I've already replaced one engine in this 89 ranger with another 2.9 Liter V6 because the first engine had a warped block witch kept breaking the head and me losin all oil pressure, now with the second engine in the truck the oil pressure has held above 0 but at idel, it runs at about 10-20 lbs and at higway speeds between 25-50 lbs, and when I let off the gas the pressure drops back down to 10-20 lbs, I was wondering if there was anyway to fix this problem with out having to put another damn engine in the :cussing: truck, thanks

maybe oil pressure sending unit is bad ? other guys would know better than me

Are you checking the oil pressure with an oil pressure gauge or are you looking at your dash gauge. Ford has a problem with oil pressure sending units going bad. If you don't hear the lifters rattling the oil pressure is fine.

Thanks guys that makes me feel better, but yes I am checking the Oil Pressure with a Oil Gauge from autozone...

I don't know off hand but maybe you could check a manual and see what it is supposed to run. I haven't ever had the need to check mine with a gauge but but my dash mount stays steady all the time the engine is running. I don't know if the 2.9s carry varible pressure pumps or not. If they don't, it looks like you got one anyway, hehe. Either way I don't think it will hurt anything.

Should be 20 at idle and above 40psi hot 2000rpm. The common cause is worn bearings due to coolant in the oil from cracked head(s) or clogged pump screen which can be back flushed to remove build up. The heads in these engines will crack if they are overheated, it is a good idea to put an explorer 4.0 auto rad in them with 180 stat. The 89 castings are better than the 86 ones, the after market heads are the best.

Well, the only thing the oil gauge seems to be good at doing is letting you know whether its got pressure or not. I had that happen in my truck. THe gauge never moved at all, until it lost the oil pump. The gauge definatly isnt the most accurate thing in the world.

After putting the manual gauge on it stayed alot more steady than the dash gauge did, but still at Idel it ran about 10-25psi and at throtle it ran 40-50psi, as long as it doesn't ever start Blowing out smoke and hit ZERO psi again I don't care what psi it reads, :rolleyes: