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The lower switch on the clutch pedal is the clutch interlock switch, and only closes the connection when the pedal is down the whole way to allow the starter relay to get power.
The upper switch on the clutch pedal is called the "clutch pedal position switch" for lack of any better term, since it really don't give the position and more than the clutch interlock switch does. However, it is part of the neutral switch circuit. It detects when the pedal is up the whole way (so neither switch can tell if the clutch is partially engaged). If that switch is triggered, the ECU switchs over to the neutral fuel and ignition map, same as if you put the shifter into neutral. So basically, you have a problem with your neutral switch and/or the neutral switch wiring (on top of the transmission, outside the case), where the ECU doesn't know you are in neutral from that sensor, however when you open the circuit by pushing in the clutch pedal, the ECU switches to the correct map from the upper switch triggering there. |
Thank you guys so much!!
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Fazda, I was having this exact same problem, except for the stalling... The plug on my neutral switch had somehow come loose, causing the hunting idle on cold starts. I unplugged the switch, tested it with a multimeter (it worked fine) plugged it back in and the problem disappeared.
Posted From RX8Club.com Android App |
CEL post op?
So should the CEL go off after this is replaced or does one have to disconnect the battery to get the light to turn off? I replaced mine over the weekend, it was throwing the PO850 code, but the CEL remained on afterwards. Just curious and seems like a good conclusion to an excellent thread.
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disconnect battery, or erase the code with whatever reader u have
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Fyi I'm having the same cel 0850 and found out that AutoZone has the switch part# sw5531 for $78 with a lifetime warranty. I'm going to check my connectors first but I'm going to have to probably replace it to pass smog on my New 04 black Roxy 6 speed
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After finally finding the image of that part, I believe it's the one that goes to the clutch pedal not the one on the trans, going to inspect and remove mine today and see if it's operating properly. Would like to know the AutoZone part # for the one on the trans so I could get the lifetime warranty
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Not to blow up this thread... But after getting underneath to inspect mine and to see if the wires would indeed fit inside of a deep 27mm socket, the first thing I noticed was that the wires insulation on both wires was exposed nearly 5mms at the two harness plugs and was touching inside the two wires sheathing that was covering both insulated wires. The external sheath simply slides farther down the wires and I excessively electrical taped over the exposed areas and zippity do daa'd the tape for extra measure... Now off to try to set the cel off again and see if that did the trick.
https://cimg8.ibsrv.net/gimg/www.rx8...484d73c7ab.jpg https://cimg1.ibsrv.net/gimg/www.rx8...bd5929eded.jpg |
Wanted to add that my 05 had the same exact failure as raxtaman8's car. The wire insulation was pulled back a good 1/2" from the connectors and shorted to each other. I took the pins out of the connectors and slid heat shrink over them. Neutral switch is working great again.
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Originally Posted by banzairx
(Post 4771455)
Wanted to add that my 05 had the same exact failure as raxtaman8's car. The wire insulation was pulled back a good 1/2" from the connectors and shorted to each other. I took the pins out of the connectors and slid heat shrink over them. Neutral switch is working great again.
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i have that problem
Originally Posted by zoom44
(Post 2199294)
actually-
in the manual transmission of the rx-8 there is a switch that tells the PCM "im now in neutral" if the switch is stuck or faulty it can cause idle hunting issues as the pcm thinks the car is in gear and doesnt understand what to do with the air info its getting from the MAF so its load calculation gets all messed up |
idle up and down
Originally Posted by FazdaRX_8
(Post 4592105)
I have read through several threads, and looked at the FSM, and napa sites
2004 manual rx8 symptoms cold start, idle surges up and down, if I press in the clutch pedal it idles normal, if I press in the clutch pedal about an inch it goes away. after the car has warmed up when coming to a stop and pressing in the clutch the car dies, I can restart it just fine. I might be crazy but if I rapidly press and depress the clutch, and really put my foot down, it won't die. so looking at the pedal there are two(2) switches, I have read through many threads and there is reference to the "neutral safety/start switch" this is the bottom one. I can find this part. but then there is the upper one. I can't find this part at napa, or autozone. the FSM calls it a "Clutch Pedal Position sensor". but the FSM doesn't have the "neutral safety/start switch". I think the upper one is at fault but then there is the neutral saftey switch on the transmission, and I have seen threads about those causing similar issues. I just wanna know for sure about the 2 clutch pedal sensors/switches. i was having rpm going up and down but when car has been warmed up it idles. after a check up by the mecanic he found that my car does not have a neutral switch it was removed. my car can be started wihout having to press the clutch. so i was wondering if its the removal of switch causing up and downs rpm? can it be bypass or i will have to seach for a swtich??? |
Originally Posted by BBOP
(Post 4943288)
Hello i recently bought an rx8 2005 MT 6spd
i was having rpm going up and down but when car has been warmed up it idles. after a check up by the mecanic he found that my car does not have a neutral switch it was removed. my car can be started wihout having to press the clutch. so i was wondering if its the removal of switch causing up and downs rpm? can it be bypass or i will have to seach for a swtich??? |
the cruise control won’t work either because the equivalent signal that the pcm registers is the same as the transmission being out of gear
just curious though; if the neutral switch is missing, then what’s threaded into the hole where it should be located? https://cimg1.ibsrv.net/gimg/www.rx8...7a87ec5b8.jpeg However, to the best of my knowledge it has nothing to do with starting the car without pushing the clutch in. That involves the clutch pedal position (safety) switch on the clutch pedal assembly. So I’m not sure if the situation might be a lost-in-translation communication issue or if you possibly need a different mechanic. Edit: may be wrong about the clutch switch not affecting the idle situation. Both the neutral and clutch switches wire directly into the pcm and there is likely a control strategy for idle wrt whether the clutch pedal is in or out. . |
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