RotaryPoweredCop

Ive noticed on my SE the idle has always been high. (1700RPM usually) But it ran good and idled very smooth other than being high.

OK so today I decided to adjust the TPS..I couldnt find a junk yard TPS to make a light so I used a voltmeter. Got it adjusted..seemed to be fine. Got in the car, pressed the clutch and the engine jumped up about 500RPM. Let off and then did it again. Same thing..held it down..and it caused the engine to surge and fluctuate between 1500 and 2000 RPM.

Can someone explain this?

Kentetsu

Maybe your throwout bearing is dragging, so when you push the clutch in the drag is relieved and you increase RPMs. Is there any change in noise between clutch in/out?

RotaryPoweredCop

There is a slight rattle type noise, its not bad and only noticable if the hood is up and the door is open. You cant hear it when you are driving

Tony Silva

Ground wires, man!!!!!!!!!! Ground the Engine. RX-7's are notorious for wierd unexplainable idleing problems. On my 85 SE I ran ground wires from each section of the motor: front cover, rotor housing, middle motor, rear rotor housing, and the rear part of the engine...I ran all new ground wires to the car chassis then one fat ground wire from the chassis to the battery. After that, I had no idleing problems whatsoever. Infact, the car actually ran smoother on idle and seemed to accelerate a litle bit faster in the upper (4k-6000) RPM range. It's worth a shot.

Kentetsu

Try putting it in nuetral with the clutch out, then push the clutch in. I believe that the rattling noise is the throwout bearing going bad. As this happens, it will start dragging on the engine.

In my 7 I have the same issue. On some days, when I put it in nuetral, it will actually start easing the car forward just because of the drag.

Anyway, try that and see how bad it really is...

LongDuck

Wait, wait, wait... before you get too far into troubleshooting tranny issues, remember that it ran just fine before you changed the TPS setting.

The TPS tells the ECU where your foot is in the accelerator. The computer uses the AFM signal and the TPS signal to determine where it thinks you want the engine to be revving. In this case, it sounds like your adjustment to the TPS has thrown off what the ECU thinks should be an idle condition.

Start over at the TPS and build a 2-light rig. The voltmeter thing works fine, but takes two voltmeters. The 2-light rig is simple, easy to make, and effective. Search on "2-light" and "TPS" to get the assembly diagram - takes 5 minutes with a soldering iron and you're golden.

Install the 2-light gizmo on the green plug by the AFM, and then, with engine off and keys to 'run' - throttle should be at 'idle' position; see how many lights come on. If both lights are on, you need to adjust until just 1 light is on. If no lights are on, you need to adjust until just 1 light is on.

I've found that the best setting for my car (idle at 800rpm) is with 1 light on, and if you push on the TPS adjusting screw with about 3-5oz of force, the 2nd light will come on. The second light indicates 'off-idle' position, so you want that to be very finely tuned to any input through the throttle linkage.

Returning the throttle linkage to idle should bring only 1 light. Grab the cruise control cable or throttle rod and 'snap' it a few times to make sure it's returning to it's most natural position.

Give that a shot and reply back. There are other adjustments to be made to drop the idle down to 800-900rpm where it should be (when warmed up). HTH,

RotaryPoweredCop

Well...the whole reason I decided to adjust the TPS is that I was gonna remove the Cruise Control. It didnt work anyway. I began loosening the nut that keeps the cable tight and removed the cable. The idle dropped to around 400rpm and began surging.

Thats when i began adjusting the TPS and thats when things went south. Im gonna make the light..problem is I cant seem to find a used TPS at a junkyard to make one. Thankfully I live in AL and cn borrow one from BNR.


And if it is my throwout bearing...how big of a job is that?? And how long do I have before it goes completely?

LongDuck

You don't need a spare TPS to make a 2-light rig; you only need 6 pieces of wire, two light bulbs, and some crimp-on spade connectors.

I may post a tutorial on how to build a 2-light rig later tonight when I get some good pictures - watch for it.

I thought everybody with an SE had already built one...

RotaryPoweredCop

Every post or tutorial I have read has said to use a old TPS connector. But yous guys are the experts.


However, I managed to adjust the cable that controls the cruise control, and took some more tension out of it and it fixed the clutch problem. I dont understand! It increased the idle maybe 300 RPM but it made the surging from the clutch stop.