't it?

Matt

 

Nice work.

 

Props to you for reading the service manual and following procedures

 

Glad you fixed it. There are way too many little frustrating issues these cars have.