Question about past perfect

I'm trying to figure out proper way to use past perfect tense. I came out with a few phrases but I'm still confused with the differences. Can someone explain to me the difference between each phrase?

1. The police had stopped him because he drove too fast.

2. The police stopped him because he had driven too fast.

3. He drove too fast so the police had stopped him.

Thanks guys! If I made any other mistakes, please point it out kindly.

Solution 1:

According to Grammarly,

The past perfect tense is for talking about something that happened before something else.

So of your three examples, (2) is the best example of proper usage for past perfect. The fast driving came before the police stopping him, so "drive" takes the past perfect tense.

For (1), this is technically grammatical but it conveys a different idea than (I think) you're trying to express. To be a good use of past perfect, there would need to be some other event in the picture which took place after the police stopped him. For example:

1a. He came to the party late. The police had stopped him because he drove too fast.

Another way to improve (1) and make it express the idea (I believe) you're getting at, would be to apply Past Continuous tense to "drive":

1b. The police had stopped him because he was driving too fast.

The same kind of issues apply to (3) -- confusion results from reversing the normal use of past perfect. And like (1), these problems could be corrected by relating the police stop to some other, later event -- and also by applying Past Continuous:

3a. He came to the party late. He was driving too fast, so the police had stopped him.