I picked up a rx7 vert today and oil pressure seems real low it is just above 0 at idle and about 30 at 3k rpm. Is it a pretty good chance that the sending unit is off

 

thre is a good chance the sending unit is bad. they go all the time. but I wouldn't risk driving it till I found out for sure. stick a mech. gauge on for a test.

 

There's a very good chance that the connector to the sending unit need to be cleaned.

A quick and dirty way to check your pressure is to squeeze the oil cooler line when someone is revving the car to like 2k. The line should be VERY firm. If it's not, you have a problem.

 

Zero pressure at idle with 30PSI at 3K is a classic indicator of a blown front cover o ring.

Confirm the reading with a good quality mechanical gauge before you tear into your engine.

 

yip sure is, i had that problem, around 5-7psi pressure at idle once up to temp, when cold it was 20psi, replaced that oring - couldn't find one there and now its all good

60psi at 2000rpm

 

Well I've driven the car 180 miles including stop and go traffic. I am sure you guys are right. Maybe next weekend I will look at it.

 

Hmm.. Is this hard to replace?

I had "normal" (30@idle, 60+ at >2k) readings before I replaced my oil pressure sending unit, which i suspected was leaking.. (turns out it was the oil filter o-rings..heh). With the new unit, it's more like ~10 at idle and ~45 at >2k... Freaked me out, but I drove it anyway.. I've put maybe 5000 miles on it like this..hehe..

Hm..I should prolly check it with a mechanical guage... Maybe I just got a bad sender unit....

-Tesla

 

set aside at least 6-8 hours of labour time to strip it and put it back together

you need to remove the front cover which means removing the water pump housing, which means to make things easier you might as well pull the radiator so you can get in there easier.

 

Thats sort of a gimme, is'nt it? Worked good one moment. Changed the sender. Does not work good. You've double checked the connector is on the unit good and clean. Senders are a suspect item on RX's. Put the old one back on and see if you can get your money back on the new one. That said, I out of ignorance and before Mazdatrix ever had a FAQ, put the front cover o'ring on wrong which resulted in almost zip oil pressure at idle and something like 40-50 at 3000. Had to pull the front cover and reassy without the front gasket and only the o'ring in place. I've got at least five spare oil senders, all of which read different figures on the same engine. I put a mech oil gauge on to test. Drilled a hole in the banjo bolt in the rear oil cooler hose bolt and tapped threads for a cheap aftermarket unit from PepBoys to get a more realistic idea what the pressure was.

 

It did the same exact thing on my 90GXL. But prior to that my gauge was reading 110PSI regardless of RPM. So I figure my sender was going bad. I had it replaced just recently and it's reading just like it should. Lucky for me I didn't have to tear into that front cover seal, for now at least.

 

FYI..... Today I took a *bad* oil sender unit and made it *good*. The *bad* unit was reading low compared to the mechanical gauge I have patched in. This site http://k2rd.freeservers.com/FC3S/PRO...IL/OPS/ops.htm shows how the gauge can be taken apart. With it in your hands you can see the four locking tabs that hold the top on. Then you have to gently pry around the edges so the two halves can seperate. Just takes a blade screwdriver and a 14mm wrench. Once apart you'll see a geared plastic wheel with a ramp. To decrease the reading turn the gear anti-clockwise the width of a tooth, then put the thing back together in a temporary manner. Reinstall. Start engine and compare your mechanical with the new reading on the factory gauge. Should'nt adjust more than a tooth at a time. Took me three tries before the gauges matched. I put rtv around the joint where the two parts mate to seal. Do as you please. Works for me. At least one day. Yes, it reads zero with the key just turned on.