Is this a speed sensor problem?

RStom - Hungary · 6 February 2012

Dear All,

I have a problem, and hope you can give some good advise.

The problem is the following:
After a long drive or a long trackday the speedometer starts to behave strange. It jumps up and down from 0 to the real speed I'm driving with. On the meanwhile the engine can rev only to 7,000 rpm. After I stop and cool down a bit the car (about 30min), everything is fine again.

Do you think that it is the speed sensor failure?? 78420-SL0-505

Thanks in advance
Tamás
http://www.hondapartsunlimited.com/acura/sensor-assy.-speed/78420-sl0-505-acura/

goldNSX · 6 February 2012

Yes, looks like.

pgilliam1 · 6 February 2012

Yes. You can buy them on eBay for about $4 US. You can also turn off the traction control and everything should work normally. They are very easy to replace. Good Luck!

RStom - Hungary · 6 February 2012

pgilliam1 said:
Yes. You can buy them on eBay for about $4 US. You can also turn off the traction control and everything should work normally. They are very easy to replace. Good Luck!

I do drive on trackdays with TCS off, but if the problem starts there is no difference if it is off or on regarding the max rev which is only 7,000rpm and the speedometer is also acting strange. Do I understood something wrong?

A new problem arrised and do not know if there is connection between them:
I start the engine and the red brake lamp in the middle of the dash is on (the one that is on when the handbreak is on)! It is not turning off if I let the handbreak out (release it)! If I start to drive with the car (this red lamp is still on) after about 3-400m the ALB and TCS lamps turnin on as well and there is no ABS and the traction control does not work as well.
The sympthone is just like if you want to diable the TSC and ABS function with the factroy method (pull the heandbreak on and drive some hundrer meters).

What can be the problem?
Do you think it is only the problem of the handbreak signal switch?
Do you think it is the problem of one of the speed sensors at the weels?
Do you think that the 2 problem (1.,is the spedometer behave strange after a long drive and rev only to 7,000rpm 2., the handbrake lamp is on and after 3-400m the ALB and TCS lamps are on as well) is connected?

Thnaks in advace
Bye
Tamás

pgilliam1 · 6 February 2012

Sounds like you may have multiple problems. Start with fixing the handbrake issue. Check the wiring connections and make sure the switch is not sticking (possibly spray some electrical cleaner on it) and the brake handle is going all the way down. The TCS and ABS light coming on together usually indicates a defective wheel speed sensor. When my engine speed sensor (vehicle speed sensor - same thing) went out I had the exact same issues you mentioned: speedo jumping around and limited to 7K rpm, after cool-down everything normal, but when I turned the TCS off my speedo became normal (not exactly sure about the 7K rpm limit - that's when I normally shift). Good Luck!

RStom - Hungary · 7 February 2012

Thanks for the help! :smile:

Regarding the speed sensor, do you think that this one is good?? (as the 1992 NSX is not in the list, only the 1993...do not think that there is a differenece but want to be sure) :
http://www.ebay.com/itm/92-05-Honda...es&fits=Model:NSX&vxp=mtr&hash=item53eb18a1bd

pgilliam1 · 7 February 2012

RStom - Hungary said:
Thanks for the help! :smile:

Regarding the speed sensor, do you think that this one is good?? (as the 1992 NSX is not in the list, only the 1993...do not think that there is a differenece but want to be sure) :
http://www.ebay.com/itm/92-05-Honda...es&fits=Model:NSX&vxp=mtr&hash=item53eb18a1bd

It will work fine. You will notice that yours has a pigtail coming from it and the replacement you listed does not. The connector from the wiring harness fits and is long enough to reach, so there will be no modification needed. I put a little high-temp grease on the shaft connector (gold part in photo) because it turns quickly inside the unit. Good luck!

Mirroredshades · 7 February 2012

I had a speed sensor fail and it didn't act anything like you describe.

Sounds more like a speedometer cable to me. Is it loose? Binding? If it is a mechanical drive system, are the gears stipped?

pgilliam1 · 7 February 2012

Mirroredshades said:
I had a speed sensor fail and it didn't act anything like you describe.

Sounds more like a speedometer cable to me. Is it loose? Binding? If it is a mechanical drive system, are the gears stipped?

When the engine cools down the problem goes away. Probably not cable or gear related. Mine did the same thing. What "speed sensor" went out on yours?

RStom - Hungary · 8 February 2012

Thanks a lot! I will do this first...and let you know the result

pgilliam1 · 8 February 2012

Did you fix the handbrake issue?

RStom - Hungary · 8 February 2012

pgilliam1 said:
Did you fix the handbrake issue?

Not yet :-( It is 20+ cm snow out here and the car is sleeping in the garage under the cover

I will try at the weekend....

Mirroredshades · 8 February 2012

pgilliam1 said:
When the engine cools down the problem goes away. Probably not cable or gear related. Mine did the same thing. What "speed sensor" went out on yours?

Driver's side, rear. When you first pull out of the diveway, it would put the car into a jerky limp mode for about 20 seconds and then it would shut off the traction control system. Then the car would operate like normal.

pgilliam1 · 8 February 2012

Mirroredshades said:
Driver's side, rear. When you first pull out of the diveway, it would put the car into a jerky limp mode for about 20 seconds and then it would shut off the traction control system. Then the car would operate like normal.

Was it a bad "wheel speed sensor" or an "engine speed sensor"? Sounds like yours was a wheel speed sensor, completely different units.

Is this a speed sensor problem?

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