Speedometer Playing Hop Scotch

ECU, Wiring, Sensors
 Reply
User avatar

Speedometer Playing Hop Scotch

By BaTzEG92
- Fri Nov 20, 2009 3:10 am #157420 Hello all!

On my drive home from work tonight, I had just exited the Turnpike and was waiting a traffic light. Light turns green, go through first, second, third, and figure I'm doing about 35mph when I look down and notice my speedo hanging out at 15mph. So I continue glancing at it, watching it bounce from 0-40 all on its own, but mostly bouncing from 10-25mph while I'm low in 4th.

I checked another post on here (cluster on the frits) but he was concerned with a cluster he'd just received so I figured I had something different going on.

Up until I slowed to a stop at the "offending" traffic light, it was working fine, so it was very sudden. I have not since started it and went for a cruise, so I don't know if it will come and go but this is something I'd like to know is fixed sooner rather than later.

Any ideas where to start troubleshooting? This is my DD so I can't tear her apart and leave it sitting for a few days. Thankfully Thanksgiving break is coming up but that's about the only free time I'll have til the end of the semester.

I appreciate any and all feedback, thank you guys!
User avatar

By JUICE
- Fri Nov 20, 2009 3:54 am #157424 most likely either your VSS (vehicle speed sensor) or your cluster. both are a easy fix. no "tear down and sit a couple days" :D
User avatar

By BaTzEG92
- Fri Nov 20, 2009 4:15 am #157427 Hey alldatJUICE,

Thanks for the reply :D.

As far as troubleshooting those two, does the troubleshooting go kinda like this: "Replace VSS. Still broken? Replace cluster. Still broken? Try again"? If so, which would you start with? Plus, doesn't cluster replacement involve ripping the dash apart? The only dash cluster I've worked on was on a buddy's 2001 Tiburon, and we had to pretty much gut the car to do it haha.
User avatar

By mooze
- Fri Nov 20, 2009 4:22 am #157430 make sure wires leading from vss are not cut or anything. that will cause it 2
User avatar

By itCouldgeTwoRse
- Fri Nov 20, 2009 5:34 am #157446 to take the cluster out its i think 2 screws on the plastic infront of the cluster then that whole peice with the vents pops out make but b4 you pop that out pop out the yeild light button and disconnect that. then once thats off theres 4 screw that hold the cluster in. pull it out enough to get your hand behind it and i think theres 3 or 4 plugs in the back of it.


as far as the vss goes i think theres a plug connector on it and its 2 10mm bolts that hold it in. and if im thinkin right its kinda behind the starter but you can get to it without crawling under your car.

i have the same problem kinda sept my speedo is 10mph off :?
so i just roll with it :lol:

By danomatic93
- Fri Nov 20, 2009 6:44 am #157469 If CEL is on, check the CEL FIRST!!

If the CEL pertains to the speedo sensor, ding ding ding, it's probably just the sensor located ontop of the transmission.

If CEL is NOT on....
Problem: The speedo doesn't work but the odometer works.
Solution: Replace the cluster or just replace the speedo gauge

Problem: The speedo doesn't work AND the odometer doesn't work.
Solution 1*: Bad Sensor - Replace the speedo sensor in the transmission.
*CEL should be on
Solution 2: Bad Gauge - Replace cluster or just replace the speedo gauge
IF Neither solution above fixed it.
Solution 3: Check all wiring from the sensor to the gauge. Because the signal is disrupted somewhere.
User avatar

By BaTzEG92
- Fri Nov 20, 2009 4:21 pm #157500 The CEL actually popped on this morning on my way to school, so once I get home from work tonight (school then work, ahh college) I'll try giving it a look, or tomorrow afternoon.

Just to double check that I'm reading the DIY correctly, to check ECU codes:

Take a piece of thin wire, strip both ends, connect one end of wire to one of the ECU plug connectors and the other end of the wire to the other connector. Turn ignition to On (not Start) and watch CEL blink for codes, then go from there based on codes.

How could my alternator affect the speedo?

And itCouldGetWorse, is it 10mph over or under? :D and hey, it still works. Mine worked on the drive to school, yet the CEL went today haha and last night I had no speedo AND no CEL :lol:
User avatar

By chnzgoofball
- Fri Nov 20, 2009 4:52 pm #157504 yeah i had the same issue with my speed sensor, i just popped in a new one and viola it was back to normal

By danomatic93
- Fri Nov 20, 2009 5:06 pm #157507 At high mileage the cluster, at least the speedometer, starts to flake out. This is not always true but I my 180k speedo pooped on me years back. A bad VSS will cause a CEL so I'm quite confident that it's not your VSS.
User avatar

By itCouldgeTwoRse
- Fri Nov 20, 2009 7:28 pm #157529 its 10 miles over. so on the highway my gf thinks im going to fast and shits bricks :hehe:
User avatar

By Benj
- Fri Nov 20, 2009 10:26 pm #157599 ok well in october just before i sold my car my cluster did the same thing and then the belt squealed like a sob, so i turn the car off fix the belt go to start the car click click click, so i bomb started the car and bamm it didnt do it again and as far as i know it still has not done it... there was no battery light as the alt was still putting a lil bit out every now and then and there was also no cel light.

so 1 check your alt to see if the belt is lose
User avatar

By BaTzEG92
- Sat Nov 21, 2009 7:46 pm #157716 @ilmcrx - Gotcha, I'll keep that in mind. As of now though, the rest of the cluster is working alright and my belt is quiet. Cross fingers.

@itCouldgeTwoRse - Haha, very nice, keeps her on the edge of her seat, eh?

@danomatic93 - I did indeed throw a CEL, but so far it goes away each time I turn off the ignition. It turned on yesterday morning on my drive to school, was off for two trips, then turned on yesterday evening on a short drive to a restaurant. This morning I drove ~12 miles round trip to karate and it didn't come on.

I think I might buy a new VSS as a first troubleshooting step; does this look alright? It's a fraction of the OEM price, but they have excellent feedback. In the mean time, if the CEL comes on again, is this the plug I'm looking for:

Image

And are the steps I listed above the correct way of checking the code?

Thanks again for all your input, guys, I appreciate it :thumb:
User avatar

By BaTzEG92
- Tue Dec 01, 2009 6:32 pm #159371 As an update, I bought the VSS I linked in my last post and installed it. My old VSS had a trio of zip-ties securing the harness to the sensor, so I snipped the ties, replaced the sensor, and it worked fine during a test drive (last Friday).

Yesterday, however, it spazzed once, then just settled at zero and my CEL came on while driving. I plan on checking the harness connector (maybe it was ziptied for a reason, although the clip on the harness seemed secure to me). When I turn the car off, then turn the ignition back to Position II, the CEL goes off after 2 seconds; it doesn't turn back on until I've driven for ~10 minutes.

If I hook a paperclip into the CEL plug on the ECU, can I leave it there while I drive and then check the code once the CEL clicks on? Or is this unsafe/will fry my ECU?

Speedo

By gtstwincam
- Thu Dec 03, 2009 9:42 am #159741 I have the same problem with my 95 vx. Speedo works only in the early morning when cold but malfunctions when the engine warms up. I get an intermittent CEL 17. I replaced the VSS, changed the VSS harness plug end, the speedo head twice and the entire cluster assy twice... Still the problem exists. I inspected the wiring harness and found no open wirings or shorts.. No wiring rubbing on intake manifolds or anything..

Im out of ideas.
 Reply
Return to Chassis - Electrical