Failing Oil Pump, I think

[minigts]

Without going into an entire list of things I think could be wrong, is there any thought as to why my oil pressure gauge would start fluttering and get DANGEROUSLY low and then go back to normal as if nothing was wrong? It did this a few months ago, but I realized I had the sensor wires for the temp gauge and the oil pressure gauge and switch backwards (this came about at the 40 way bulk on a TII conversion on an L body). So I corrected this problem and the gauges started working fine and the fluttering seemed to go away.

Tonight, it got to the bar right at the "L", so I shut the car off WHILE driving and pulled to the side of the road. Because I have had this problem before I started it back up, it started fluttering about 1/4 of the gauge (on the low side) and stayed there, so I started limping home. My route takes me on an interstate so I took my route and watched the gauge being careful to shut down if it just dropped completely. By the time I had driven about 1-2 miles, it was back to normal pressure, just right of the middle and no glitches all the way home (roughly about 20 miles going 65 MPH).

Things that have consistent when this happened:

• initially, higher revs began to bring the pressure down but then the pressure starts to rise
• usually hovers at the 1/4 mark when gets to low, even above 2K RPM\
• idle does not fluctuate when the gauge flutters

I have considered:

• bad gauge
• bad wiring
• interference (electrical)
• bad pump
• something in the line from the pump (dirty filter)

I just changed the oil within a few hundred miles, so I'm ruling this out unless I have had random filters allow trash in the line or something.

Does anyone have any suggestions as to what is TYPICALLY wrong, if there is such a thing with these symptoms? I mean, my first assumption is a bad pump. I could try buying another sensor, but I'd rather risk a $100 or more on replacing the pump vs a $28 sensor and later a $2000 motor.

Any thoughts or suggestions are encouraged.

[tryingbe]

I don't see you mention mechanical oil pressure gauge anywhere..

[iangoround]

Get a mechanical gauge before you do anything else. It is entirely possible that the sensor is bad, the connection at the sensor is bad, or the gauge is bad.

Did the car make any noise when the pressure drops off? Normally the lifters are pretty quick to rattle without oil pressure.

[minigts]

Get a mechanical gauge before you do anything else. It is entirely possible that the sensor is bad, the connection at the sensor is bad, or the gauge is bad.

Did the car make any noise when the pressure drops off? Normally the lifters are pretty quick to rattle without oil pressure.

There wasn't any noise at all other than the ridiculous horse power being created by my motor. No seriously, there was no indication there was anything wrong with the car other than the gauge fluttering. And I had originally planned to get the mechanical gauge, but when I "corrected" the problem the first time, I refrained. This just happened last night, so I didn't get one as of yet. But the other thing I need to point out is that it doesn't happen all the time, so I could let the car sit and idle for an hour and it may not do anything, or I can drive it and it may not happen so that really wouldn't tell me anything if the fluttering is random. I mean I drove almost 20 miles RIGHT AFTER this happened and it didn't flutter at all.

But I plan on getting a mechanical gauge so I can check this. I didn't think about the lifters making the noise if the pressure truly dropped, which makes me feel somewhat better that it may not be the pump. I just don't want to lose my motor when I could have fixed it for $100 or thereabouts.

Assuming it is the sensor, any suggestion on where to get a reliable one? The dealer? I got this one at Napa.

Oh, I have another question while I'm thinking about it. I got the harness out of a Daytona, but my cluster is a Charger. Would this make ANY difference? Obviously it's been working fine, but that just struck me as something to think about.

[turbovanman²]

You can try a new sensor but until you hook up a real gauge, your just guessing. Go to any store and buy a cheap mechanical guage, just install it temporarilly and monitor the oil pressure, if its good, you can get a new OE sensor and leave it put the new guage in properly.

[minigts]

Not to get off subject, but what is the thing that is next to the oil pressure sender in this picture?


And btw, what took you so long to respond Simon?

[lametec]

Never mind..

[Turbodave]

Not to get off subject, but what is the thing that is next to the oil pressure sender in this picture?

Looks like a fitting for a braided oil line, probably going to the turbo.

[turbovanman²]

Not to get off subject, but what is the thing that is next to the oil pressure sender in this picture?


And btw, what took you so long to respond Simon?

That pic looks awfully familiar,

I had a little holiday, had stuff to do at home,

Thats for my oil line, I bought the fittings locally and use an Earls braided -4 line.

[minigts]

Well in my steps to begin installing the manual oil pressure gauge, I realized the factory sender was the culprit. It isn't too obvious from a top view, but after I removed it, you could see the plastic piece where the harness plugs in was coming apart from the base metal piece that threads into that little block. It wasn't broken, just separated. It had to have happened when I was installing it originally. I didn't have a socket to fit the sender so I used whatever I could and I more than likely pried it up just enough to stay on, but eventually start coming loose. But it fit back on, safely threaded and tightened back in place and no more issues.

Needless to say, problem solved! Thanks for the helpful suggestions!

[Dusty_Duster]

Glad you got it fixed.

I was going to suggest the gauge sender. Electric short-sweep gauges are notoriously inaccurate, especially towards the low and high ends of their range. (I say "short-sweep" because Autometer makes a line of "full-sweep" electric gauges that are microprocessor-controlled and self-calibrating. Those particular gauges are quite accurate, but quite expensive as well.)

[minigts]

Glad you got it fixed.

I was going to suggest the gauge sender. Electric short-sweep gauges are notoriously inaccurate, especially towards the low and high ends of their range. (I say "short-sweep" because Autometer makes a line of "full-sweep" electric gauges that are microprocessor-controlled and self-calibrating. Those particular gauges are quite accurate, but quite expensive as well.)

Well I have a set of the 2 1/8" pro-stock series? Or something like that. They are the sliver-faced gauges with orange needles and the bulb in the back. Doubt they are self calibrating, but I do prefer them over the factory cluster. Just need to get that stuff installed. So much to do and not enough fabrication time.

[minigts]

Ok, this problem has surfaced again, but I still think the sending unit is bad. Is there a brand out there anyone would recommend over another? I have the two wire plug-in type oil pressure sensor. I think I got the one I have from Auto Zone. Are they all the same? I have access to a mechanical gauge that I can hook up this weekend to confirm, but with the problems I had with this one I may just replace it.

So which would be the best to get?

[Juggy]

well u said u were installing a mech oil pressure guage......u need 2 seem them readings as opposed to the factory one...

id say its the sending unit, ive driven around with no oil pressure readings, kinda scary not knowing what is going on exactly, get that mech guage on there!

[minigts]

Well I can't do it until this weekend, but the main problem is it doesn't happen immediately. I mean I drove all the way to work, close to about 30 miles and it didn't do anything. I get about 5 minutes from work and all of a sudden it starts fluttering. So even if I get a mech gauge hooked up, there isn't any guarantee it will happen for a while. It's very intermittent, but did start back up again. Just really need to know if there is one brand over the other that is more reliable or made better or if they are all the same.

[Juggy]

when it comes to sensors, OEM are usually the best, but also usually cost more $$ unless you know someone who can get you the chryco discount!!!

prices on vendors sensors are fairly reasonable i will have to say

[turbovanman²]

I've honestly never had issues with aftermarket stock senders but you also can't go wrong with OEM.

I finally installed an Autometer electric guage as I wanted to know what was going on.

Does your valves start ticking when the oil pressure "flutters"?

[black86glhs]

Just do like the Government, shove a fist full of $$$$$ into the oil fill on the valve cover to take care of the "FAILING" item. It works for them.

[minigts]

I've honestly never had issues with aftermarket stock senders but you also can't go wrong with OEM.

I finally installed an Autometer electric guage as I wanted to know what was going on.

Does your valves start ticking when the oil pressure "flutters"?

No they don't, which is something I have been listening for as someone pointed this out earlier, maybe you. I certainly don't want to drive around with no oil pressure showing, but I'm not terribly worried. It would totally suck if it failed, but I think I would have time to shut it off, as I am paying VERY close attention to it and keeping the RPMs low.