Ijust installed and started a rotary resurection rebuild in my 86 n/a. Prior to attempting to start, I primed the oil system per Kevin Landers instructions(removed EGI fuses and cranked a couple of times). Oil pressure gauge went off the high end, over 110. Car runs good, but I'm afraid to continue running it with the high oil pressure. Sending unit and gauge worked prior to the rebuild. Won't hold an idle, but I guess that's to be expected for now.

 

Verify pressure is too high with a mechanical gauge...There's really nothing that's going to get you that high unless the pressure regulator has been shimmed or is somehow TOTALLY stuck closed...even then you wouldn't get that kind of pressure at low RPM.

 

1st thing to check, before you jump to conclusions: If you just turn the key to "run" (don't start the car), does the gauge go all the way up? If so, congradulations, you're like me with a broke oil sending unit. Go buy a autolite gauge for 45 bucks from a local advance/A&A/AutoZone.

 

Thanks for the replies, When I turn the key to "run" it does indeed go all thw way up. Is this a sure bet(replacing the sending unit), or should I spend the $ on the mechanical gauge? I'm short on $ right now(another broke rx7 owner!). If its definitely the sending unit, is it okay to run like this for a week or two before replacing the unit?

 

If it jumps all the way up immediately, it means that the gauge wire has been shorted to ground or the sender is bad (dead short).

 

Lets see here..... 57.50 for a new sending unit (less Shipping) from Mazdatrix

OR 49.95 for an autometer sport comp gauge with an electrical sending unit, or 38.95 for a mechanical gauge (have to run a nylon or copper tube) and a few bucks for the port adapter.... Oh Yeah... and like 28 bucks for a dual pillar gauge pod.

Hmmmmmm, I know which one I'd Go for.... i'd spend the extra bit o cash and get the autometer set up, I'd go with the electrical gauge too, but some guys swear by mechanical...

But mess around with your wiring like Arron says cause it may just be a short

 

Well, I would replace the sender as well. Having a dead gauge would bug the hell out of me, and a used sender would be dirt cheap.

 

I have the exact same problem. I really want to get it broke in so i can enjoy it a bit before winter hits, but i am very leary about driving a fresh rebuild with the oil psi gauge not working correctly. I am going to be getting a new sending unit asap to see if it fixes the problem.