Hydro Lock no oil pressure

[gerhart]

I have an 87 Bronco ii we are resurrecting. When we put the engine in and tried to start it, it hydrolocked due what we eventually found was a fault in the ECU. That fault caused the injectors in cylinders 3 and 6 to go wide open and flood the cylinder with fuel. We replaced the ECU and it not starts. We've let it run for a few seconds and the check oil light stays on so we shut it off. We don't think we are getting oil pressure. We hooked a oil pressure gage in place of the oil pressure sensor and no reading of pressure with the engine running 30 seconds. We dismanteled an old distributor and installed it so it engages the oil pump shaft. When we turn it by hand we get resistance after a partial turn. When I hook up a drill to it indefinitly labors as the number of revolutions increases so it seems like the pump is engaged. We are wondering if the gas associated with the hydrolock draining in the pan could have created some blockage of some kind. The oil pump was working fine when the engine was removed and dismanteled. Only the oil pan seal was replaced. The pump, shaft, etc were left intact. Anybody have any idea what this might be?

 

[RonD]

Did you get oil pressure with drill turning?

No, hydro lock will only bend connecting rods and break pistons.

Oil pressure is actually "back pressure"
The oil pump creates a flow of oil but there will be no pressure unless there is more oil than can be forced out the bearing gaps, when there is too much oil flow that's when you get oil pressure at the sending unit/gauge.
That's why 5psi of oil pressure is fine, any oil pressure means there is "too much oil" in the system so you have back pressure.
If there is a leak in the oil passages then there is not "too much oil", so little or no pressure is seen.

Without engine turning and with drill turning pump you should have seen oil pressure.
Also remove the oil filter put a pan under opening and turn the oil pump with drill.
Should flow out nicely.

 

[BRUTUS_T_HOG]

If you didn't change the oil after hydro locking I'm betting the oil is diluted with fuel

 

[gerhart]

We're baffled. Pulled the filter last night and its full of oil. Pulled the oil sensor switch and ran the drill at pretty good rpm and saw nothing come out the sensor hole.

Here is some additional history authored by my buddy who is helping me.

The 1987 Ford Bronco II with the 2.9 fuel injected 6-cylinder died while warming/idling five years ago. When the engine wouldn't turn over with the starter the spark plugs were removed. The number 6 cylinder was hydro-locked and thus the starter would not crank the engine. The engine was remove and stored. The injector, intake manifold and heads were likewise removed.
I recently acquired the Bronco, replace the heads with newer 1988 heads, installed new hydraulic lifters and reinstalled the intake, injector, accessories and installed the engine. Unaware of the previously hydro-lock issue I attempted to start the engine. The starter would not crank the engine. I remove the spark plugs and the number 3 and number 6 cylinders were gas hydro-locked. Realizing I had two injectors stuck open I replaced all 6 injectors. The engine still hydro-locked on cylinders 3 and 6. I then replaced the ECU and the engine cranked, started and ran. The issue now is the engine doesn't have any oil pressure. I pulled the distributor to insure that the distributor is engaging and turning the oil pump and yes that appears to be working correctly. When the pump is turned clockwise the proper direction by hand it gets harder with a revolution appearing to be operating correctly. I have never experienced a gas hydro-lock engine and I am now wondering if the hydro-lock could have plugged a line or something thus causing the oil pressure issue. My understanding is that the engine did not have an oil pressure issue five years ago when the first hydro-lock occurred. I certainly would appreciate any and all help with the no oil pressure issue.
Thank You

 

[gerhart]

When I replaced the ECU (which did fix the hydrolock issue) I changed the oil as well. Hoping the ECU was the fix and I didn't want to start the engine with the gas diluted oil.

Thx

 

[RonD]

Drill would need to rotate the same direction as distributor.

Not sure how the oil filter could be full if pump wasn't working, so I would assume filter mount is blocking flow to main passage, or new filter is blocking oil flowing out.

 

[Rowdy Fitzgerald]

This is a stretch but how was the block stored? Here where I live if you leave something like a block in a shed un covered, in 2 months mud dobber wasps will start filling holes with mud nests. I've had to clean several nests out of my truck's exhaust, door jams etc after being gone at work for week or two.

 

[gerhart]

You are absolutely correct. If you rotate the distributor counter clockwise ... no resistance at all. I am rotating the distributor clockwise with the drill. I'm going to pull the mount tomorrow to see if the gasket between the mount and the block could be blocking oil flow out from the filter. Filter is new but I have a new Wix filter I can try as well.

 

[gerhart]

Thanks for all who replied to my post. Checking the oil filter adapter was a great tip. Mystery solved. There was a small piece of plastic caught in the port heading out of the filter going into the block that was impeding oil flow. Once that was removed oil pressure is so it should be.

 

[RonD]

Glad you got it fixed, good work