SR5 cluster in 1990 Pickup RN101L

[Matt Sierra]

I've installed a SR5 cluster in my DLX 1990 4wd pickup with 22re and haven't been able to get the oil pressure gauge working. I replaced the oil pressure sender with the correct unit for a gauge (83520-35032) and have followed the factory service manual troubleshooting guide. I can light a 3.4W test bulb when I ground the wire to the sender through the bulb but the gauge moves very slowly and irregularly. I can't light a 3.4 W test bulb when I run a wire from battery + to the sender with the engine running. The gauge has resistance within spec (24.6 ohms).

Questions:
1) Does the gauge normally move quickly (like the battery gauge)? Or slowly (like the fuel gauge)? I was expecting it to respond quickly when I start the truck or connect a test light.
2) Has anyone ever had a bad sender? I get oil leaking out of the sender hole when I remove it, so that isn't clogged, but it seems unlikely that an OEM sender would be bad.
3) Any other testing that anyone recommends aside from what's in the FSM?
4) Should I check out the wiring any further? I assume if I can light a 3.4W test bulb that's not the issue.
Thanks.
-Matt

 

[aztoyman]

Maybe the oil pressure side of things needs to be checked. Can you rig a way to apply pressure to the sensor?

 

[jgranthevagrant]

My gauge responds fairly quickly on start up. then follows rpms for pressure. It is new to the truck since June, because the original hadn't worked for 15 years. Maybe you can find a spare cluster and just swap the gauge?

 

[Matt Sierra]

Maybe the oil pressure side of things needs to be checked. Can you rig a way to apply pressure to the sensor?

I’ll see if I can find the right combination of fittings to attach the sender to a section of threaded pipe I can connect to my compressor and pressurize. It should still be cheaper than buying another sender.

I’ll see if I can find a known good cluster locally or on eBay. I’m a little unsure about testing with an eBay cluster because people do burn out the oil gauge with the senders intended for clusters with an oil light.

 

[Matt Sierra]

Maybe the oil pressure side of things needs to be checked. Can you rig a way to apply pressure to the sensor?

Turns out the sender is 1/8" NPT threaded, so I just need a 1/4" to 1/8" NPT female reducer and I can connect the sender directly to my air compressor. I'll also attach a mechanical gauge to the sender port to confirm the oil pressure I'm expecting.
Edit: I was wrong, it's 1/8" BSPT.

I'm still trying to track down a known good oil pressure gauge and have a few leads I'm working on. If anyone has one they're looking to sell, PM me please.

 

[aztoyman]

I think Toyota uses 1/8 BSPT threads on the sensors. Pretty close to 1/8" NPT but not the same. Might be close enough for you to test it through.

 

[Matt Sierra]

You're absolutely right, it's 1/8 BSPT. Fortunately I can just pick up a 1/4 NPT to 1/8 BSPT reducer instead.

I've decided to pull the gauge and test everything on the bench. It's a simple circuit so once I have the adapter, I'll wire the gauge directly to the sender, will connect the sender to my compressor, and will give it 12 V.

Honestly I should probably just move on, I didn't have an oil pressure gauge for 23 years and it didn't bother me. But once something triggers the OCD...

 

[gnob]

You're absolutely right, it's 1/8 BSPT. Fortunately I can just pick up a 1/4 NPT to 1/8 BSPT reducer instead.

I've decided to pull the gauge and test everything on the bench. It's a simple circuit so one I have the adapter, I'll wire the gauge directly to the sender, will connect the sender to my compressor, and will give it 12 V.View attachment 4202732

Honestly I should probably just move on, I didn't have an oil pressure gauge for 23 years and it didn't bother me. But once something triggers the OCD...

i learned after several thousands of miles behind the wheel, the less gauges, the better the driving experience

 

[Matt Sierra]

i learned after several thousands of miles behind the wheel, the less gauges, the better the driving experience

Honestly, driving the truck free of all gauges (and a dash) was a lot of fun. Probably not a great idea at night though.

 

[Matt Sierra]

Bench test confirms that I had two bad gauges. For future reference the bad gauge still seems to result in a normal 0.14 amp current, just the gauge doesn't move (see photo). The new gauge I've sourced seems to respond quickly when I complete the circuit. Next step is to throw everything back in the truck and make sure it still works there. If not, I must also have a wiring issue.

 

[Matt Sierra]

The oil gauge is in and working, so I don’t have to sort out a wiring issue.

Now just got to calibrate the tach and replace the bulbs in the cluster and I can finally get the dash back together. Getting to the tach potentiometer is pretty fiddly without disconnecting and pulling the cluster out entirely, so I’m expecting a lot of guess and check.

 

[svsisu]

Bench test confirms that I had two bad gauges. For future reference the bad gauge still seems to result in a normal 0.14 amp current, just the gauge doesn't move (see photo). The new gauge I've sourced seems to respond quickly when I complete the circuit. Next step is to throw everything back in the truck and make sure it still works there. If not, I must also have a wiring issue.
View attachment 4205994

Where were you able to source a new gauge? I'm on the hunt for one for a 97 T100 with 5vz-FE.

 

[Matt Sierra]

Where were you able to source a new gauge? I'm on the hunt for one for a 97 T100 with 5vz-FE.

I wasn't able to find a new one, unfortunately. If there's anyone out there with new old stock I couldn't find them. What does your gauge look like?

I got the two used ones that didn't work on eBay and got the working gauge from a used parts place in SoCal called Yoda Gang. Yoda Gang - https://www.yodagang.com/

 

[svsisu]

I wasn't able to find a new one, unfortunately. If there's anyone out there with new old stock I couldn't find them. What does your gauge look like?

I got the two used ones that didn't work on eBay and got the working gauge from a used parts place in SoCal called Yoda Gang. Yoda Gang - https://www.yodagang.com/

I'll grab a photo and post later. It's similar looking to yours, but I think slightly different. They are notorious for going out, or like you said, the wrong sender being used which tweaks them. I'll have a look at Yoda Gang, thanks!

 

[Matt Sierra]

I'll grab a photo and post later. It's similar looking to yours, but I think slightly different. They are notorious for going out, or like you said, the wrong sender being used which tweaks them. I'll have a look at Yoda Gang, thanks!

There are a lot of bad gauges floating around because most clusters come from junkyards that don't test their clusters.

If I had a chance to do it all over, I'd bench test the gauge as soon as I got it. It would have saved me a lot of second guessing and troubleshooting of components that weren't at fault. Hopefully Yoda Gang can help you out!