Will a 87 4runner fuel gauge sending unit work in a 87 pickup?

 

It should, they both use same engine 22R-E, and share same schematic.

 

Sorry failed to mention I have a 22r

 

I went ahead and replaced the sending unit with one from sunpro with a matching gauge. Problem is now it reads over full continuously. Any ideas?

 

Can you post part numbers of the gauge and sending unit? Maybe a link to some install instructions?

What resistance is the sending unit? And gauge? Is this a universal sending unit or specifically made for an 87 Toyota Pickup with 22R?

 

I can get numbers later. But it was a universal unit and gauge that were matched to be the same ohms.

 

This one? http://www.sunpro.com/product_detail.php?pid=16355

It shows "full" at 33 ohms. So "over full" is probably less than that, as in, shorted (zero ohms).

Start with the easy test; stick a multimeter on the sender leads (with the gauge disconnected). Does it read zero ohms (or anything less than 5 ohms)? You've got a short.

 

Then something sounds messed up. (duh). On an 87 EFI 4Runner the sender wires goes straight from the tank through a body grommet and then there is a connector near the passenger kick plate right next to the ECM. Then from there it is a straight shot to the gauge.

How is the gauge and sender grounded? They must use the same ground in order to work properly.

If your gauge reads low resistance as full and the grounds are messed up or the sender wire is cut somewhere the gauge will read 100% full.

When you say it reads over full.....by how much? Way past full or just a little bit?

EDIT.....Scope is on fire today. He types too quick. Do whatever he says and no one gets hurt.

 

I have the gauge and sending unit grounded 2 different places that may be the problem

 

Alright moving the ground didn't change anything. With just the gauge ground plugged in I get 1/4 tank. With no ground I get 1/2 a tank. With both grounds or just the sending unit ground the tank pegs past full.

 

If no one has any ideas I'm tired of messing with it. Can anyone tell me the part number of a OEM sending unit for a 87 22r pickup with a 17 gallon tank only 2 wires on the old sending unit

 

You're welcome.

You may be able to find your sender here: http://www.toyotapartsoverstock.com/...driveLine=6707 It doesn't give it by tank capacity, but you'll figure out which option you have.

Before I went the $140 route, I'd at least try pulling the sender, and just hook it up to the gauge. With the sender in your hand, work the float to see if the gauge swings. If it doesn't, it's definitely not a grounding problem. (whether it's a defective unit depends on a lot of things I don't know.)