WonkoTheSane

iTrader: (2)

A few days ago, when I was leaving work, I started my 86 GXL, and as I was pulling out, I noticed my oil gauge was STRAIGHT UP AND DOWN! I mean, it has markings for "0, 30, 60, 110" but this was 90 degrees from horizontal! At first I panicked, shut everything down, checked to make sure nothing was smoking (no more than normal), my oil looked fine, i didn't appear to have any abnormal amount of leakage... So i figured it must not have been criticle, or it just didn't go boom yet.

So i turned the key, (didn't crank the engine).. and the gauge shot up! Then i realized, hey, wait, this shouldn't be pumping oil unless the engine is on, right? So I turned it on, let it idle.. seemed to be doing that fine.. everything else seemed in spec.. i let it on while i did a quick inspection in the lot, no problems.. So i drive it to go get gas. Nothing interesting happens, other than the gauge never drops down..

The only interesting thing happens when i drive on the highway (on the way home). I slowly accelorate (just in case something is wrong, i want to take it easy). and when i set my cruise to 70/80, the oil pressure slowly drops down to normal for that speed (on or below the "60" mark. or is it 90? I dunno, the one that's not the highest mark).

When i get back to town, drop it into neutral to coast off the ramp.. And my guage went back up.. was straight up and down since.. unless i drive at 60+, then it will slowly go down...

Sorry about the length, i just wanted to cover everything... any good ideas?

one side note, i changed my oil last week, is there a possible way i bumped something or anything along those lines when i did it? (I mean, pretty simple procedure)...

THANKS!

DaleClark

iTrader: (55)

That's the oil pressure sender going out - that's one of its' failure modes. I would unplug the sucker for right now - with the sender putting out that high of a signal, that will burn up the oil pressure gauge in the cluster. I've seen that one happen before.

A good used sender should be cheap and easy to find - they're all the same, '86-91, turbo and non-turbo.

Dale

WonkoTheSane

iTrader: (2)

Is it going to be detrimental to the car to run it w/o the sender?

LT1-10AE

Either the wire for the pressure sensor is grounding out, or the oil pressure sending unit is going out which is very common.

Examine the wire going to the sending unit and make sure it isn't chafed on anything causing the ground. You might also try cleaning the connector and see if it helps. Grungy oil on a motor usually won't conduct enough to cause this problem, but then again there's a first time for everything!

WonkoTheSane

iTrader: (2)

I'll check all the wiring and connections t/w before work.. break out the haynes manual and see where all this stuff is.. Will it hurt anything if the sender is dying? I mean, how criticle is it to get it replaced, are we talking something that needs to be done today, t/w, next week, next month...? thanks

LT1-10AE

You can run with the unit unplugged with no problems. The car won't act up or give you any problems (unless you DO lose oil pressure). All the sending unit does is move the needle on the dash so you can see how much oil pressure you have.

The sending unit is just below the oil filter. It's about 2" in diameter and sticks out towards the driver's fender about 2". There should be one wire connected to it that will slide off the sender. It doesn't pull straight away from it.

nashman69g

iTrader: (3)

this same exact problem happen to me... It freaked me out but after a week or two it started to work like normal again... I haven't had a problem since.

WonkoTheSane

iTrader: (2)

odd.. thanks for the help guys i'll get it fixed in a jiffy...



okay, really, i just wanted to use the word "jiffy" in a sentance

rx_7_driver

ok since we r on the topic mine was doing this about a month ago and now most of the time it sits at 0 at idleing and and get alittle above 30 when crusing 50+, whats the problem??? cause sometimes it will still go above 110 and sometimes it works just fine (right under 60 crusing around 60-70mph) also sometimes i can see a spark from a wire (don't know which wire) on top the tranny and it looks like the only way to get to it is to pull the tranny out the car, is this the oil pressure wire? if not where doese the wire go to ? and whats the wire on top the tranny? (i am asking this because i realy don't have time to pull the tranny out and fix this cause its my daily driver unless it can cause a major problem ) also the car still runs fine as of now but will it cause aa problem later on?? if someone knows please let me know

-Shawn (Hurricane Lili = Hurricane Party = Beer = Drunk)

tesla042

uhm...sparks are prolly bad.. I'd try to find out what wire that is..

Your low oil pressure could be a few things.. The front cover o-ring, when it goes out, significantly reduces oil pressure. Or, when the oil bypass thermo pellet fails, it can reduce oil pressure too.. The pellet fix is pretty easy, and it's generally a good idea to do it, since in "failure" mode, it bypasses oil away from the bearings of the engine..

If you're going to get in there and replace your sender (which is a VERY common place for oil to leak... have any leaks?), you may want to also replace the oil pedestal o-rings (which is another VERY common place for oil to leak).. http://haxx0r.net/car/rx7/oil_ring/ has a writeup I did for replacing it. You can see the sender in the picture at http://haxx0r.net/car/rx7/oil_ring/no_oring.jpg -- it's the goldish-looking thing in the middle.

Or, it could just be a bad guage or sender.. The "real" way to see what your oil pressure is doing is with a mechanical guage..

-Tesla

WonkoTheSane

iTrader: (2)

thanks for the write-up.. i'll be ordering those seals in a day or two (I dunno if i need em or not)