speed control sensor (reed switch)

[rrats]

okay... i've diagnosed my problem... my speed control sensor, aka reed switch, is going bad...

symptoms:

1. stalls at stoplights/with clutch pushed in too long (worse in summer when hot)
2. spedometer needle "wiggles"
3. cruise control surges because it can't read a constant speed
4. it's not the ISC, i have not experienced any other stalling problems or idle surges

problem:

i go to the parts store, they look in their database and in the parts book, there is no speed control sensor listed for a manual transmission dsm

does anyone happen to know the manufacturer part number? or have more information on where to get it? i'm trying to avoid the dealership (at all costs) if possible...

i am unable to dissemble my car until i have the replacement part as it is my daily driver and i work daily

thanks for your time!

 

[gringoloco]

1. stalls at stoplights/with clutch pushed in too long (worse in summer when hot)
2. spedometer needle "wiggles"
3. cruise control surges because it can't read a constant speed
4. it's not the ISC, i have not experienced any other stalling problems or idle surges

1. your first problem sounds like your BISS screw need adjusting, throttle body needs cleaning, check idle surge guidelines they apply in your case. I had the same problem with my a/c on in the summertime it died everytime i held the clutch in too long. fix was adjusting the biss screw.
2. speedometer wiggles, sounds like the speedometer cable to me. mine wiggled right before it stopped working. took apart the dash and unscrew the cable from the tranny and tested it out sure enough the cable was broke. so i put in another one and it still wiggled so i adjusted the tightness of the line so they is no play in it and problem solved no wiggle.
3. cruise controls surges again the speedometer cable is probably on its way out.

I have never seen a reed sensor go bad on a 1g because its cable control speedometer, the 2g go bad and cause problems because they are electronically controlled. you can find the reed sensor on a pinout of a 1g ecu off the vfaq but i really dont think that is your problem, i think you should replace your speedometer cable.

 

[rrats]

i can't find the web page, but i had found one off the vfaq that listed the exact symptoms i have, and pointed to the reed switch... however, there is a chance it could be the cable... i am going to get both used...

will a 92 spedometer cable fit in a 90??

the other thing that leads me to believe it is maybe the sensor is that when it's really cold outside, there is a weird scraping noise that i couldn't place the sound, but now that i've read more up on how the spedometer works, it sounds like a magnet piece hitting something not magnet like... could still be a broken cable...

the reason i'm 99% sure it is not the biss screw is that the stalling i'm experiencing was listed as a symptom of the sensor... what happens is that the sensor isn't functioning properly and the car drops to 750 rpms when the clutch is pushed in, and it stalls because the car can't keep up with that kind of change... and i've witnessed that exact happening... however, it has not done it since it got cold outside... i'm sure it will do it some more when it gets warm...

 

[gringoloco]

I bought mine for my 90 gst at advance autoparts its only $30 for the speedometer cable, that you should get a new one so you wont have to replace it again for another 7 or 8 years.

the reason i'm 99% sure it is not the biss screw is that the stalling i'm experiencing was listed as a symptom of the sensor... what happens is that the sensor isn't functioning properly and the car drops to 750 rpms when the clutch is pushed in, and it stalls because the car can't keep up with that kind of change... and i've witnessed that exact happening... however, it has not done it since it got cold outside... i'm sure it will do it some more when it gets warm...

The rpms not holding up though is something with the idle process (ie throttle body, ISC, BISS screw, etc. one of those is causing the stalling problem. It has nothing to do with the reed switch all that does is control fuel cut when you hit a certain speed (the famous speedcut aka reed switch). I know this because ive taken a 1g over the factory speed cut by splicing into this switch off the ecu with the apexi rev/speed meter, it disabled speed cut allowing the car to go to 151 mph, then the stock 5 gear starts giving out so you have to upgrade to a better gear (for ratio, etc). but again the (reed switch/speed sensor)it wont cause any bad idle so forth in a 1g T/E/L. Just replace your speedometer cable and play with the BISS screw and your problems will be solved just make sure to ground it first before adjusting the screw or else it wont take effect if you change anyting rpm idle it will adjust itself back.

 

[rrats]

finally i had more time to relocate the vfaq i was looking through... here's the link:

http://www.dsm.org/archives/1996/08/19960815.txt/30.html

granted it is for the vr-4, however, the EXACT symptoms are what i'm experiencing...

this is why i'm 99% sure that it is NOT the biss screw i don't ever experience any other idle issues, ever

thanks for all the help, i'll look into the new spedometer cable