Ever since I have owned my FD I have had an issue with the car stalling on deceleration.
This does NOT happen everytime I am braking and downshifting but it does happen often. It also tends to happen more often with the A/C on.
Now, I have gone through several searches on here to try and remedy this problem as it is always fun to have the car stall on a turn and lose Pw steering
I have adjusted my dashpot, it makes perfect contact at 2800RPM
My TPS is giving the proper voltages out of the 3G and 3F connectors
My throttle cable has the perfect 1-3mm of play.
Soooo....
Could my E/L sensor be taking a dump and not letting my stock ECU know that it needs to kick the idle back in?
Do I need to rip my throttle body/ UIM off and take a look at my ISC/IAC valve for carbon build up?

Any expertise would be greatly appreciated
Thanks
Josh

 

I believe there was just a pretty large thread on this topic, try searching for it.
Short answer:A lot of times its the clutch switch, or tuning.

 

Check the clutch switch, 9 out of 10 cars that come into our shop need it replaced.

 

I have checked the clutch switch, It seemed to be working fine but I replaced it with a brand new one from mazda anyway ~2000kms ago. Mako, I have tried several searches, is there a specific thread you remember that I should be looking at?

 

https://www.rx7club.com/showthread.p...ght=car+stalls

https://www.rx7club.com/3rd-generation-specific-1993-2002-16/fixed-my-idle-problems-backfiring-bucking-more-170731/

 

probably the clutch switch, if you have a PFC and the commander you can diagnose it in about fifteen seconds, mine's bad, and it just came in today :woot:

 

the other thing that it could be is the dashpot or your tps could not be set properly.

 

Thanks KKM but as I wrote in the OP my dashpot makes perfect contact at 2800 RPM and comes back in slowly, as the FSM says. I also mentioned that my TPS is set correctly. I do not have a PFC, just stock ECU, I wish I could check it that way. My clutch switch is less than 2000kms old, I just pulled it out and it still looks brand new and does not rattle to indicate a broken spring.

 

Make sure you don't have a vaccum leak. If large enough I've seen this cause the issue. Most commonly seen when someone installs a Greddy Elbow and doesn't properly cap the large line that used to connect to the srear of the stock elbow.

I've seen this on a couple cars.

 

This does sound possible however, my car is completely stock other than an HKS RS intake so all of those hoses are in place.
I have checked the AWS hose as well as the white couplers to the ISC/IAC valve and others to the rear of the extension manifold and throttle body, all in place. The only reason I was guessing the ISC is that from searches I have concluded that it shuttles open at different rates to maintain idle based on signals from the E/L unit, i.e. Headlights and A/C in my scenario?

 

You can check the clutch switch by sticking your head down there, and looking at it. Push the clutch pedal, until it no longer makes contact with the switch plunger, and see how far it pushes out. I believe it should go out about 1", or more. When mine was broken, it didn't rattle or anything, but it only went out about 3/4".

If it is the clutch switch, just replace the spring with a spring from a ball point pen. It works, and the one I used was actually stronger than the stock one, so I think it'll last longer.

 

The clutch switch comes out at least 1'' it is nearly brand new, I replaced it in may of this year. When I replaced it in may the problem still exsisted.

 

sorry, didn't read the full post.

and just cuz your motor is all stock, doesn't mean one of the lines isn't broken, you may as well replace them all with silicone and do the simplification.

and just because we were talking about replacing the clutch switch, I just finished doing mine
didn't feel like playing musical cars to drive it tonight, so tomorrow, first thing I do when I get off work is taking it for a cruise. mine was definitely shot tho.

 

Alright, well I guess I'll order the hose kit from rx7store and plan on the car being down for a bit, guess it can't hurt to rule out a leak.

 

get a block off plate kit too while you're at it and simplify that bitch. I'm non-sequential and I've got I think 7 or 8 vacuum hoses. If you're gonna get a PFC leave it sequential tho.

 

So I thought I would check to make sure no connectors were loose on the passenger side of the car (thinking potentially the clutch switch wasn't plugged into the ECU) and I came across two black of different size and shape not plugged in.
I cannot seem to see where they are supposed to be plugged in, or whether they could even be the culprit since I am not great at reading the wiring diagrams in the FSM.

They are both coming out of the 90 degree elbow near the ECU, this picture shows both, the smaller one is just to the right of the elbow.

 

second picture doesn't work, fyi

 

I edited that picture out* too blurry,

 

You guys are amazing. I've had a similar issue but I've been putting it off to a bad idle tune on my PFC. I noticed this thread and thought "Huh, I'll go check that out." I didn't even know I had a clutch switch. Sure enough, broken. One dismantled ball point pen later and I have a working clutch switch. Took less than a half hour from finding this thread and a working switch. Many thanks,

Dave...

 

how'd you get the switch apart? I can't seem to find the thread for some reason.

 

My switch just had four metal tabs holding the plastic electrical socket to the back. Bend those up, and the innards fall out. It even looks like a ball point pen on the inside. Mine also had some black gunk, probably old grease, covering the contacts. Wiped right off. Even if you have a new switch, it is possible that the spring fell off the post it sits on. Couldn't hurt to check.

 

Ya, just bend the metal tabs back with a flat bladed screwdriver, I did just to double check my springs. I may be on to something with this. With the switch plugged in my car stalls just as often as when the switch is not plugged in. My best guess is that there is no signal being sent to the ECU AT ALL from the clutch switch regardless of its condition, somewhere along the harness the electrical signal is lost?

 

possible, faulty wiring somewhere, do you have access to a multimeter? or if you have a pfc you can check it with the commander

 

I will be checking the switch 'plug' when I get home today
I have also booked the car into my mechanic on tuesday as I think this has quickly exceeded my capabilities.
After I get my suspension sorted out this winter the PFC will be first on my list beleive me!!

 

Oh don't worry, replacing my clutch switch didn't fix my problem, maybe a lose ground, which means lots of fun wiring tracing.