oil pressure sender types - Toyota Nation Forum : Toyota Car and Truck Forums

Mr2Fixer · 10-03-2004, 01:10 AM

I just swapped out my instrument gauge cluster from my 84 4Runner.

The old cluster didn't have a tachometer or full instrumentation. The "new" one I got off Ebay has all the dials on it.

It works except the oil pressure gauge seems to be working in reverse. It reads high when the engine isn't running and then drops down when running.

This might be one of those sensor/instrument gradient issues. Like the question of whether your TPS increase or decreases voltage as you open the throttle.

Advice is requested. And I will pay back the board by helping others when I can in the future.

Mr2 Fixer

toy283 · 10-03-2004, 05:49 PM

You need to get a sensor to match the instrument cluster. The sender for an idiot light is a simple on-off switch, there is no gradient as is required for a gage.

Mr2Fixer · 10-04-2004, 12:13 AM

Hmmm I thought it would be something like that. . . . . . but wasn't sure.

I wonder if I am really ready to assemble and install a DYI engine management system like Megasquirt? Being uncertain of oil pressure sender types makes me wonder if I am ready.

Thanks for the info Toy283

alltrac165 · 10-04-2004, 11:21 PM

There appear to be 3 types of senders. The simple on/off idiot light, the actual variable signal oil gauge sender, and the "idiot gauge". The idiot gauge has no contact with no oil pressure, then makes a 48 ohm or so connection(if memory serves) to ground. This is what I have on my 90 Runner. No matter what the oil pressure is, as long as it's above the low pressure cut off, I get the exact same reading. Kill the engine and it drops to an open circuit. Same function as a dummy light but backwards in that an idiot light makes contact with low pressure and opens with pressure. Kinda retarded, really. I always thought I had a pressure gauge, but I don't. It never changes it's position. I even checked on a couple other Runners up to 93, and it's the same deal. So make sure you get the sender that came on the same model as the dash unit.

Mr2Fixer · 10-05-2004, 02:27 AM

Strangely enough, I found a sender from an 85 Celica with a 22r in it.

Installed, it doesn't work at all.

And it did test at 45 ohms at idle and no change with revving. I figured it for a dead part. Nope its just the wrong one apparently.

By the time I am finished I will have held all three types in my hands.

Thanks for the little extra bit of information that makes the whole picture come together.