Have a 89 toyota pickup with the 3.slow. For about a year after doing my head gaskets my oil pressure gauge hasn't been reading for some reason. I first assumed the sending unit was bad, but after paying 40$ for a new one nothing changed. I grounded out the wire the connects to the unit and the gauge did work so im stumped and been at the same place for a year. Any ideas are appreciated

 

Maybe your engine needs more grounding wires or sending unit isn't connecting to the block . Try running a ground wire from the body and touch it to the sending unit body so it grounds it to see it it works .

 

I have tried grounding the wire out and gauge does work, as i did mention in the original post?

 

Hook up the sending unit like it should . Then try a wire from truck body ground to the sending unit housing . If that works then you know your engine is not grounding good . If that doesn't work then I think it's your gauge not working fully . Or Maybe some gunk built up where the unit screws into. Take out unit , Unplug coil , turnover motor a few times to see if oil comes out . Just some ideas.

 

Okay will try those and get back to you thanks

 

Also no telfon tape or pipe dope.

If you need a sealer get one that conducts electric

 

Well i ran a wire from the body to the unit housing but still nothing (could of been the pos wire i had) then i unscrewed the unit and turned the motor on for a second and holy shi* did that make a mess. Glad to know its defiantly not plugged. Also grounded out the plug that connects to the unit and my gauge did respond. So i really am stumped. There was a wire which was cut off connected to some plug right by the coil that ran to a ground. I couldn't trace it down where it connected to but thats the only thing i could think of. I have a picture but this site wont let me upload it from my phone for some reason?

 

So i found out its a capacitor i believe. And its bolted down with the same coil bolt. One wire runs to the block of the motor along with another ground wire and the other end is just hanging there by a plug which is cut off? Have no clue where it goes to.

 

where would the major ground for the motor be located?

 

Usually a ground strap wire looks like thin flat woven wire with no cover on it . Could be around motor mounts and you might find smaller along top of motor. My friend that's a Toyota mechanic told me lots of electric problems he sees are from bad engine grounding . You obviously have some kind of ground or your motor wouldn't turn over . I think you have gauge problem cause you eliminated any problem with the sending unit . I swapped a gm 4.3 in my Toyota and used a Toyota oil sending unit . I wired it to the plug in the body by the kick panel then it goes right to the gauge. So there should be nothing electrical in between .

 

just get an aftermarket. stock gauges are not accurate, at all.