Couple of questions for a '91 Nissan 240SX

[Daryl]

I just recently got a '91 Nissan 240SX & I'm learning how to work on the car myself. I just bought a guide from Chilton from Amazon but I have a few questions that some of you might be able to help me with.

1) When I'm driving the car, if I roll the window down I can smell a strong gas/exhaust type smell. I just had my muffler, cat, and some piping replaced so I'm doubtful it's that. I was reading about how the fuel injectors go out are 120k and my car is at 180k so I figured that could be it but I'm not sure where my fuel injectors are located at (thus why I ordered the book). I'm just wondering if that's possibly where the smell could be coming from.

2) My wiper motor seems to only work half way. My wipers work fine but the actual part that squirts out the water doesn't. I've checked the tubes and they all seem to be connected and there is water in the reserve bucket. When you hit the water button it doesn't even sound like it tries to shoot which leads me to one of two possible answers. 1) if it has a fuse then it's blown or 2) the wiper motor (located at the top near the passenger side) is dead. Any other ideas or know if a fuse exists ?

My last and final question for now...

3) When you open the hood there is this semi-big plastic tube that's on the driver side near the radiator / headlight area that's going down but on my car is not on (like it's came off) but I can't seem to get it back on either. Any idea what this is for or if it hurts my car in anyway ?

Thanks in advance.Daryl