Temp Sending Unit?

[LifeIsGood]

The 62's temp guage was acting strange the other night. I was on a 30 mile drive in 40 degree weather. Guage read normal through the "warm up" the first few miles. I then noticed that is was fluctuating in a weird manner. It is normally rock solid after warm up no matter if it is winter, summer, up hill or down. But this time is would move up toward the "red zone" quickly then back down in a matter of say 5-10 seconds. This seems way too fast to be an accurate reading. I have seen sending units react to air bubbles in this manner, but I checked the system and found it to be full and the hoses to be firm with coolant. I don't think there is air in there, but it could be a possiblity. What do you guys think? Normally when the TSU goes bad it either doesn't work or pins in the "red zone" I've never seen it "bounce" back and forth from normal to hot. What gives?

[Landpimp]

its not the sender, its the fuel guage actaully, the temp gauge and fuel gauge share the same ground contact which is on the fuel gauge, clean the little points up and it will be fixed, if not get a new fuel guage(about $35) More often then mot the temp and fuel gauge will both act up.........did you notice the fuel guage bounce or peg out at the same time?

[LifeIsGood]

Landpimp, this is why Ih8mud is such an awesome resource. I would have wasted so much time and money chasing ghosts and never guess that it could be a problem with the fuel guage! So you are suggesting I take the dash apart and get at the back of the guage cluster to clean things up and look for a bad ground? BTW I did not notice any problems with the fuel guage, but electricity continues to amaze me. It will do some strange things.

[Landpimp]

someone showed me

yes take the cluster/dash out(its super easy) and then the fuel guage out. On the back of the fuel guage you will see a little points contact, clean it with some emory cloth(or something like that) To be honest I got mine so it happened less often(it will get worse and worse) but decided I didnt want to have to worry about it for anohter 100K+ so I bought a new guage.

this is the old one, just happen to come across it today.

screw driver is pointing at the contact(that they both share)


close up

[LifeIsGood]

Thanks again Landpimp.......you rock!!

[scottie]

I can't say how many people I asked about this, even the Toyota people. I tested my gauges, replaced both temp sending units, thermostat, and had my fuel sending unit replace when I got my fee new gas tank from the Toyota recall, but nothing fixed the problem. The last thing left, other than a ghost in the system, I should have came here first. Great knowledge on this site. Thanks for taking the time to put it out.

[cleatus]

would a 60 be set up thesame way. as my fuel gauge does not work and the temp is usually cold( although that is proably acurate)

[DirtyLittleSecret]

Im kinda in the same bucket. My temp wont even warm up past 1/4. Thinking its either toast or the cold weather is doin' it. I sincerely doubt that the PO ever changed it. Will probably just change it out to feel better.

[cleatus]

Originally Posted by DirtyLittleSecret

Im kinda in the same bucket. My temp wont even warm up past 1/4. Thinking its either toast or the cold weather is doin' it. I sincerely doubt that the PO ever changed it. Will probably just change it out to feel better.

I've changed my thermostat twice and it still barely gets off cold. i would say the gauge is broken but it worked when it was overheating and ona warm day it would warm up. bad part is when it ran warmer i got like 15mpg running cold i get 8-9mpg

[DirtyLittleSecret]

Huh. Just calculated over 17 mpg with my first tank the other day. How are you guys getting these MPG? Cant hurt to replace the TS!

[mtb_rider]

Originally Posted by Landpimp

its not the sender, its the fuel guage actaully, the temp gauge and fuel gauge share the same ground contact which is on the fuel gauge, clean the little points up and it will be fixed, if not get a new fuel guage(about $35) More often then mot the temp and fuel gauge will both act up.........did you notice the fuel guage bounce or peg out at the same time?

That's what I was thinking. Occasionally my temp and fuel gauge will both spike for a few seconds, then come right back down. I figured they probably shared a ground, as that's really the only reason they would both do it at the same time. It just hasn't bothered me enough yet to try and chase it down. But when it does, I know where to go now!

[Oscar V]

Niiice, Now I can fix mine too thanks guys

[hank14]

Anyone have current pics of this? Landpimp's pictures are AWOL. I took my instrument cluster out, but did not remove the actual gauge. Everything on the circuit board looked so clean, I couldn't believe it's 20 years old.

I also took my truck in to be inspected (saftey inspection, no smog in my county), and the horn wasn't working, so I disassembled the horn and cleaned the contacts in the Wal-Mart parking lot. Now it's good as new.

[REKCUT]

You need to put in a mechanical guage so you can get true readings and not just somewhere around the 1/3 mark. It will also allow you to get a reading after the truck is turned off so you can see how its cooling down. Very inexpensive and easy mod

[cruiser88]

Originally Posted by REKCUT

You need to put in a mechanical guage so you can get true readings and not just somewhere around the 1/3 mark. It will also allow you to get a reading after the truck is turned off so you can see how its cooling down. Very inexpensive and easy mod

YES

[hank14]

I agree, and plan to do that before my first big road trip. I also plan on keeping the stock gauges as well, and would like to get them working normally (which they have done except for the 40 mile trip when I drove it home the first time).

[cruiser88]

Originally Posted by hank14

I agree, and plan to do that before my first big road trip. I also plan on keeping the stock gauges as well, and would like to get them working normally (which they have done except for the 40 mile trip when I drove it home the first time).

If you go with the aftermarket in a 62 you will loose the factory temp guage, along with the oil pressure guage

[TLCAddict]

Landpimp...
just bought my 88 FJ62 about a month ago, and exact same thing happened to me on the fwy...both spiked for about 10-20 secs, then back down. thx man for the spec n analysis...do you recommend keeping the old gauges, just in case; and should I replace w/ OEM or aftermarket?

[Bomar]

TLCAddict,

Give cruiserparts.com a call and get a used gauge from them. I just got a few and straighten everything right out.