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Discussion Starter · #1 ·
Okay, so first and foremost, I'm not a mechanic. Most complex work I've probably done is rebuild a carburetor. I can change simple things like thermostat, radiator, alternator, battery, voltage regulator, that kind of thing, but I've never done anything like a head gasket or any engine disassembly, or anything that requires complex tools or sensors. Never adjusted timing even.

I have a D1VE engine block in a lifted 79 F100. Standard rebuild by Jasper probably about 8 years ago. (yep, out of warranty).
I only use it to move, help friends move, or if I'm picking up a load of dirt/mulch or home projects stuff.

It has the 3 aftermarket gages mounted under the dash, including oil pressure.
The oil pressure for a long time seemed to ready around 25psi most of the time, and up to maybe 50psi, but the gage was working.

I was driving it a few weeks ago, and the dash light came on for oil. From other forums, I thought someone said the light only comes on if it's below 5psi. Which, would be a problem if that was going down the road that way, and so people were recommending using the gage. I had an electric 'leak' at one point that the garage was able to find and fix, so that I can leave the battery connected. I'm guessing they disconnected the wire that went to the under dash gage, and connected to the dashboard light.

I brought the truck in to a shop that I have had pretty good luck with, felt like they're fair and not trying to just jerk me around.

This time, when I brought it in, thinking maybe it was a sensor or oil pump, or maybe just the wrong sensor had been installed before, they said they tried both kinds of sensors, and put a new oil pump and it's still reading no pressure. They said the volume is okay but there's no pressure to it.

They called Jasper and didn't really get anywhere from the technical folks there. The shop said they have had issues with Jasper engines in the past. They want to pull the engine, take it to a machine shop, have them check cam clearances and things like that. Which I'm guessing will cost thousands. Honestly I'm more likely to just drive it until it blows up before I'll dump thousands of dollars into an engine with only 3k miles on it.

I asked to make sure they were reading directly with a tool, and not just looking at the gage in the truck, and they said yes, and said they actually thought maybe their tester was going bad so they bought a brand new $800 tester just to be extra sure.

This engine has about 3000 miles on the rebuild. I've driven it 80-90mph on the highway, have helped a couple people move. I've never had an overheating problem, and when it idles even for a long period it doesn't seem to have any issue. Occasionally if it sit's for a while, then after driving it, it kicks white smoke out when I'm backing into my driveway. no idea what's going on there.

It has sat for a few months off and on, and it's parked outside.
It has a Holley carburetor on it with an Edelbrock intake.
It has brand new headers with dual exhaust.

I'd be really interested if anyone has had a similar issue and it ended up being something simple. Also, as far as a tester for the pressure, I don't mind buying a tool if someone can recommend one that is reliable, accurate enough, and a good value for having for personal use.

I'm just hoping there is something other than pulling the engine that will solve the problem.


Thanks!!
 

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You have described what your gauges are telling you, has your engine changed performance-wise?

I'll also ask the obvious, when was the last time the oil filter was replaced?

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You don't need any special tool.Go buy a cheap mechanical oil pressure gauge and install in the back of the block where the oil pressure sending unit is located.If still no pressure,with the new pump,oil is leaking out somewhere,probably bearings...or maybe the pickup tube is cracked. Find the problem or it WILL blow!
 

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Discussion Starter · #5 ·
You have described what your gauges are telling you, has your engine changed performance-wise?

I'll also ask the obvious, when was the last time the oil filter was replaced?

Sent from my SM-N950W using Tapatalk
Thanks for the response! I feel like there are a hundred threads talking about this issue, but everyone seems to have low pressure or have an inkling of the problem, instead of just 0 pressure with a decent running engine.

I can't tell any difference in the way it runs at all.

Oil ends up getting changed about every 500 miles since I don't drive it much. Changed the oil as soon as the oil light came on--saw a lot of posts where oil weight and off-brand filters were giving people headaches. I usually use one like Bosch or Purolator premium that show 99.9% efficiency, whatever that means (seems like OEM are more like 95%). Anyway, based on those posts, I put a Motorcraft filter on and went with heavier oil. I think I went with 20W-40 or something like that, but it's hard for me to believe 0 PSI would come from something simple like that.

Since my post, I did buy a mechanical gage. I hooked it up last night in the location behind the intake, and I let it idle until the temp was showing about 195 degrees. Revved it up a little--I don't have a tach but it sounded like maybe I went to 2000-3000RPM. Needle on the gage never budged.

I called Jasper who did the rebuild, and they said they put a brand new Melling M-84J oil pump in it. It seems odd that the oil pump would go bad after just a few years and less than 3k miles, but I don't know their history.

Also, people keep asking me if it's blowing blue smoke. On occasion, it has blown a bunch of smoke, after running errands, just as I'm putting it back in the driveway. I thought it was white smoke. Seems like that shouldn't happen on a nearly brand new engine. But I've also had this truck going 90 down the highway and the only problem I noticed was it burned gas at about 5mpg. But it's lifted with 35x12.50 tires so it's not exactly a Prius.

So here's my plan for my next steps, after looking at forums and YouTubes and talking to Jasper technical folks.
1) unhook the gage, leave the sensor hole open, crank the engine to confirm it spits oil. My mechanic said it's getting volume but no pressure. So I want to confirm what he's saying. That should mean the oil pump is at least functioning, even if not fully. Then I'll reinstall my gage.
2) take the distributor out--paint mark the orientation so I can reinstall it the same way--confirm no serious wear on the drive gear (whatever it's called) and also confirm I can see the shaft from the oil pump. New distributor if needed.
3) remove the oil pan, check the pickup tube gasket. (side note my pan is front sump--I can't do rear because it would interfere with the exhaust but the front of it is only about 3 inches from the steering rods, which I could probably hit if I used the full suspension travel. So if there is such a thing as a mid-sump that's what I probably need to find anyway. I might go ahead and replace the pickup tube and gasket. There was a big dent on the oil pan when I bought the truck so I wonder if there is a crack in the pickup tube or some damage. I'll clean it up and see if I can see anything wrong, but while I have everything open I may just go ahead and replace it.
4) remove the caps and see if I see any internal scoring or damage. I haven't been marking oil changes on a calendar or anything so I really couldn't say whether the longest the truck sat was 3 months or a year. It's always parked outside, so not sure how sensitive it would be to sitting for a long time outside in Kentucky. I figure if it has scratched up metal surfaces, that's where the pressure is going, so then I need to figure out what to do about oil pressure monitoring while I reluctantly save for a new engine. The mechanic did say everything looks shiny and new in the engine, so I'm hoping that he's referring to this same inspection.
5) remove the oil pump and re-prime it. sounds like this might just mean submerging it in oil, but I need to look this up. I figure if the mechanic was getting impatient maybe he missed this step or something, just might as well take that step. Is there a way to check for oil pump damage? I'll have to do some searches on that. I've heard some people put high pressure pumps in, but then others say that speeds up the wear of the distributor gear. Maybe if the internals are scored up and dropping pressure, I could just get a heavy duty distributor and a high pressure pump, a performance pickup tube, and hope by overcompensating on those items, it overcomes the pressure drop. Not sure if this ramrod idea would create worse problems though.
6) if the internals are scored up and I can't get a pressure reading at the current sensor location, I was thinking about putting an actual sensor in one of the other pickup locations, and running that to a second oil pressure gage. Then if it's actually showing pressure, I could monitor that for changes to know if my engine is about done.
7) new oil pan gasket, new pickup tube Oring/gasket.

I'm tempted to just do the distributor, oil pump, pickup tube, and gaskets/orings all myself, but I really don't want to if it's definitely not needed, and if I pick a junk brand then I could be making things worse still.
 

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Discussion Starter · #6 ·
You don't need any special tool.Go buy a cheap mechanical oil pressure gauge and install in the back of the block where the oil pressure sending unit is located. If still no pressure, with the new pump, oil is leaking out somewhere, probably bearings...or maybe the pickup tube is cracked. Find the problem or it WILL blow!

I got the mechanical oil pressure gauge and installed it in the back of the block, showing 0; needle won't budge. Other than some smoking occasionally, I haven't seen any leaks--driveway is dry, after weeks and months even. Pickup tube is definitely on my list to check, seems like that's a problem a lot of people run into.

Thanks!!
 

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Discussion Starter · #7 ·
Bad oil sending unit maybe. Some will not start without oil pressure to save engine from blowing up.
I wish that's all it was! I am showing 0psi idling at 195 degrees, but no crazy sounds coming from the engine. But I do plan on installing a T fitting with both the idiot light sensor and a sending unit, which will go to an under-dash gage, so I can have both working, just for fun. Hoping I can fix the pressure problem and make good use of that setup.

Thanks!
 

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1990 Ford Mustang LX 351M powered!! Project Cherry Bomb!!
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I'm along w checking that pickup tube, along w the gasket from the oil pump to the block. It could possibly even be the oil pump shaft from the distributor to the oil pump is partially stripped out and is catching just enough to spin the oil pump enough to oil the crank??You can also check it when you've got the distributor out by chucking up a 5/16 socket or an 8mm in your drill, (gnna need a long extension in the drill to do this) and spin up the oil pump and check the guages, check the back of the block where it plums in, and pull a rocker cover off and confirm that oil is making it to the top of the engine. You've gotta be getting some oil to it somewhere otherwise it would be making some expensive rattle rattle clunk whap! noises!! It may even be that the oil passageway to the back of the block is stopped up somehow?? That would show if you check it with the drill trick and the back of it uncorked? Just a few thoughts and my $0.02!! Cheers!!
 

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Discussion Starter · #9 ·
I'm along w checking that pickup tube, along w the gasket from the oil pump to the block. It could possibly even be the oil pump shaft from the distributor to the oil pump is partially stripped out and is catching just enough to spin the oil pump enough to oil the crank??You can also check it when you've got the distributor out by chucking up a 5/16 socket or an 8mm in your drill, (gnna need a long extension in the drill to do this) and spin up the oil pump and check the guages...

Thanks!
Just saw this. I have a few extensions, I could probably do that. I already put the distributor back, but it came out pretty quickly. I took some pictures of the oil pump shaft, and took a pretty good look at the distributor. Distributor gear looks really good, and I don't remember noticing any sort of marring on the hex hole. I could only see so much of the hex shaft, but I'm a little nervous about dropping a socket that deep, seems like I've read about there being a risk of knocking that shaft out of the coupler into the oil pan. One person I spoke to said you had to give it a pretty good shove to make that happen, but it sounded like a common thing to happen from some other posts. So ehhh..


check the back of the block where it plums in, and pull a rocker cover off and confirm that oil is making it to the top of the engine.
My beginner-mechanic brain is not registering what this means. But a quick google helped me understand that rocker cover and valve cover is the same thing, so by "confirm that oil is making it to the top of the engine". Can you elaborate on this? Do you mean, take the cover off, and spin the drill, to make sure oil spits out into the valve area? "where it plums in" is the part that's tripping me up on this part. I saw one video where they were showing some plug screws on the back of the block and if one was too deep or something it messed up the flow. But I would think if anything in the rebuild went wrong, I would have had problems before I went a couple thousand miles.


You've gotta be getting some oil to it somewhere otherwise it would be making some expensive rattle rattle clunk whap! noises!! It may even be that the oil passageway to the back of the block is stopped up somehow??
This is exactly my thoughts! I drove it probably at least a half hour after the dash oil light came on, drive it to the shop, drove it home from the shop. Dash light is off now, but they don't have it hooked up. I'm still waiting for my dummy switch to come in so I can do the T thing.


That would show if you check it with the drill trick and the back of it uncorked? Just a few thoughts and my $0.02!! Cheers!!
So by 'back of it uncorked' do you mean simply the sending unit removed and hole left open? I've seen where people say to do that to make sure oil comes out. My mechanic said that it was getting "volume but not pressure" so he was basically saying oil was flowing, but not enough pressure to even fill the tube to get a pressure reading. And when I hooked up a pretty basic mechanical gage, the needle never budged at all.

Thanks again!!
 

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Discussion Starter · #11 ·
Could the pressure relief valve in the pump be hung open?
Not sure--once I get the oil pan off, will this be pretty obvious to see? I've never actually taken an oil pan off this truck before (although it was off recently when the shop replaced the oil pump of course).
 

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Discussion Starter · #12 ·
Another question that ties into this. I'm going to see if I can find anything online that helps me on this, but trying to figure out if I can get this oil pan off without lifting the engine. It looks like if I take the starter off, and the oil filter off, I might be able to get it out, but I'm not sure how much the pickup tube and pump get in the way of that. The truck is lifted quite a bit, but still just not sure. It's 30 degrees out and I'm working in my driveway, so I'd rather not pull all those bolts out and weaken the seal just to find out I can't get it out.

To be clear, the oil catch pan is sitting on about a 12" tall box on the ground, so the darker pictures can be a little misleading. The exaust tube is a few inches down from the pan, and the steering rod closest point is about 3 inches on one side below the oil pan (another potential problem I need to look into later).


Thanks!!

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Sorry I didn't elaborate on what I was talking about, yes I was meaning if you took the oil pressure sensor or where the line goes in for the guage off then tried the drill trick you should have oil squirting out there unless there is a blockage in that passage. Before you take the oil sensor or guage loose you could try the drill to make sure that oil is getting up to the valve train by pulling one or both of the valve covers. When you spin it up you should see oil coming up thru the pushrods and dribbling down onto the rockers. I do this before cranking up a new engine or one that's been sitting for a long time. Case in point, I just cranked up a 351M that's in my 90 Mustang that's not been cranked up for 11 years. I'll post that elsewhere. Hope you find joy when you get the pan off and find what you're looking for!!
 
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