92 Grand Marquis, no oil pressure

My aunt just bought this car and it has the 4.6 liter OHC V8. 2 days after we bought it it started stalling on her, i had ran a little rough before that. Then we were nursing it back to town and when she
slowed down for a stop sign it died (siezed?). The battery cables were ugly and it wouldnt crack so I replaced them, it cranked, made a loud pop noise, then started. It runs like crap and the oil pressure light is on, even when rpms are elevatred so we shut it down and towed it. Obviously something broke. Are there balance shafts in this motor? I had a mitsubish snap a balnce shaft and loose oil pressure the same way once. I havent played with fords in years, Any help is appreciated.
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On 16 May 2005 12:35:38 -0400, jshanab

No balance shaft and the oil pump is direct driven by the crank. If it ran more than a half minute or so with the oil light on, and now, will not turn over, it is probably toast.
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"jshanab" wrote: > My aunt just bought this car and it has the 4.6 liter OHC V8. > 2 days after we bought it it started stalling on her, i had > ran a little rough before that. Then we were nursing it back > to town and when she slowed down for a stop sign it died > (siezed?). The battery cables were ugly and it wouldn't crack > so I replaced them, it cranked, made a loud pop noise, then > started. It runs like crap and the oil pressure light is on, > even when rpms are elevatred so we shut it down and towed it. > Obviously something broke. Are there balance shafts in this > motor? I had a mitsubish snap a balnce shaft and loose oil > pressure the same way once. > I haven't played with fords in years, Any help is > appreciated.
It ran less than a minute with oil pressure light on, I shut it off. So it may be salvageable, How hard is it to change the oil pump, it must be what siezed and broke
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jshanab wrote:

You said you started it after it possibly "seized." You had elevated RPM's before you "shut it down." I'd do more investigating before holding a wake. Lack of oil pressure wouldn't make it "run rough." Will it turn over at all? If not by starter, by hand?
Frank
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"F.H.6" wrote: > jshanab wrote: > > "jshanab" wrote: > &nbsp;> > My aunt just bought this car and it has the 4.6 > liter OHC V8. > &nbsp;> > 2 days after we bought it it started stalling on > her, i had > &nbsp;> > ran a little rough before that. Then we were > nursing it back > &nbsp;> > to town and when she slowed down for a stop sign it > died > &nbsp;> > (siezed?). The battery cables were ugly and it > wouldn't crack > &nbsp;> > so I replaced them, it cranked, made a loud pop > noise, then > &nbsp;> > started. It runs like crap and the oil pressure > light is on, > &nbsp;> > even when rpms are elevatred so we shut it down and > towed it. > &nbsp;> > Obviously something broke. Are there balance > shafts in this > &nbsp;> > motor? I had a mitsubish snap a balnce shaft and > loose oil > &nbsp;> > pressure the same way once. > &nbsp;> > I haven't played with fords in years, Any help > is > &nbsp;> > appreciated. > > > > It ran less than a minute with oil pressure light on, I shut > it off. > > So it may be salvageable, How hard is it to change the oil > pump, it > > must be what siezed and broke > > You said you started it after it possibly "seized." You had > elevated > RPM's before you "shut it down." I'd do more investigating > before > holding a wake. Lack of oil pressure wouldn't make it "run > rough." > Will it turn over at all? If not by starter, by hand? > > Frank
Ok, i thought maybe flat lifters could make it run rough. I wonder if one of the fuel injectors got stuck and I hydrauliced a piston, breaking something when it turned over.
but there is no oil pressure after that loud pop, I guess the oil pump could of siezed?, cause the hard start the subsequent pop. roughnes is probably bad compression in more than one cylinder. Maybe pull the valve covers and the oil pan and do a compression test if all looks ok visually.
How about this scenario, low oil pressure first caused a siezed component in the valve train (wonder what this Overhead cam head looks like ) then a broken lifter or cam bearing allows it to spin again and the loss of compression on that cylinder makes it run rough and blows back into the intake and makes the adjacent cyliners run rough too.
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jshanab wrote:

First thing I would do is check the oil level, then remove the plugs and see if it turns over. If it turns over, check the compression. If it's got compression and oil, I would try to find out why no oil pressure. If you can get oil pressure and compression the rest is fuel and ignition trouble shooting. I wouldn't start dismantling the engine until I was sure I had to.
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"F.H.6" wrote: > jshanab wrote: > > > Ok, i thought maybe flat lifters could make it run rough. I > wonder if > > one of the fuel injectors got stuck and I hydrauliced a > piston, > > breaking something when it turned over. > > > > but there is no oil pressure after that loud pop, I guess > the oil pump > > could of siezed?, cause the hard start the subsequent pop. > roughnes is > > probably bad compression in more than one cylinder. Maybe > pull the > > valve covers and the oil pan and do a compression test if > all looks ok > > visually. > > > > How about this scenario, low oil pressure first caused a > siezed > > component in the valve train (wonder what this Overhead cam > head looks > > like ) then a broken lifter or cam bearing allows it to > spin again > > and the loss of compression on that cylinder makes it run > rough and > > blows back into the intake and makes the adjacent cyliners > run rough > > too. > > First thing I would do is check the oil level, then remove the > plugs and > see if it turns over. If it turns over, check the > compression. If it's > got compression and oil, I would try to find out why no oil > pressure. > If you can get oil pressure and compression the rest is fuel > and > ignition trouble shooting. I wouldn't start dismantling the > engine > until I was sure I had to.
Right, I will do that this next weekend, Just trying to find out as much info as I can. Trust me when i say something did break. pulling fully charged battery down to 8 volts and dimming all lights and crank slow- then a loud muffled pop, then jump up to 11 volts and it spun fast and started and suddenly no oil pressure.
Is this an old converted block with a oil pump driven off the old distributer mounting hole and a dummy distributer shaft like some GM products?
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"jshanab" wrote: > Right, I will do that this next weekend, Just trying to find > out as much info as I can. Trust me when i say something did > break. pulling fully charged battery down to 8 volts and > dimming all lights and crank slow- then a loud muffled pop, > then jump up to 11 volts and it spun fast and started and > suddenly no oil pressure. > > Is this an old converted block with a oil pump driven off the > old distributer mounting hole and a dummy distributer shaft > like some GM products?
A wild thought : I am looking at the wrong thing If this thing has a locking torque converter and it was getting stuck so it caused a stall and a hard start condition while in park. The pop was the torqu converter jumping and the low oil pressure, (Idiot light no gauge yet) is caused by a low engin RPM from the drag.
I wasnt gonna push it until I got a gauge and tried cranking it without pluts in it
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"jshanab" wrote: > A wild thought : I am looking at the wrong thing > > If this thing has a locking torque converter and it was > getting stuck so it caused a stall and a hard start condition > while in park. The pop was the torqu converter jumping and the > low oil pressure, (Idiot light no gauge yet) is caused by a > low engin RPM from the drag. > > I wasn't gonna push it until I got a gauge and tried cranking > it without pluts in it
Thanks lugnut, That information is very helpful. It sounds like a basic 2 valve overhead cam engine, I assume it is a non interference engine with the caveote that rotation direction is observed.
I had another thought: sheared a cam key or jumped a tooth, that would explain the rough idle on restart. Perhaps it got far enough off to hit a piston with a valve. Anyway a compression test will tell. and a quick look at the valve train with the valve covers off wil give me a good indication of the valve system operation. THe POP I heard was load and solid enough to have snapped part of a camshaft off, ahhh, speculation. It was running bad enough on restart to be running on one bank.
I am gonna consider myself a little above average on the DIY scale. I have built, rebuilt and changed engines and transmissions a few times in my life and have access to a machine shop at work. Not your normal automotive machine shop, but I can make anything. I should be able to re-time such an engine in my sleep. But I need a book! Do you know of any on-line resources?
humm, it has 174,000 miles and it was full of oil after first low rpm stall and second stall on way home and it had oil in it then also, (first thing I checked) But I am gonna check again. Thanks again for all your help.
you said the oil pump is around the crank, so no little shaft and worm gear? are we talking a spinning gear pump trapped betwen the motor and front cover driven by the crank? Man I need a drawing. got any pictures?
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jshanab wrote:

snipped for space / / / / /
Please let us know with the same subject line how this project progresses. Got me really curious now. :)
Frank
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F.H. wrote:

Me too. I can't say I've seen a 4.6 fail catastrophically unless it was badly abused.
Check out Ebay for a set of manuals for your car, they aren't expensive and are worth their weight in gold. For your 92, you should be able to find the shop manuals on CD for about $10. Paper will usually be more.
        Good luck, Tom
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"Tom Adkins" wrote: > F.H. wrote: > > > > Please let us know with the same subject line how this > project > > progresses. Got me really curious now. :) > > > > Frank > > Me too. I can't say I've seen a 4.6 fail catastrophically > unless it was badly abused. > > Check out Ebay for a set of manuals for your car, they > aren't expensive and are > worth their weight in gold. For your 92, you should be able to > find the shop manuals > on CD for about $10. Paper will usually be more. > > &nbsp;        Good luck, Tom
Ok I got a manual and have been trying for hours to get the darn fan off. what is the trick? the motor turns pretty freely, i am now thinking that the car jumped time back and forth, but I just want to get it apart for visual inspection, but man o man it wont budge
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"jshanab" wrote: > Ok I got a manual and have been trying for hours to get the > darn fan off. what is the trick? the motor turns pretty > freely, i am now thinking that the car jumped time back and > forth, but I just want to get it apart for visual inspection, > but man o man it won't budge
Not possible. Had to remove fan bolts and cut shroud. What a piece of @#$#. How can they give you a torque value on the fan clutch extension when the shaft is on bearings and the belt cant hold it tight enough to break it free or torque it during assemply. I smell special spanner tool that uses 2 of the pully bolts?
Now I am trying to get the valve covers off, but the bolts on the end are really hard to get to. The manual I got off of ebay is on CD and I am beginning to thing it is not from ford, they couldnt have such crappy manuals. Is there a trick, like unbolting motor mounts and sliding motor forward? or something to allow access to bolts?
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jshanab wrote:

http://www.parts.com/schematics/images/mechanical/FVP040.gif
Part #33 in diagram...
Rob
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On 16 May 2005 15:35:43 -0400, jshanab

The oil pump is mounted at the front of the crank. It fits around and is driven by the nose of the crank. Changing it is a bitch for DIY'er because you have to remove the timing chain which means you have to retime the cams. The engine does not have "lifters" per se. It has hydraulic lash adjusters installed under one end of the cam follower. The cam followers have been known to become dislodged in the event of low oil pressure causing a dead cylinder and, possibly, other malfunctions. If you haven't played with Fords for years, you should be aware that the 4.6L V8 is different from anything that came before it from FOMOCO. At the very least, you need to get a manual of some sort to see what your are letting yourself in for. You may need a special tool here and there if you intend to go into it. These engines require care and skill to do internal repairs. An intermediate DIY'er with a good collection of tools should be able to do the job with time and patience.
Before you even think about going into it, you should determine whether it is seized or hydraulic locked. Make sure it has plenty of oil in it. These engines are not prone to head gasket failures and an injector allowing that much fuel thru is a long shot. You need to pull the plugs and see if it can be turned by hand. On that year, I believe you can turn the engine with a large wrench on the fan hub. Be sure you turn it the normal direction of engine rotation. If it can be easily turned thru several rotations (at least 2 complete) by hand, the starter should be able to handle it. If you see water or fuel discharged from any cylinder, you are in for real work. If the starter is OK, run a compression check with the throttle blocked open and the coils disconnected.
Also, you should be aware that these early engine were prone to valve seal failure causing them to burn copious amount of oil without even smoking. I bought a "94 at 67K miles. It use a quart every 150 miles or about 2 qts per tank of gas. Were I not in the habit of checking oil frequently ( a leftover from my days of youth when a qt every 500 miles was normal and not smoking too bad was good to go), it would have been easy for it to run out of oil and seize.
Lastly, if the engine appears to be shot, it will not likely be financially feasible to rebuild it unless you just want to do it. The cost of a rebuilt is more the that vintage is worth. A good salvage engine is the best option. You local salvege yard will have a Hollanders manual to list which vehicle have useable engines. There are several versions that are not interchangeable without other modifications.
Good luck Lugnut
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