I did a search already and cant really find anything that has the exact problems as my truck. I've got an 86 <a href="http://motorhaven.autoanything.com/">302 </a>5.0L with 69,000 miles i just put in my truck because my old one had bad rings. My problem is whenever the engine warms up and i come to a stop, the oil pressure gauge pegs at zero pressure and the engine starts to shudder like it wants to die. The RPM's stay at a consistant idle at about 1000. Also periodically after i shut the truck off and wait about 30 minutes start it again it will not stay running unless i hold my foot on the gas, keep it moving and then about two blocks later it will be fine. Pulled the codes, led to EGR, replaced that and still have the issue. Truck has new EGR, plugs, wires, cap, rotor, all new gaskets. I have checked for vacuum leaks as well as adjusted the timing. Any ideas? Are my stalling issue and the oil pressure issue somehow related? IAC, fuel pressure regulater?

 

According to everything ive seen on here about the Fuel Press Reg,you can pull the vac line off of it ,if gas spurts out its bad.When mine went out i had lots of gas in my oil.I could smell it strong on my dipstick.So if your fpr is bad you,ll also need to change the oil.

 

I hope this replacement engine was checked out before you dropped it in. If the oil pressure truly is zero, your main bearings, etc, aren't gonna like it. Put a manual gauge on that motor to verify what your oil pressure actually is. If the oil pressure is good , then procede with other diagnosing. If the pressure is really low, or zero, you might be on the verger of frying your engine. What I mean is, your crankshaft main bearings or piston rod bearings will probably sieze from being deprived of proper oil pressure. a Hope this helps.

 

you could actually spin a bearing and tear the block up pretty bad if it actually is at 0, I wouldn't run it any longer than absolutely neccesary,

 

I dont know forsure that it is at zero, i'm just going by the gauge which pegs zero when i come to a stop. I'll try a manual gauge and post my oil pressure results.

 

Does anyone know if the <a href="http://www.motorhaven.com/">302 </a>engine will shut down if oil pressure gets to low? I am guessing not but wanted to find out forsure...

 

One more quick question can anyone tell me what psi i should have for compression? I am going to run a compression check on it and would like to know what is good and what is bad compression. Thanks again!

 

I think somewhere between 90 and 120 PSI, but the lowest cylinder should be at least 75% of the higest, IE. if your highest psi is 100 the other should be at least 75 psi.

 

This sounds like a dumb question but do you have enough oil in the engine? Another way to test the Fuel Pressure regulator, turn the key to the on position, turn the key off. Press down on the shrader valve on the fuel rail about 5 minutes later. If gas doesn't come out your FPR is going bad. You should maintain fuel pressure in the fuel rail for about 30-40 minutes. Also, check the connector on the oil sending unit, mine came loose. At an idle it appeared good, when driving it varied from 0-normal. Hope this helps.