Been watching this site for a while, but first time posting a question.

My riddle: What is the cause of my lack of oil pressure and contant knock. 1991 2.3/5 spd combo. 150,000 miles. Ran great. Good oil pressure. Then I changed the oil last November.

The clues: Began draining oil, went in to have lunch. Came back out 30 minutes later, half-filled new FL-1A filter, spin on, plug back in pan, added remaining partial quart of Kendall 5w30 and four others via fill hole atop valve cover.

Waited 5 more minutes for oil to make it to pan. Started truck. Got the usual knock of lacking oil pressure as the system pressurized. This usually takes about 5 seconds. Then 10 passed then 15. Nothing registered on the idiot pressure gauge.

I shut down engine. Waited 2 minutes. Checked oil fill via dipstick. Yep, full to mark.

Attempted a restart. Gave it 30 seconds. solid knock from within engine. Shut it down and started scratching my ... head ... yeah.

OK, pressure sender unit is dead, I thought. Got new one. Nope. still knocking. Got a new mechanical pressure gauge. Pulled pressure sender, replaced with gauge line up in to cab to monitor from seat. Start it up ... knocking .... no pressure shows at idle.

OK, I give it some rpm to determine if the pump is weak or gone. 3,000 nothing. 4,000 gauge wiggles. 5,000 it Moves up about to 5 psi. Shut it down.

OK. now if the oil pump is failed ... it's failed right? This happened instantly and WHILE THE ENGINE WAS NOT RUNNING.

Anyone have a clue as to this problem. I just parked my baby and started driving vehicle No. 2. Now I'm finally getting back to figuring out this problem and wanting to fix it. Truck sat for 8 months. I started it up today and it's still knocking and showing no pressure.

Help me fix this great little truck, please.

Jeff

 

Pick up tube may have come loose causing the pump to suck air. Pump may have just lost prime, that has happened on rare ocasions. Any way sounds like you are sucking air instead of oil.

 

stick a fork in it, sounds like she's done, unfortunately...
pull the oil pan and check the rod bearings...

SteveL

 

Yeah, it's sucking something. ... I'm gonna drain the oil, refill the new oil filter and engine with heavier weight and – give me some input on this Ford fans – reverse prime the pump by inserting some tube in the oil feed hole at the filter boss and drizzling in as much as will go before remounting the filled oil filter Any thoughts?

Jeff F.
91 Ranger 2.3 ... no oil pressure

 

Get a oil pump priming shaft from a parts store, or an old distributer for that engine and take it apart for the shaft. Take your dist. out and insert the shaft and use a drill to spin it, this will prime the engine if the oil pump is still good.

 

Maybe you should get another oil filter. That is the only 'mechanical' thing that was changed... It could have an internal blockage that stops the oil from flowing thru it. That would have been my first guess. Other than that, there is a problem for certain years with the pan gasket material chunking loose inside the pan, and clogging the oil pickup. Someone on this site developed a technique using a coat hanger thru the drain hole to scrape the bottom of the pump pickup.
tom

 

Thanks for the thoughts. ... Mr F150, distributor, what distributor? I'm blessed with the dual coil pack ignition on this little honey. (This would work I expect on an older Ford though). Yeah ... I'm gonna use a new filter, though I've never had a Motorcraft one be bad before ... Hmmmm, scraping the oil pickup with a bent coat hanger ... might just give that a shot while the oils out ... Thanks all.


Jeff

 

Yes, I agree, try another oil filter....

 

I did not relize that they went distribitorless already in 91, my Mistake
Dan

 

what weight oil are you using

 

Thanks for the responses. I finally got to make another try at fixing my 91 Ranger. (2.3/5 spd). No oil pressure on a running engine.

1) I drained oil, pulled off old filter and it was empty.

2) I bent a portion of wire and poked around through the oil drain plug hole until I was able to scratch across the screen on the oil pickup, I moved around enough to hear that there is at least a portion (if not all) that is clear of debris.

3) I got a turkey baster and a length of tubing to insert into the oil feed hole in the block and reverse primed the oil pump from the filter side. It held oil without leaking down.

4) I filled new Motorcraft FL1A filter with oil to the brim, let is set and soak in and then topped it off again before installed back onto block.

5) Plug back in pan and 4.5 quarts of 10W40 into the engine.

6) So the review. Oil in engine, oil in filter. primed pump from back.

7) said a prayer and hit the ignition. Turns over fast and catches, watch the mechanical oil gauge do zip. 5 seconds, 10 seconds, 15 seconds. nothin.

engine is knocking on the bottom, so I turn it off.

After scratching my head I check my manual for the drive mechanism on distributorless 2.3s. There is a oil drive shaft and housing that sits in the old distributor hole. The shaft comes all the way through and you can see the tip if you remove a little rubber boot. So I grab a pair of vise grips and get a grab on it's stubby little head and try to turn it. There is the slightest amount of play it goes clunk to clunk in just a millimeter or two swing of the grips. So it IS still engaged with something (camshaft?).

What exactly drives the oil pump on an Overhead Cam engine?

Still looking for help. Thanks all.

Jeff

 

There is a shaft that used to drive the dist... & pump. It now drives the pump only. I'd suspect that you have something wrong. heh. Take out all the sparkplugs(at least 4 if you have a dual plug system), take off the cover that you removed to attempt to turn the pump drive shaft. Using a screwdriver, jump the small wire on the solenoid to the positive (red or battery side) big terminal. Be prepared for spark and the engine turning over. It should turn easily, and should rotate the shaft in question. If not, the pump will not pump. Viola. At least you'll know if the shaft turns.. There should be a 'dummy' distributor plug to hold the top end of the pump shaft, and it would be rather large compared to the pump shaft, as it would have a driven gear to mesh with the dist drive shaft turned by the timing belt...
tom

 

Thanks Tom W., I'll do a visual check on that as soon as the #$@% sleet stops falling here in Northern Ill. (might not be til spring methinks). I'm kinda resigned at this point to pulling the wee little motor out in favor of a 302 I'm putting together in the garage. no replacement for displacement and it's done its duty for 150K. jf

 

that happened to mine. i have a 89 2.3l dual plud dis. at about the same milage as yours mine started to lose pressure.may just be a fluke you was changing oil. the oil pan gasket came loose and plugged the oil pickup tube.i pulled the oil pan and replaced the oil pump ,the shaft , gasket and pickup tube and i have more oil pressure than ever before. i never replaced the bearings. mine never knocked but the top end rattled bad.no im at 253,000 and the same thing is happening again. so i will pull it down again.i have seen three of the 2.3 do the same thing besides mine.