Ok, so you know how when you go to start your car (88's at least) and the temp light doesn't come on for the bulb check, but the gauge needle swings all the way? Well, my oil pressure gauge just started doing the same thing, intermittantly. Sometimes, the light comes on and it stays at 0 like it should (key on, engine off). Other times, the light stays off, and the needle pegs.
Also, sometimes when driving, the needle will peg for a few seconds, then return to normal. The reading seems about right when it's not pegged. (about as right as these gauges can be, I guess). Since it's a new development, something has worn or changed. Any suggestions?

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"We will always remember. We will always be proud. We will always be prepared, so we may always be free" -- Ronald Reagan

Bad connection at the gauge or sending unit? Fiero's are also notorious for the oil pressure sending unit going bad.

I'll check. That would make sense on the pegging gauge, but not so much the light going out, I don't think. The gauge is pegging because the power that's supposed to light the light is being routed to the needle, somehow. When the gauge comes back to normal, the light come on (engine off, key on). The two are connected, somehow.

Probably a stupid question, because I know you're meticulous with your car, but is it possible the car is low on oil?

Last year, when I first got the Formula, the gauge was acting pretty strange, and it had been a while since the oil had been changed (lost track of how many miles were on the current oil change, and it was icky cold weather out, so I didn't want to mess with the car much), and the oil was pretty low... I figured maybe that the sending unit wasn't getting a solid signal due to the oil being so low.

Dumb suggestion, I know, but it's the only thing I've experienced personally, other than your oil pressure sending unit crapping out...

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Patrick W. Heinske -- LZeitgeist@aol.com
1988 Red Fiero Formula
- 1st Place - Stock Coupe - FOCOSEVA 2000
- 3rd Place - Stock Formula - FOCOA Nat'l 2001
- Class Winner - 1982 to Present - Tarheel Tigers All-Pontiac Show 2001

There are no stupid questions. Just stupid people asking them. (note: that was a joke, for the sarcasm impared)

Oil level's fine. If it were just reading flaky, that would be one thing. The weird part is how the oil light and gauge are connected. With the key on, engine off, the gauge should read "0" and the oil light should be on for the bulb check. Sometimes it does this normally, other times, the oil light doesn't come on and the gauge pegs.

It's so intermittant, that I've noticed a couple of times sitting with the key on, engine off, the oil light will come on, and the gauge returns to zero, then the light goes off and the gauge pegs. This is all with the engine not running. So, somewhere in the wiring, the power for the oil light is getting to the gauge needle. It's the exact same behavior as the Temp light/gauge, except it doesn't always do it. Also, occasionally when running, the gauge will peg for no apparent reason.

Anyone have schematics of the gauge/idiot light cluster?

When mine started and acting funny at times I changed the oil pressure switch and it corrected it. also I think I am going to have to change it again because it is acting up again. I installed the other one three years ago . I have read many reports about these senders going bad and the next one I buy I am going to try a different brand other than GM.

I believe there is only one wire feeding both the guage and light, so it would make sense that the light would be out when it pegged. Mine has done pretty much the same thing for quite a while. I've always assumed it was a bad sender since I've heard they were notorious for going bad, but I've never gotten around to fixing it.

Other than a bad sensor, it could be a loose connection somewhere. It reads 0 when grounded (0 ohms) and max at 90 ohms. An open circuit would make it peg.

My oil pressure gauge pegs also, sometimes after running for about 5 minutes it will look like its running okay. Sometimes it stays pegged.I've check oil & Oil is okay & I don't get the light. I plan on checking all connections when it gets warm (I don't have a garage to work in).

I have a problem with my oil gauge too. It dances around all over the place when I'm in neutral or with the clutch pushed in. I don't really notice it when I'm cruising, but as soon as I slow down and push in the clutch pedal, it starts dancing and shaking like Shakira
Is this a bad sending unit? Where do I get another one (that works)?

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-Adam
sqoach@yahoo.com

86 SE V6 - daily driver

Yea, my 86 SE is having problems too. It goes all the way down, the light comes on, and the buzzer goes off, when I make hard left turns. Any left turn at all causes it to drop a bit.

Thweny,

It sounds like your engine may really be starving for oil instead of just having a gauge problem. First, make sure your oil is full. Don't just trust the stick, how much do you put in when you change it? My V6 holds about 4.5 quarts, is yours a V6 or 4?

I have seen a V6 engine have the symptoms you described because the oil pump pick up tube/screen fell out of the oil pump (It's just pressed in, no bolts). The pump sits deep enough in the pan to still pick up oil most of the time, but sucks air on a hard left. The only way to tell for sure would be to pull the oil pan.

Meanwhile, take it easy on the left turns, running an engine with 0 oil pressure, even for a short period, is not good for it.

David.

[This message has been edited by DRH (edited 01-12-2002).]

quote Originally posted by Thweny: Yea, my 86 SE is having problems too. It goes all the way down, the light comes on, and the buzzer goes off, when I make hard left turns. Any left turn at all causes it to drop a bit.

That would make sense on a V6 if you're low on oil, because the oil pump is on the driver's side of the engine, and left hand turns cause the oil to move away from the pump. Shouldn't be a problem, though, if you have enough oil. I've noticed it on my Formula, and every time I've been about a quart low on oil.

Thanks guys for taking the time to respond. I don't think it's a low oil level. I just got the oil changed at PennzOil in December. I had the exact same problem before I got it changed. I'm looking at the receipt, it looks like they put 4.25 quarts of 5/30 oil. The dipstick level looks good too. Um, I don't know much about cars, but I was almost sure it was a gauge problem. If it could be anything else please throw out any ideas. The last thing I want to do is drive my car with no oil pressure.

You definitely don't want to oil-starve your 2.8. They really hate it when that happens.
Every 2.8 I've driven would occasionally drop to zero on left turns, if the oil was low. Take it easy on left turns until you get it fixed. I'm not sure how much oil you can add to repair the symptom. If you add too much, the crank will whip it into foam. Not a good thing, either.

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Raydar

From the Department of Redundancy Department.