oil pressure guage

[roadrunner440]

ok guys heres one that has me confused i just bought this 73 runner but with lots of electrical issues i got most fixed now excep the oil pressure i grounded out the wire the guage, goes to high but slowly so then i thought it was the sending unit i put one in with the needle not moving much ok then i thought i had a bad sending unit nope i bought 2 sending units from difrent sources and still the same is the guage bad?? or what else??? and by the way does any one know or have door jamb switch 4 a 73 or 74 rr with uses 1/2 inche thread insted of a 3/8 or 5/16 i cant seem to find any anywhere, any help would be great thanks again

[roadrunner440]

can any one help?

[Chryco Psycho]

you should have a pulsing voltage into the gauge , when the wire to the sending unit is grounded it should move to full which you have tested & it seems to work . So that would mean everything up to the sender is working properly so either the sender is bad or it is not grounding properly where it is mounted . The other option is the engine is not making pressure , have you tested it with a mechanical gauge ?

[roadrunner440]

the sending unit is located on the rear of the engine the guage goes to full when grounded i used a jumper wire with alagator clips and ran it from wiire to sender to the bold on alt it went to high can a enginge run with no oil pressure needle doesnt even come to the low mark i have not checked w mechanical guage

[Chryco Psycho]

yes an engine will run with minimal oil pressure . you could also be bleeding off oil pressure at the lifters if they have too wide groove or a bad oil filter or oil pump not producing oil pressure

[roadrunner440]

so should i replace or change the oil and filter n oil pump n lifters

[roadrunner440]

ive noticed that lifters tick for a while till engine is warmed up

[roadrunner440]

so the engine is toast

[y3chargerrt]

Test the oil pressure with a mechanical gauge first before replacing parts or assuming the engine is toast.

[roadrunner440]

if the guage goes to full when grounded out and put in 3 sending units wouldnt that asume u have no oil pressure could the guage still be bad?

[Chryco Psycho]

you can get a mechanical guage for $20 ,l would test first before spending $ on parts you may not need !
If it has a big block the oil pump is outside the engine & easily swapped maybe all you need is a new pump but I cannot find a reference to the engine you are working on . I have seen brand new engines have zero oil pressure because the lifter groove was too low & bleeding all the oil out , there are a lot of possibilities other than the engine is toast , start with an accurate oil pressure reading .

[Ghoste]

And do it soon before the engine is toast.

[roadrunner440]

i tried a mechanical guage and 65 lbs at idle and 75 lbs at 3000 rpms the guage tries to cume up it flickers a few times the drope way blow low when i came up never when past low it the guage shot? any help would be help full thanks again pat

[Chryco Psycho]

good so the oil pressure is OK 
which sending unit do you have , it should be a Bell shaped unit 1.5" in diameter & 2.5 " tall ?

[roadrunner440]

ya its a canister type wich uses a female spade type conector so should i replace the guage ? ive only tryied three sending units but go figure u think the guage can still be bad and doesnt look like a easy job to replace i broke the center to night takeing out the guage out of the rally dahs my spare i  hope the glue holds lol?

[Chryco Psycho]

I doubt it is the guage if the gauge swings to full with the wire grounded . are the fuel & temp gauges working ok ?

[roadrunner440]

yes both temp n fuel guages work but oil guage tries to come up then flickers n drops below low again it sounds like the guage to me i guess im not realy good at the electical part thats y i need some help here i think im going to try a difrent guage thiss weekend somtime any help would be help full thanks for every ones help