Which oil pump to use

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Pioneer Wagon

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I am a little confused as to when you would use the different oil pumps.
From what I can tell there are three.
1. Regular volume, regular pressure.
2. High volume. Regular pressure
3. High volume high pressure.
(Correct me please if these are wrong)

I have a mostly stock 2006 Yukon Denali. 6.0 liter with K&N Air intake, MSD 8.5mm plug wires, magna flow mufflers. So nothing special. Not trying to be a fat body Corvette.

I recently replaced the oil pick up o-ring, the oil bypass dumbell, oil pressure sensor(not the sensor screen though) . The radiator (mentioning this because this engine has the oil cooler lines running to it). All this was about 3k miles ago.
In the last 100 miles I'm having the oil pressure gauge jumping all over, and getting the "oil pressure low" signal at all levels of RPM.

I'm going to replace the sensor screen first. Then most likely going to redo the oil pick up tube, oring, and oil pump.
So I'm wondering which new oil pump to put in this engine.
Also...
I've seen a few guys add a washer to the oil pump bypass spring assembly to increase the pressure needed before the bypass kicks in.
Any thoughts on that little hack would be appreciated also.

Thanks guys.
 

iamdub

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I am a little confused as to when you would use the different oil pumps.
From what I can tell there are three.
1. Regular volume, regular pressure.
2. High volume. Regular pressure
3. High volume high pressure.
(Correct me please if these are wrong)

I have a mostly stock 2006 Yukon Denali. 6.0 liter with K&N Air intake, MSD 8.5mm plug wires, magna flow mufflers. So nothing special. Not trying to be a fat body Corvette.

I recently replaced the oil pick up o-ring, the oil bypass dumbell, oil pressure sensor(not the sensor screen though) . The radiator (mentioning this because this engine has the oil cooler lines running to it). All this was about 3k miles ago.
In the last 100 miles I'm having the oil pressure gauge jumping all over, and getting the "oil pressure low" signal at all levels of RPM.

I'm going to replace the sensor screen first. Then most likely going to redo the oil pick up tube, oring, and oil pump.
So I'm wondering which new oil pump to put in this engine.
Also...
I've seen a few guys add a washer to the oil pump bypass spring assembly to increase the pressure needed before the bypass kicks in.
Any thoughts on that little hack would be appreciated also.

Thanks guys.

I don't believe yours would have a screen under the sensor. AFAIK, that was a Gen4 thing on AFM engines.

It's possible your sensor is faulty or the plug is loose or damaged. The likelihood of the sensor being faulty is higher if it's aftermarket (even if it's AC Delco Professional/Gold or AC Delco Advantage/Silver).

If your actual oil pressure is fine, there's no reason to go with a higher pressure and/or higher volume pump. There will be no gain and it could actually cause problems from the unnecessary higher pressures on older seals. Not to mention excess load on the engine, reducing power output. If your actual oil pressure is low, it's due to an internal leak (such as a botched O-ring job) or worn bearings. Nothing will fix the latter other than rebuilding, but a higher volume of oil will make the pressure gauge read higher, giving you a warm, fuzzy feeling about it.

If all is well currently, just get a new stock replacement pump, AC Delco Original ("OE") or Melling.
 

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I don't believe yours would have a screen under the sensor. AFAIK, that was a Gen4 thing on AFM engines.

It's possible your sensor is faulty or the plug is loose or damaged. The likelihood of the sensor being faulty is higher if it's aftermarket (even if it's AC Delco Professional/Gold or AC Delco Advantage/Silver).

If your actual oil pressure is fine, there's no reason to go with a higher pressure and/or higher volume pump. There will be no gain and it could actually cause problems from the unnecessary higher pressures on older seals. Not to mention excess load on the engine, reducing power output. If your actual oil pressure is low, it's due to an internal leak (such as a botched O-ring job) or worn bearings. Nothing will fix the latter other than rebuilding, but a higher volume of oil will make the pressure gauge read higher, giving you a warm, fuzzy feeling about it.

If all is well currently, just get a new stock replacement pump, AC Delco Original ("OE") or Melling.

^^^ This. Totally agree. And if there's a screen under the sensor, someone added it but it's not necessary. Delete.
 

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One other thing that can happen is for the sensor to leak oil into the connector. Maybe rare, but be ready to clean the connector when you change the sensor.
 
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Pioneer Wagon

Pioneer Wagon

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One other thing that can happen is for the sensor to leak oil into the connector. Maybe rare, but be ready to clean the connector when you change the sensor.
Not sure what you mean. I thought the sensor pointed straight up, connection on top.
I could be wrong, just ask my wife......
But when I put the new one on it was pointed up.
I will definitely check and clean it though.

Is there a way to bench test the pressure sensor?
 

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The connector is on top, as you noted. But the seal inside the sensor can leak and oil pressure can push oil up into the electrical connection. I don't think it's all that common, but if it does happen, it will mess with the resistance in the connection.

I don't know of an easy way to bench test it.
 
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Pioneer Wagon

Pioneer Wagon

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The connector is on top, as you noted. But the seal inside the sensor can leak and oil pressure can push oil up into the electrical connection. I don't think it's all that common, but if it does happen, it will mess with the resistance in the connection.

I don't know of an easy way to bench test it.
Ok. Thank you.
I'll definitely check it. Might replace just because.
It is an AC Delco part. I thought I was avoiding cheap parts.
 

iamdub

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I wouldn't even bother trying to bench test it, mainly because it's intermittent. I'd first use a scan tool to see how the pressure that the PCM is seeing compares to what the gauge is reading to determine if you have a faulty gauge. If the PCM reports the same actions as the gauge, use a known accurate mechanical gauge and determine the actual pressure and if it holds steady. If so, then the problem is the sensor or its circuit.
 
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Pioneer Wagon

Pioneer Wagon

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Ok. I pulled the sensor and it looks clean. Of course that dont me squat.
I placed my finger in the hole and had my wife start it up for 2 seconds. It had enough pressure to blow oil past my finger.
So I have a replacement sensor on order, but I also want to test out the wires.
Does anyone have a diagram showing where the wires run and where they end up?
 

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