#1 Speed Sensor Tests OK - Pics

[4wdds]

My speedo on my '97 FZJ80 had been "acting-up" when it was really cold in Feb. . Sometimes bouncing or not working at all untill it warmed up to operating temps . Usually worked fine except for bitter cold cond. .
Finishing up some of the checklist for Moab and speedo quits altogether .
I don't think any of my maintanace is related to killing the speedo . Reinstall rebuilt supercharger, rear axel maintanace , PS pump .

FSM Troubleshoot and search led me to test the #1 Speed Sensor 1st . FSM claims it is number 1 cause of speedo malfunction .


I put the pass. rear on a stand , TC in N , jumper wires from batt. to sensor terminals . + term 1 , - term 2 . , Multimeter /Voltmeter + term 3 , - term2 . Rotating the rear wheel caused the voltage to cycle from 0 to 12 V .

#1 sensor tests OK .

Next I pulled the speedo drive gear .


Everything seemed to be in working order . No wear or slippage of drive gear or shaft .



I reinstalled and moved up to ECU connection test .
I turned ign to on , tranny in N , voltmeter to port per FSM ,rotated rear wheel and voltage did not fluctuate with rotation ......stayed steady at 9.58 V .

What does this mean ?? ....... Bad wiring loom ??

I do have a Superlift speedo correction box installed . I'll be checking that tonight but I am assuming the problem is before the box.

ANY input would be greatly appreciated . X country to Moab with no speedo or cruise would REALLY suck .

Thanks ,

Ron

 

[gotmud]

Check the ground wire that attaches to the rear of the intake. This is the ground for your speedo. Chances are you may have loosened it while doing your PM or it just has a bad connection.

 

[4wdds]

Sweet , I'm on it !
Now that's the type of tip a desperate Mudder needs . Thank You , gotmud
I'll report back .

 

[IdahoDoug]

Obviously one thing to do is do the same test without the correction box on.

DougM

 

[4wdds]

Are you talking about the one on the back drivers side of the Intake Manifold ? If so , that connection feels solid as a rock .
I stuck a mirror back there and what I could see looked good . No cracks or anything .
It is a pretty heavily protected bundle that dives into a much bigger harness along side the block .
Is there anyway to test this ??

Thanks again for any help anyone can provide .

 

[CJF]

I thought it was common MUD knowledge that a bouncing/misbehaving speedo in very cold conditions was usually due to the cable being old/worn and binding.

No? Or only on earlier years?

Curtis

 

[gotmud]

His 97 doesn't have a cable. AFAIK 93+ have a VSS that sends a signal vs. a traditional cable setup.

 

[CJF]

His 97 doesn't have a cable. AFAIK 93+ have a VSS that sends a signal vs. a traditional cable setup.

Ah. Figured it must be something like that.

Thanks!

 

[4wdds]

After staying up late wiggling every wire in the truck , I come home from work and go to move my truck........Speedo works !
It is also a beautiful day here . Above 50 for a change.
Looks like I'm searching for a short .
Clueless in that department . A corroded wire not attached to anything is about the extent of my diagnostic abilities .

With any luck I can get out west and back before I lose the contact again . If anyone sees a white 80 along interstate 80 with someone swinging from the wiring harness........you can update this thread that I am still "working" on the speedo problem

 

[4wdds]

[/IdahoDougObviously one thing to do is do the same test without the correction box on.

QUOTE] Yeah , After the second time it went out , back when it was bitter cold out , I removed the box and it still had issues working cold . I did not remove the splicing into the harness tho. So I cannot rule out the wiring to the box as being the problem . I'm afraid to open the splices as the original cuts left pretty short wires to work with . Which is also why I was hoping to find the problem upstream from the box .
I suppose it could still be anywhere in the loop including the box .

Seems to be working fine now ....

 

[96r50]

Check the ground wire that attaches to the rear of the intake. This is the ground for your speedo. Chances are you may have loosened it while doing your PM or it just has a bad connection.

I checked mine and found that it was connected in the wrong spot, sharing the bolt with the top mount of the ATF dipstick. I moved it to the original spot with a lot of reaching and squeezing (it's tight between the intake and brake booster). After a few drives, I think/hope this has fixed the odd cruise control pulsation I sometimes get. Thanks Kerry!

 

[Scalci]

Can someone share a photo of this wire?
I removed the dash & instrument panel today Could not see anything wrong, except when I removed the speedo instrument from the cluster, I saw on the top, it looked it there was a short, I cleaned it, test with a tested for continuity, and all looked ok, but am not sure if something blown.

Put it all back and still no speedo and ODO..

 

[thirdmatt01]

i am having the same issues, did you ever figure it out?

 

[Kaid000]

I am having the same issues but all threads regarding this matter end as this did. Please help!

 

[ampline]

I am having the same issues but all threads regarding this matter end as this did. Please help!

Hello, I'm curious if you ever figured this speedo issue out? I am in the same boat. And for some reason I can't find if a remedy has been found.

My speedo only works once warmed up, and today the "OD Off" light began flashing.. came home, ate, then I took another drive... speedo works and no OD off light.

Next time I drove it. No speedo

Curious if anyone has found the solution. Thanks

 

[ampline]

I am having the same issues but all threads regarding this matter end as this did. Please help!

Did you ever figure out your speedo issues? Still trying to figure mine out. Thanks

 

[panamacruiser]

As someone said, IT IS the ground cable from the sensor, just add an extra grounding cable and you shoul be ok...you should have a red, green and yellow(orange? I'm color blind) most likely the green is the ground (can't remember from the top of my head) ...again leave everything as it is and ADD an extra ground

 

[ampline]

As someone said, IT IS the ground cable from the sensor, just add an extra grounding cable and you shoul be ok...you should have a red, green and yellow(orange? I'm color blind) most likely the green is the ground (can't remember from the top of my head) ...again leave everything as it is and ADD an extra ground

So I have 3 wires, brown, yellow, and red/green stripe. I don't have my FSM with me (forgot it at my friend's house)... do you happen to know which is the ground?

 

[cjmoon]

I've chased wiring items all around with my swap. All the grounds are connected but for what ever reason the couple grounds on the driver side of the engine cause all kinds of issues. There are 3 if I remember right of course mine are not in the factory locations. I even put a newer sensor from a 2005 land cruiser in that is not gear driven because I had it laying around. Zero change before finding the ground I had missed.

 

[ampline]

I've chased wiring items all around with my swap. All the grounds are connected but for what ever reason the couple grounds on the driver side of the engine cause all kinds of issues. There are 3 if I remember right of course mine are not in the factory locations. I even put a newer sensor from a 2005 land cruiser in that is not gear driven because I had it laying around. Zero change before finding the ground I had missed.

Thanks. Ive located, removed, and cleaned, and re-grounded all the grounds I can find. Yet the VSS1 is still throwing a code 42 until the intermittent speedo starts working. Then the OD OFF light stops flashing and code goes away.

Once speedo is working, cruise control works too. But it normally takes about 20 minutes of driving before speedo starts to work (after a minute or two of it bouncing around).

I was thinking about adding a ground as PanamaCruiser suggested. I don't have the wiring diagram in front of me though. Thinking brown is ground, but I don't want to guess.