devius

anybody have this problem before? i idle at about 1000rpms but if i even slightly push the clutch, it'll go up to about 1500rpms. any ideas on how to fix this? i know i have a bad clutch but i dont think it would effect idle. maybe bac? tps has been set at with mulitmeter, and tested full range of tps and it returned to 1kohms each time. please help its been bothering the hell out of me

1987RX7guy

iTrader: (3)

you need to re-adjust your TPS I did recently and it fixed it.

SmokinJoe

I've got the same problem, how do you adjust your tps?

J-Rat

iTrader: (2)

http://home.rmci.net/panther/tps.htm

Thats the easy one. Here is another good article for the TII.

http://www.teamfc3s.org/info/articles/idle.html

kristopher_d

Get your clutch hydraulics fixed. I thought it was a minor irritation until the clutch pedal stuck the floor at a stop light and I had to call AAA. $530 later (let the dealer replace both cylinders and the hose, I had to have it driveable by the time I got off work) shifting is smoother and easier than ever.

YakATK

Mine also does that as well....but only sometimes, not all the time. Does it only once engine is warm and even once warm it does not always happen. Any idea on how much it costs to get the clutch hydraulics fixed? Or should I try adjusting the TPS first and see if it still does it?

bingoboy

hmmmmm 530 bucks that's ludicrous. I changed my own for about 150, clutch master, slave and braided ss clutch hose. Shoulda had the car towed home and hit up a parts store, had a buddy pick you up or something...charging 530 bucks for that is a crime. I learned not to go to a shop long ago when I blew my heater hose and Midas fixed it for the low low cost of 250 bucks for a 35 dollar hose. The clutch change didn't take me that long either. If it happens again fix it yourself, you'll be glad you did . If you know what to do you can drive it in the clutch stuck situation too...I drove mine home and fixed it later.

Oh, and I wouldn't think that the clutch hydraulics would mess with his idle. The clutch hydraulics aren't sucking the power of the engine from anywhere (power assist i mean like steering and such). The most you might have is the added spinning inertia of the clutch stuff spinning with the flywheel when the car is in neutral (does that make any sense?)

rx7style

iTrader: (1)

I have that issue as well, but the RPM's only climb 50-150 when the clutch is in. It has nothing to do with the TPS as I've adjusted that many times. My car idles nicely between 750-850 however, so you may have a different problem than I.

kristopher_d

I prefer to do my work myself, and I will be adding spare parts to my collection for future events. It was just one of those gotta have it done right now situations. I'm trying to avoid the same thing with my brakes right now. Got a draging front caliper, but the five-lug kit is sitting in my living room waiting for the last little parts to show up.

drago86

If the idle onlt goes up a little, it could be the friction from spining the tranny when its in neutral. If its excessive it could possibly be the bearings going out in the tranny causing to much drag

devius

would replacing the clutch take care of this problem? or is it something other than the clutch causing it?

kristopher_d

Sorry, I understood your problem backwards. It probably isn't your clutch at all. You may be getting excess drag from worn tranny parts, but it's pretty difficult to diagnose "idle goes up when clutch is pressed." Best bet to start with, change the transmission oil. Is the problem more or less pronounced after driving a few miles (warming up the transmission should decrease the load on the engine).

devius

nope...stays the same through out. goes to 1500rpms no matter if car is cold warm or hot. stupid clutch lol. anybody solve the problem before?

chrisrx7101

When I push the clutch in my revs go up every so slighty... after I have driven for about a minute or so I don't see the problem at all, wonder if I should even be concerned since it is'nt a problem after driving on the road for a bit.

Chris

drago86

that just sounds like the oil in your tranny warming up and becoming less viscus chris, i wouldnt worry to much about it. Mine, even after warming it up does a little, of course i can hear my trany spinning in neutral cus the bearings are pretty bad. Devius, that your describing is either a really bad transmission ( does it make any moise in neutral?) or somethings messed up with the idle paramiters, try checking your tps and such, other than that, im not sure because i dont exactly know what the clutch switch does...

HAILERS

drago86 has a good point. Every manual transmission car I have owned, I have always pushed the clutch in prior to starting. It's become a habit from owning some cars with *bad* starters. There's less load on the engine if your not trying to turn a lot of transmission gears around in cold transmission oil. Its really thick stuff when cold.

That said, you say you have the same problem with a hot car. So why not try this. Disconnect you clutch switches and try again and see if you have the same problem. If not, then its a input to the ECU from you clutch switch that is causing the difference in idle.

Be sure to reattach your clutch switches when thru and before driving.

Oooops. Forgot. You should have two clutch switches. One if disconnected will prevent the car from starting. Thats not the one to disconnect. Its the other. I forget this moment which is which. One is at the top of the pedal, the other lower on the pedal. Only two switches so you should be able to figure which is which pronto.

SonicRaT

iTrader: (6)

Hey hailers, I've got an 89 GXL that does this same damn thing, except it used to be an automatic before hand. It'll idle around 750-800rpm but when I hit the clutch it creaps on up to about 1200 or so, let it out and it comes back down to 750. I know you're the wiring diagram madman of the forum, got any pictures of the switches you're talking about. (And most importantly, would the neutral switch have anything to do with this?)

HAILERS

I've got the pictures.......but this site is disfunctional today. I tried four times to send the jpg and the site falls on its face. The clutch switch is the first one up from the pedal, then there is a second one at the top. That one is the interlock switch. It just controls whether the starter works or not. The lower is the one that sends the ECU a signal that your clutch is in or out.

The neutral switch is on the right side of the transmission and the over the top(fifth) switch is on the left side of the transimssion.

Maybe late tonite I'll jpg the pictures. They are in the Fuel and the starter section of the manual at http://www.iluvmyrx7.com

When in neutral, the neutral switch sends nothing to the ECU. When its pushed in, it sends a ground signal to the ECU.

When the clutch switch is pushed in, it sends a 12v signal to the ECU. When its released, it sends squat to the ECU.

The clutch switch also acts in relation to the cruise control. thru the same switch. But that 12v goes to the cruise control box .

On my n/a I have the interlock sw jumpered so I can start the car without depressing the clutch, and I have the clutch sw thrown as far as I could throw it into the street when it broke apart on me four or five years ago. Left the connector dangling there. I turn my cruise control off by stepping on the brake pedal and have no clutch input to my ECU.

SonicRaT

iTrader: (6)

Thanks for the info Hailers, I'm taking it you have no problems like this? Any idea what the +12V clutch signal does @ the ECU? I'm figuring it's a BAC & TPS issue because I've surely been having problems with those. Another question, what suggested watt led's do you recommend for the TPS adjustment? I don't want to go frying the ECU using too demanding of leds.

BlackRx7

Okay I have also noticed this when the clutch is pushed in but not very much, I've also notice after I get off the freeway or go done doing some high RPM runs and I pull up to a stop light my idle is a bit higher than usual maybe like 100-200 rpms but when I push the clutch in AND put it in first gear my rpms drop to a steady 750 and will stay there after I put it back in neutral and let the clutch out. Pretty mind boggling huh, this come to almost 2nd nature to me cause I did it every day when I drove my car.....

BlackRx7

double post, damn Forum!

devius

SOLVED!!! thank god.

well not entirely but almost there....looks like i have pinpointed it to the clutch switch. when i engage the clutch with my hand, but keep the switch down. idle stays perfect. but moment i release the switch...there goes the idle. so i have it held down with some electrical tape and i hope that a replacement switch will solve the problem entirely. now just gotta get rid of my looping(pulsating) idle

SonicRaT

iTrader: (6)

Damn, does anyone know what that switch does, or what it controls?

devius

it sends a signal to the ecu letting it know that the clutch is engaged. i think my bac is out of whack, because the bac is suppose to compensate for load on the motor, which i believe an engaged clutch would cause the bac to up the idle a lil. but not that much. so i think thats what it was....gotta clean out my bac and see if its opening and closing properly

HAILERS

Devious......I must have missed something there. It sounds to me like the clutch switch is indeed working. When the switch is making (clutch pedal pushed in) it sends a 12v signal to the ECU. Something happens in the ECU when it gets that 12v signal. I *think* it changes the fuel injection amount and maybe adjusts the bac. So I wouldn't buy another switch. It's working.

I don't have that problem with my 87n/a because the switch was destroyed a couple of years ago. My 87turboii still has it and indeed, when the switch is *made* it sends 12v to the ECU. I have no problems with this car either.