Knock Knock Knock WTF?!?

[RussianBadBoyLB]

A buddy of mine got a 1991 corolla, that car been taken care of since day one. It has about 240,000 miles, yah I know its a lot but still ran very smooth and clean, and had no problem passing recent smog. Just last night it started knocking out of nowhere. He immediately pulled over and left it parked where it happened to prevent further damage. His dashboard light did not work, so he could not tell weather any lights came on.
Now I am not a toyota expert, I worked on fords before, so I have some knowledge, but Id rather speak with someone who knows more about this spesific vehicle than I do. A few questions to trow out there.
Do these specific vehicles that year and model come with a knock sensor?
How reliable are those oil pumps?
The water pump he replaced just about 4 years ago, so I am not exactly sure it would be that. He thinks its a rod or a vavle. I told him It might be an oil pump, since he always checks his oil, always adds if needed. I told him about my crown vic that I had also had a faulty oil pump that eventually caused the rod bearing to fail due to lack of lubercation, well that happend becuase I kept driving despite all the warnings. What are your thoughts on this, I know its not much information, I will be going out to his car with a flashlight and see how his oil pressure gauge reacts. If its low I would guess it means the pump is not working properly. Thanks guys

forgot to ask, do these cars have a distributor?

[SCT]

Yea, 'these' cars have distributors. And there's no knock sensor as far as I know. For oil pumps, I don't know how long they would last, my car is sitting on 241000 miles with its original oil pump.

Of course, lack of info... I bet it's the valve, carbon build-up is not good. If it's misfiring with super loud clackity-clacks, rods gone.

[nizzehult]

It's unlikely the oil pump. Never heard of any japaneese car - ever - having problems with any part in the lubrication system. These engines just keeps going... How would you describe the sound? Could it be the alternator? Or is the timing belt about to give up? These cars are too old for having knock sensors.

[canadianae92]

90 and 91 gts' have knock sensors but their function is to pick up predetonation not a rod knock! 4afe motors didn't get knock sensors in 90/91 I don't think.

If its an actual knock coming from the bottom end it could likely be a rod or bearing. Check for loose accessories first.

[REN69]

If it's a GTS there would be no dashboard light that I have seen... however there is an oil pressure gauge, if that goes lower than half I start to get worried, usually if it goes lower than half to quarter it's time to put more oil in.

Has anyone looked at the car? maybe it's not rod knock but something else.