My speedometer stopped working yesterday. Trying not to take it to the dealer if I don't have to. All remaining instrument gauges work properly. I own a Haynes but no Helms! Found that one fuse #15 was bad, but replacing it didn't fix it. I plugged in my new Power FC to make sure it wasn't an ECU problem. Still nothing! Went for a drive and the FC showed only a 33.3% inj. duty cycle at WOT. I read that he speed sensor affects injector duty. Could this be the problem? Any other suggestions greatly appreciated.

 

I once had a bad speedo-cable in my '86 lude. If you have a defective speedometer cable, it'll not show anything. Have you checked your speedo-cable?

p.s. Payment for s2k antenna is going out today via paypal.com.

 

I had this problem recently with my EF... Alternator was putting out enough power, but not regulating it correctly, so my battery was dying... I replaced the alternator and all done. When the power was low, the speedo would not even work!

I'd check the battery and alternator, at least to rule them out... Are all your other fuses ok?

 

Check the speed sensor plug. 9 times out of ten when a honda speedo stops workings it's that.

 

The fuse I replaced was for the alternator / speed sensor. That didn't fix it! Since the FC only showed the injectors at 33.3% duty cycle at WOT, I'm thinking it is the speed sensor as well. I'll hopefully use check that out tonight! Thanks for the help guys.

 

do you have a test pipe or did you adjust or mess around with the O2 sensors at all? If so, they may be shorting out (the o2 heating system) and causing you to blow fuses, expecially the speed sensor/altenator fuse. Check all your fuses again. All else I can think of is if you got any fluid in the speed sensor plug, I got some coolant in mine when I was swapping intake manifolds, some coolant spilled and got in there. I dried it out with a leaf blower, good as new.

 

Actually....it stopped working after I extended my O2 sensors and took my test-pipe off this weekend. Sounds like I need to check all my fuses! Thanks for the tip.

 

that's definately it then, you must have a short somewhere, a part of the wires touching each other or a part of the car. Fully insulate them. For some reason, the O2 heating system is in the same circuit as the altenator/speed sensor, really wierd. It took me awhile to figure that out. Battery will die if you don't fix it asap.

 

Rstor,

Is your speedo jumping all over the place? I am experiencing this at the current time. In addition my car is idling at 1100 rpm while making a faint back fire sound. I believe i am throwing a code 20 and 65....20 being like sensor failure and 65 deaing with secondary o2.

vaporsi,

is the speed sensor the black plug on the tranny....located towards the back of the firewall. I recently changed my clutch...wondering if i had damaged it??

 

vaporsi~

Sure enough...when I got home from work, #15 fuse (altenator/speed sensor) was blown again! That was what I replaced last night. Now, help me figure out what I need to do exactly. I used shrink covers on most of the solder points, but a few were too big for the cover sizes I had. Don't think I taped them individually! Could they be touching each other? Secondly, I had to zip-tie the extra wire to the shift-linkage to keep it form hanging too low. It couldn't be grounding out there could it? It is stealthed and the bundle is taped completely. Please help so I can crawl under the car tonight. Thanks!

 

vaporsi~

on me when we meet! Re-taped each wire individually and the speedo works again. Great call!

 

aww, sweet Rstor! I used butt connectors instead of doing it the right way (soldering). The butt connectors were easier than lying on my back with a soldering gun. Props on doing that! I found out using a test pipe was more heache than having a cat. It was manly fitment issues, I had to remove the heat shield. I just ended up plugging up the hole in the test pipe for the O2 by using a oil drain plug for a chevy (I think) and cutting the wires off and sealing them up. I got a check engine light, but lived with that. It's cool though that your problem was fixed. I would try to avoid attachting anything the linkages because they move with the motor and you don't want wires vibratiing or moving too much. That was one reason why I ditched the 2nd O2.

Dragdc2, I'm not exactly sure about the color of the plug, but it sits right on top of the tranny. You should be able to clearly see it when peeking down from top of the engine bay, just below where the intake piping would exit from the throttle body. If that sensor is damaged in any way, the speedo may jump or not function at all, there could also be a loss of VTEC. If any fluid gets into the top of the connector plug to the sensor, the sensor could also fail to work causing a short and maybe some blown fuses. Some coolant happened to get into the plug when I was doing an intake manifold and caused the sensor to be faulty. I had literally pissed on myself in frustration trying to figure out what was wrong. Finally, I took a bottle of water and lightly rid the plug of all green coolant then took a leaf blower to it to dry it up, problem was solved. Maybe you got some tranny fluid in there or on it?

 

how much is a new speed sensor thing? i just got a used tranny put in my car and my speedo is not working...nor the odometer and it throws a CEL and VTEC does not seem to engage.

 

Vaporsi - You said that your check engine light was on for sealing up the hole for the O2. If the check engine light is on, doesn't that put your car is "safe" mode? What did you do to clear the code. I was just wondering...(not knowing a ton about it)...

 

don't worry about the check engine light for the 2nd o2 (failing cat). It does not affect anything other than having that light on. IMO, the check engine light is more like a dummy light when something goes wrong. It's only usefulness is to trouble shoot a possible problem. But I never would've known about the O2 wires and blown fuses through the codes that the check engine gave me. I just guessed it was the wires since that was one of the mods I had last done. Basically, you can open up the dash cluster and unplug that silly orange light. Keep in mind that is terribly illegal, as if using a test pipe in cali isn't. I picked up the plug from an auto-parts store. It took me several trips to find the right size and thread. It just made things simpler as that second o2 sensor was just a pain in the ***, or should I say that my choice of fabricating a test pipe was a pain in the ***, or just the fact that I messed with something gave me more problems. blah!

 

vaporsi~

Soldering wasn't that bad. I removed the entire wire from the car though. I've got the SMSP adj. ITR header, so my O2 wires had already been extended 12" previously. I added 2" extension to my primaries to imporve low-end torque and needed to extend the O2 wires more, now at 16".

I left them zip-tied to linkage for now. They are loosely tied for free movement. Just wanted to eliminate them from catching on anything.

Lastly, I agree about test-pipes being a pain in the ***! With my SMSP adj. 2.5" exhaust, I can readily change out the cat/test-pipe in a matter of minutes literally. I ran my test-pipe for about 2 weeks and couldn't stand it. It makes the car louder and it smells funny! I'm able to eliminate the 2nd O2 now that I have a Power FC, so I'm excited about that. I'll probably remove the O2 I just extended here in the near future and use a screw-in plug to fill the hole.

Thanks again for the help!

 

any of you guys have any idea how difficult it would be to replace a speed sensor? is it just two bolts and you unplug the wiring harness? or is there more to it than that?