Ok this is the deal, My 1998 Explorer had 76,000 miles and the Timing chain tensioner the right side broke. So I pulled the engine and changed both left and right chains and guides as well as both hydraulic timing chain tensioners. Then I thought well I have the engine out I should replace the oil pump too. Put the engine back together and put it back in. Runs great and sounds awesome. Here is the bad part when I’m at a red light the oil pressure will drop to ZERO. When you give it gas it jumps right up. The engine will start to tap in the top end if you sit in gear for a few minutes at an idle. As I said before when you give it gas it quiets up and runs great. One more thing the left front tensioner came with a oil volume reduction plug to be put in the head, and the tensioner itself is a lot bigger then the old one. I’m not sure what to do. Do I have a bad pump? Or is there some other problem?

 

Do u have a repair manual that describes the pump installation procedure?

 

you dont happen to be using a fram oil filter do you??

 

No its not a fram its an Advance out brand.

 

NO I went by what was in the chilton's. Is there something I should have done?

 

Could this be a "dummy" oil pressure gauge problem? Look at this thread. https://www.ford-trucks.com/forums/s...mmy+oil+gauge+

 

Because you get a tapping when idling for a while, and because the pressure drops at an idle but jumps up when you rev the engine, I would say you have a problem with the oil pressure and it is not a problem with the gauge.

Unfortunately I cannot help where you are losing oil pressure, but you will have additional and excessive wear if you let the oil pressure drop too low for too long.

A leak at the oil pump will cause the problem.

Also, I think most cars have a by-pass valve that relieves high oil pressure. Your symptoms are the same when it sticks.

As to the plug and tensioner, I don't have any experience there. But if a plug is missing where one should be in the oil flow, you will get low oil pressure at low RPMs.