Oil pressure down to zero when idling.

PlymCrazy

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The oil level will never be higher than it is at idle. Therefore I dismiss the pick-up height being to high or level to low. Pressure is low at idle because the pump moves less volume at lower engine speed. Is the pressure really at zero? We don't know that without trying another gauge. I just helped a guy with a 390 Ford. Same issue. He swapped the gauge, problem solved. Thicker oil would only be the answer if oil temp is extremely high. I oubt that as well. So suppose it's not the gauge. You've swapped filter to a Wix. I would discount the filter as the issue. There is a possibility of the relief valve never closing all the way, though unlikely. Since it has pressure at speed I would also discount any galley plugs not seated or missing. There may be a lot of internal leakage, loose lifter bores, bearings. Or a rocker shaft loose? causing an internal leak inside the valve cover. If it passes all these tests I would put a high volume pump in it. But to be honest I'd bet it's the gauge.
Doug

Agree that's why I made the suggestion in post#2
This makes sense now. It sounded like the idle related issue was an iffy reference point because it was inconsistent. The sudden stop causing the symptom consistently is why I’d think the pickup was not submersed at the time. But the finer details you mentioned I hadn’t even accounted for. I’m learning here too.
 

gtxdana

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Step one-put a mechanical gauge on it to check.
Step two-put replace that failing Dakota Digital sender.
The Dakota Digital VHX gauges in two of my cars have a lifetime warranty and they've sent replacement senders for free.
 

dvw

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Bad on me. For some reason I never rear the last sentence in the original post. That adds another layer to the story. The drop on sharp brakings most definately caused by the pickup sucking air. Now you have a hemi pan which takes one more qt of oil. If it has the standard pickup it would be cofigured for the standard pan. So the pan to pickup could concievably be 2qts low in their relationship.
Doug
 

OzCharger69

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Bad on me. For some reason I never rear the last sentence in the original post. That adds another layer to the story. The drop on sharp brakings most definately caused by the pickup sucking air. Now you have a hemi pan which takes one more qt of oil. If it has the standard pickup it would be cofigured for the standard pan. So the pan to pickup could concievably be 2qts low in their relationship.
Doug
I think the money is right there. I'm low on oil. I ordered oil and filter next week and will see if that fixes the problem.
Step one-put a mechanical gauge on it to check.
Step two-put replace that failing Dakota Digital sender.
The Dakota Digital VHX gauges in two of my cars have a lifetime warranty and they've sent replacement senders for free.
I think the oil pressure readings are correct. The sender is from Summit, Dakota didn't supply a sender. The readings are accurate and measured against a mechanical sender. however I can never verify when it drops to zero at the lights because the car is in motion and by the time I get out of the car and pop the bonnet, the pressure starts climbing back up.
@OzCharger69 - are you running a windage tray inside the sump?
I wouldn't know, never took the intake off
 

kiwigtx

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Kiwi, is that also what some call a baffle in this application?
Ummmm.....maybe. This is what I call a windage tray......

1669407255575.png
 

BSB67

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I spoke to the previous owner and apparently it has a Hemi oil pan and a Hemi pickup as pictured. Could this be the issue?View attachment 1377207
This does not look like the Hemi pans I’ve seen. Maybe they are not all the same. Hemi pans have baffles to help prevent oil sloshing from the pick- up on both acceleration and deceleration. Even if the pick-up is wrong, or your 2 quarts low, you shouldn’t uncover the pick-p in a baffled pan on the street.

There is confusing and conflicting info in this thread. As others have stated. Get a mechanical gauge positioned in a place where you can read it at all times while driving.
 

OzCharger69

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UPDATE - problem solved

The issue was there wasn't enough oil in the engine. I add a quart of oil and the problem resolved completely. I did some hard braking and drove 20 miles.

The Lokar dipstick showed oil to the full mark before adding that quart. So I obviously have the wrong dipstick.

Thanks everyone for the input, it's good when the solution is simple and inexpensive.
 
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