Oil Pressure Dropping To 0 Under 1500rpm-???

BKM48198 · Jun 6, 2014

jrichker said:
@BKM48198
I added a ground wire for the oil pressure sender, and it didn't change anything.

The next possible culprits are the wiring , dash connectors,and the anti-slosh/instrument voltage regulator module.

My gas gauge hasn't worked correctly for months, so I guess it's time to fix the spare anti-slosh/instrument voltage regulator module that been sitting on my electronics workbench for a very long time...

I also tried the ground wire and the oil pressure gauge still is dropping, I changed the fuel filter and it is idling a little better, I plan on getting some new vacuum hoses tomorrow and replacing all of them and getting a mechanical oil pressure gauge and trying it. While I'm at the store I will pick up some thicker oil and a filter and try changing them if the gauge doesn't take care of the problem. I live in Michigan and don't drive the car during the winter so I'm not too worried about the thicker oil.

MFE92 · Jun 7, 2014

BKM48198 said:
getting a mechanical oil pressure gauge and trying it.

For the love of god, do this before you do anything else.

BKM48198 · Jun 7, 2014

The first thing I will do today is drain the water from the cooling system and get an antifreeze mix in it, if it was going to leak I wanted it to be just water and not antifreeze, then I will replace the vacuum lines because I know they are old and probably leaking somewhere, then I will hook up the mechanical gauge.........I hope that is OK with God! I would have done this earlier in the week but I do work, have had relatives visiting, and other things in life are important also.........mostly my wife, she is diabetic, has MS, and after having a mole removed and a biopsy on it she found out she has the beginning stages of skin cancer. I love my Mustang but I love my wife more, that is why I haven't had time to get the oil pressure gauge already!

stykthyn · Jun 7, 2014

Don't muck with the coolant or vac lines. Just hook up a mechanical gauge and see what it says.

MFE92 · Jun 7, 2014

stykthyn said:
Don't muck with the coolant or vac lines. Just hook up a mechanical gauge and see what it says.

For 's sake already. It's like he has his head in the sand on purpose.

mikestang63 · Jun 7, 2014

No this could be just me, but you might think of getting a mechanical oil pressure gauge t0 verify the pressure. Wonder why no one else has mentioned it.

BKM48198 · Jun 7, 2014

stykthyn said:
Don't muck with the coolant or vac lines. Just hook up a mechanical gauge and see what it says.

Hooked up a gauge and it drops to about 5lbs at idle- (700-800) rpm, what next? Should I drop the pan and try my old pump and pickup, I should have another set of gaskets for both in the Fel-Pro set I bought so all it would cost is my time, it has a one piece pan gasket that hopefully would come off OK and be re-usable. It looks like if I was to unbolt the motor mounts I could probably raise it an inch or two with my cherry picker and have clearance to get the pump out, I REALLY don't want to pull the motor out completely if I don't have to. If this ends up being a lost cause I could always put the heads and intake on my old block and hope new gaskets would be all it needs, I think it had a head gasket that was starting to go, I was getting a little oil in my cooling system and a bit of smoke out the exhaust with the old motor.

I did notice that the EGR valve was sucking in right away, when I unhooked the vacuum line to it the car did idle better, less surging at idle. Should it suck in right away like that, I even swapped out the vacuum lines between it and the fuel with no changes.

Any thoughts or ideas would be appreciated.

stykthyn · Jun 7, 2014

You can change the pump without pulling the motor but it would be faster and easier to pull it. The pump could be suspect or your pump shaft may not be seated well.

MFE92 · Jun 7, 2014

If you end up dropping the pan, I would not do a thing to it until I pulled the main caps one at a time and had a look at the bearings, and if they look OK, plasti-gauge them to be sure. And while you're in there look to see if the block is cracked between the main bores and cam bores.

BKM48198 · Jun 7, 2014

stykthyn said:
You can change the pump without pulling the motor but it would be faster and easier to pull it. The pump could be suspect or your pump shaft may not be seated well.

Pulling the motor would be a lot bigger job, I think If I can just unbolt the 2 motor mount bolts and raise the motor I can get to all the pan bolts easily, there is some room already under the pan and I believe with just 2-3 inches the pan would drop enough to get to the pump and pick-up bolts, since I am doing all the work myself that would save a lot of time not having to install the AOD again.

stykthyn · Jun 7, 2014

I'm with mfe. Pull the motor and check the bearings. I've changed a pump and gasket with the engine in the car and trust me it's easier to pull it.

BKM48198 · Jun 7, 2014

MFE92 said:
If you end up dropping the pan, I would not do a thing to it until I pulled the main caps one at a time and had a look at the bearings, and if they look OK, plasti-gauge them to be sure. And while you're in there look to see if the block is cracked between the main bores and cam bores.

When I had it on the engine stand I looked it over and couldn't see any signs of cracks, I was looking closely because my OE motor did crack and snap the crank while blowing out the front of the block and pan. I don't know enough about the bearings to be able to tell if they were good or not, that is why I left the bottom end alone and only changed the cam. I know enough about engines to swap parts but not enough to tell good bearings from bad unless they have a wear pattern worn in them. This is a LOW budget build, funds are VERY limited due to my wife's medical problems.

mikestang63 · Jun 7, 2014

Trying to do an oil pump with the motor in the car is a PITA. You will also want to inspect the main and rod caps, so out comes the motor. You will be able to see if the bearing material is scored or damaged.

BKM48198 · Jun 7, 2014

mikestang63 said:
Trying to do an oil pump with the motor in the car is a PITA. You will also want to inspect the main and rod caps, so out comes the motor. You will be able to see if the bearing material is scored or damaged.

What exactly do I look for? Will the damage be visible to the naked eye? If it has to come out I will probably put a cover over the car and save up for another motor for next year, either that or put my parts on the old block and try it. The motor sounds good, and feels like it has more power than before......i was really ready to start driving it.

BKM48198 · Jun 7, 2014

MFE92 said:
For ****'s sake already. It's like he has his head in the sand on purpose.

It's really more like I have more time than money, and I haven't had much time lately. I did try an old gauge I had laying around but didn't really trust it, it showed about 12-15lbs at idle, the good gauges I have were smaller threads and I didn't have an adapter that would fit. I got paid yesterday and bought a gauge today, if you were paying the medical bills and for the prescriptions I am you might understand.....hopefully you never have to find out how it is.

MFE92 · Jun 7, 2014

It's not a matter of spending money for spending money's sake, it's a matter of not ing around with things that don't matter one single damn if you don't have oil pressure. No amount of vacuum lines and yada yada is going to make the engine run better if you don't have oil pressure, but you seemed to be in denial about that.

BKM48198 · Jun 7, 2014

It might not matter on this block but if the low vacuum is from a crack in the lower intake and I end up putting it on another block and waste money on the gaskets it would matter. The lower was drilled and tapped. I have been assuming the block will end up needing to be replaced since it first started dropping the pressure. I just want to find any and all problems with these parts before I spend money putting them on a different block. I put in the new oil pump and pick-up hoping to not have an oil pressure problem and I end up with one, which sucks. I feel like I wasted money on them trying to avoid a problem, now I don't know if the pump is bad or the engine is. After all the work that I put in it and it started up good then lost the pressure after heating up is a big let down. Since I have to do 100% of the work myself I want to eliminate any work I can.

stykthyn · Jun 8, 2014

Did you prime the pump after install?

BKM48198 · Jun 8, 2014

stykthyn said:
Did you prime the pump after install?

Yes, I used an old distributer that I removed the gear from to prime it, hooked my drill up to it and turned it backwards and checked the oil filter to make sure it had oil in it to be sure it primed good.

stykthyn · Jun 8, 2014

BKM48198 said:
Yes, I used an old distributer that I removed the gear from to prime it, hooked my drill up to it and turned it backwards and checked the oil filter to make sure it had oil in it to be sure it primed good.

2 possible scenarios. Bad pump out more likely the donor motor never had proper oil changes and suffered oil starvation killing the bearings. I've seen this on explorers before. Pull the motor and check the bearings. It will be easier abd cheaper than swapping heads.

Oil Pressure Dropping To 0 Under 1500rpm-???

BKM48198

MFE92

BKM48198

stykthyn

I want to measure mine. It doesn't look that tall.

MFE92

mikestang63

BKM48198

stykthyn

I want to measure mine. It doesn't look that tall.

MFE92

BKM48198

stykthyn

I want to measure mine. It doesn't look that tall.

BKM48198

mikestang63

BKM48198

BKM48198

MFE92

BKM48198

stykthyn

I want to measure mine. It doesn't look that tall.

BKM48198

stykthyn

I want to measure mine. It doesn't look that tall.

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