I've read tons of posts of how to fix this problem but the symptoms seem to be a little different than mine. I have a 96 civic dx hatchback with a d16y8 swap. (I have an SI cluster) Had a CEL for TPS and since have gotten the TPS replaced. For a while my speedo has had a problem. When i first start driving the speedo works fine for about a couple mins... then after a while it starts to get erratic and jump up and down around where my speed is.... then eventually it pretty much only works if I have my foot off of the gas or if I'm at FULL throttle. I will be replacing my VSS just to see if that is the issue but I just wanted someone to confirm what I'm doing before I drop the 80 bucks on a VSS.

I have also read about re soldering the points in the back of the speedo and it fixes problems for some people... but I don't have an iron nor would I know how to do this... I have checked my harness and all the connections to the back of the gauge cluster for anything wrong as well as corrosion.

Another weird thing about other people's symptoms compared to mine is my tach works fine all the time... most of the time other OP's tachs will not work at the same time as the speedo.

Thanks in advance HT!
John

 

I think I've had this before and it was the VSS I believe. Too bad you don't have another one you can just swap in and find out. I would check the connector at the VSS before spending the money. I think coolant was leaking on mine and it didn't have a good seal or something like that. Take the VSS out and clean it and the connector real good with electrical cleaner spray. Make sure noting is corroded. Good luck.

 

My guess is the vss plug is corroded or the wires are breaking. This happens cause coolant,oil,water sit on top of the vss plug. So before spending money on a cluster I would check the vss plug. All so make sure it's plugged in all the way.

 

Thanks for the input, I'll take a look at the connection before I do anything. I already took the old vss out and it didn't look like there was much corrosion or anything at all. I'll check the wiring also. The y8 swap was done before I got the car and the wiring is kinda meh.

Thanks again.

 

I'm pretty sure you can test the VSS with a voltmeter too before you go and spend $$ on another one. Just Google it. If you can't find anything on it, I'll open up my manual and post the info. Sounds like it may be a wiring issue though from what you are saying.

 

So, I ended up cleaning my plug and the old VSS and went to reinstall the old VSS and broke the tab (lol) so I installed the new one I bought and it didn't fix the problem. Is there any possibility that my TPS calibration being off can cause this problem?

I have a mechanic friend that told me that it could be my dizzy also... but I don't have any CEL codes at the moment.

I think I might buy a soldering iron and re-solder the points in the back of my cluster to see if that helps... I don't know yet... but a speedo is pretty important.

 

Sorry to bump my thread again. I just noticed while I was driving it at night the other night... for the first 2 mins or so the speedo works fine like I said... then eventually it gets worse and starts bouncing around the speed I'm at... then eventually it will drop to 0 sometimes... and when it drops all the way down my headlights flicker a little... like they get dim and then bright 2 or 3 times... but only when my speed drops to 0. Has anyone seen this happen? or is this a normal thing to happen when the speedo does that?

Thanks

 

Alternator and/or battery. Get them both checked out.

 

Things I've done so far:

1. Replaced VSS
2. re-solder the joints on the back of the cluster
3. Tried my si cluster in a friends civic and it worked fine(so it's not the cluster)
4. replaced the alternator and speed sensor fuse

Now the last thing I gotta do is the alternator... that is probably the cause of my problem.

 

a volt meter to the battery and see what the voltage is at the battery when the problem happens. If it's around 14v your alternator is OK. I would check the pins on the harness side of the vss or check continuity between the vss harness clip and gauge cluster. Sounds like corrosion issue. Also possible that there is a bad ground somewhere.

 

So i replaced the alternator and when I went to check the voltage on the battery with my multi meter it was only 12.4 like my alternator wasn't doing a damn thing, it eventually drops under 12 to about 11.8 and I just stopped trying. I went for a small drive to see if my speedo was working and it wasn't, then I got a CEL for the VSS... which wasn't there before the new alternator... I'm kinda frustrated so I stopped working on it for the night... but would you mind telling me how I check continuity on the harness side of the vss and as well as between the vss and the harness clip? I tried to check continuity on the fuse 15 location on the fuse box but I don't think you can do that and I'm kinda new to the whole continuity and voltage thing...

Thanks man

 

Also, if the alternator was bad out of the box, would it be causing that CEL?... It seems weird that all of a sudden I'm not getting a charge at all. I made sure to plug back in all the wires on the harness that I had to undo to change the damn thing... and I don't think any of the plugs are interchangeable so I don't think I plugged in a plug to the wrong thing.

 

You can check voltage at the alternator to see if it is putting out anything while running. To check continuity you put the volt meter on ohms and place one lead on the end of a wire and the other lead at the other end of the same wire. The volt meter will either sound a tone or beeb and show 0.1-0.4 ohms if continuity is good. If you are getting good voltage output at the alternator, then the alternator is good and the voltage is not getting to the battery to charge it properly. It's always possible that you got a bad part right out of the box too. If you can get the car to a parts store, they should be able to check the starting and charging system for you.

 

I did check the voltage of the alternator, that's how I knew it wasn't putting out a charge. as for the vss plug, that's what I don't know how to check.. I know there the plug is... and where the vss is... but I don't know where the plug ends to check continuity.

Also, the way I got the car... there is 2 "ground" (i think) that seems like it was added, one from the negative battery terminal to the chassis where the strut bolts... and another from the intake manifold to the driver side strut bolts... I looked at a diagram to check my grounds and I didn't see those 2. I know the negative cable is grounded to the chassis... it has that as well as the other... could the extra grounds be messing something up?

I checked the fuse 15 and the fuse isn't blown and I checked my fuse 41, the 80 amp for the battery and it's not blown... btw

 

An extra ground won't hurt anything but s ground that isn't in the correct place could. As far as checking continuity on the vss circuit you have to get a wiring diagram and see which pins on the gauge cluster harness are for the vss. Then put your multi meter on ohms. Put one test lead at the correct pin in the vss clip and there other lead in the pin that is for that same wire on the gauge cluster harness. I'll see if I can find pin locations for you when I go to work. You will either get a good continuity reading of between 0.1-0.4 or a reading of ol which is a broken or corroded wire. I would fix your alternator problem before pursuing this tho.

 

I'm going to replace the alternator again... I'm thinking that the VSS problem is all a cause of my alternator... before when I had the old alternator (the whole reason I'm changing it in the first place) was because my speedo was jumping... i read that fuse 15 is a leading cause and that was fine so the last thing on my list was the alternator... now that's new and its not working at all as well as the alternator not charging... then I get the code for the VSS... this could all be coming from just a bunk alternator out of the box. I hope i'm right... I read that a bad alternator that isn't working 100% can cause all kinds of CEL's and problems in civics...

here's to hoping! and thanks for your info man!

 

Alright update....

I replaced the alternator with another new one from kragen... and now my voltage with the car running is 14.2~ which is pretty much normal... so my battery is charging now. BUT, now my battery light is on and my VSS still isn't working... could my battery have been bad as well but now its presenting itself because I have a good working alternator???

Could a bad battery be the cause of my VSS not working just like the alternator could have caused it???? I don't even know any more xD

 

I tested the harness side of the VSS plug by using my test leads on the thermostat housing... the black ground wire on the plug DOES have continuity, the yellow/white wire with the key on is putting out 4.8v and the yellow/blue wire is putting out 0.7v I think that's low... but I don't know what to do from here.... any ideas?

 

I can't figure out the problem... it's probably the plug but I did find 2 wires... one is a huge connector that isn't connected to anything and the other looks like a 2 pin connector that was intentionally taped off... don't know if that can cause any problems but this is the first I've seen it...

 

Swapped the VSS just for ***** and giggles to one that I had laying around and it didn't change anything... it's probably the plug or harness somewhere near where I was working on the alternator. both the ECU and the speedo aren't reading the VSS so it must be somewhere close to the plug... Hope I can find the problem soon.

 

I guess that picture on the bottom is normal that its not connected to something... just from looking at a wiring harness in a picture.

are the harnesses from the 96-98 y8 the same as the harness from the 99-00? I'm not sure what year my motor is from and I'm just thinking about replacing the whole harness because this wiring is so **** and I want to make sure this doesn't happen again....

 

Actually, don't I have to find out if my ECU is obd2a or obd2b and that will let me know which harness I should buy to match that?... I noticed from pictures that the one difference(that I notice) is that the ob2a harness has an extra ECU connector.

I'm just worried that when I replace the harness that I'll have to get a new alternator again... because maybe the alternator plug will be different since the auto parts store had 2 different ones with different connectors.

 

this is what you'd usually be looking for

 

Did you get the alternator to charge the battery or are you still having a charging issue as well?

 

My battery is reading 14.2~ with the car running, but I still have a batter light... its odd