Sounds like a hose or plasticky part has come loose or somehow shifted, or a heat shield isn't doing its job, and now you're plagued with a stinky ride.

Idling higher than usual suggests that the throttle cable is out of place and/or bound up, possibly being the source of the burnt rubber smell or its movement is being affected by it.

The cruise control cable could also be an issue here, as well as the CC canister and rubber hoses.

Being "new to fixing cars", you might wanna find a YT video of a Gen1 SC Xterra to see what things should look like under the hood and then compare it with yours. If you see something different or out of place, it could be helpful to inspect that more thoroughly, or it could just be something the other owner did but has no bearing on your issue.

Probably the biggest thing to keep in mind is that you're looking for stuff that gets hot, so look more closely at those items: heat shield, exhaust manifold, cats, etc. Also, look for parts that are rotating (belts, pulleys, etc.) to see if anything is touching them that shouldn't be.

If you're not sure what you're looking at, take pics, share 'em here, and there will be plenty of members who'll know what it is and give you a nudge in the right direction.

Someone may also have already dealt with this and knows just where to go, saving you some time and effort.

 

Thank you! My dad is the 2nd owner. My uncle paid cash for it when they rolled these out. YouTube is so helpful. First car I fixed myself was easy wiring harness on a jeep.
The belt didn't appear obstructed in any way. I did check hoses but that's not to say I didn't miss something.
My speedometer is also jumpy at times, works fine sometimes, or just not at all. Does that play into anything? Now when I crawled under to retrieve my dropped radiator cap, I noticed a small amount of fluid that to me seemed to be water. Fitting since when I removed the cap water or antifreeze came out too. But it did not smell like water, wasn't greenish tinted like coolant, and def was not oil. What could that be?

 

Back on topic (we can get to those other things later on...), were you able to find anything that appeared to have been damaged from heat?

I'd say, find the smell and you may find answers to some of those other issues as well. Something isn't right and your olfactory is tellin' you so.

 

I don't have a Gen 1 so can someone tell me if they sense intake manifold vacuum to control ignition and fuel functions? If so, I would be looking for a displaced or broken rubber vacuum hose that has dropped on to a hot exhaust manifold. Old school distributor engines with vacuum controls that I used to have would certainly mess with your idle if you had a vacuum hose off.

 

I don't have a Gen 1 so can someone tell me if they sense intake manifold vacuum to control ignition and fuel functions?

vacuum on this engine only goes to EVAP purge, fuel pressure and boost control. Some of the NA trucks had EGR. MAF is used for fuel mixture control and distributor timing is controlled by ECM based on engine speed/load/temperature etc

 

No. I did not see anything that seemed charred or melted or out of place. Im about to look at a video like you suggested and double check. And recheck my oil and such too 🤷‍♀️ the other questions I ask wondering are they all tied together? They started prior to the smell. If I locate the smell ill def tell you. Thank you again!

 

Burned rubber smell or could it be a burned oil smell?

I have that same Xterra. A couple of years ago, the valve cover started leaking a tiny bit of oil onto the hot exhaust manifold. It wasn't enough to notice a big difference in oil level but it smelled really bad. When I pulled the Xterra into the garage, it stunk up the entire house. Only smelled it when X was fully warmed up.

 

No. Not burned oil i don't think. I actually spilled some when topping off my oil and I didn't get it cleaned good enough and after idling a bit I could smell the burned rubber and then the residual oil too.

Going with the exhaust though... So I am pretty sure I've got an exhaust leak (idk if that's even something that can happen because isn't that exactly what it is fumes escaping?) Would that create or cause the rubber im smelling?

I only know about under the hood SOME. Deff nothing as far as exhaust or transmission.

Also mentioned was cc wire.. As far as I know its fine. It hadn't worked but I stumbled upon why it wasn't when adhering a penny to my brake pedal a few month back. Its been working ever since.

 

Now could the clutch smell like burned rubber? I haven't noticed the smell as strongly and it was upon getting warm until parked. Not anymore. Im asking clutch because I have noticed more freedom in the pedal before "catching". I had it throw out baring, master cylinder and slave cylinder replaced in the spring. It had been really tight so do they just loosen over time?

Honestly I do have a lot of questions🤣 sorry! Do I make new threads per each question/issue/query or all here?

 

Now could the clutch smell like burned rubber? I haven't noticed the smell as strongly and it was upon getting warm until parked. Not anymore. Im asking clutch because I have noticed more freedom in the pedal before "catching". I had it throw out baring, master cylinder and slave cylinder replaced in the spring. It had been really tight so do they just loosen over time?

Honestly I do have a lot of questions🤣 sorry! Do I make new threads per each question/issue/query or all here?

A burning clutch has its own different smell.
Could it be the fan clutch making the smell?

 

Did you use the spare tire? Does the exhaust system have any broken hangers? Exhaust might be touching the spare tire.

 

I haven't used it but its ok. When looking for condensation though so i may double check. Its intermittent also.

 

Not the best pic.

 

Would this do it? But I swear it under the hood

 

You may have a separate odor issue going on under the hood but this looks like a fairly active leak here in this picture. In the lower left of the picture it appears the frame is wet and the exhaust heat shield looks like the migrating leak fluid has dropped on to that shield and it is dark brown from burnt fluid. Is that what you were seeing under there?

 

Yes. So much grime. My dad never did any maintenance on this. For 4 years. So I'm not sure whats new or old. Its a mess I do know that. The wetness on the frame is the same fluid in my reservoir for radiator. Or they smell the same with same consistency also

 

Well it certainly doesn't seem likely your clutch would be worn out in a year. The bottom of your transmission looks pretty wet with some kind of leak there and your exhaust pipe tip is pretty black inside and that would be a sign of the engine running rich[too much fuel in the mix]. The fluid leak looks like it's dripping down on to the exhaust heat shield there in the picture.

 

So all that dirt is from a leak? I have a small oil leak I was told anyways. But when I started it today a belt squeeled so loudly and now my check engine light is on

 

Well, sounds like your burning rubber smell under the hood was something that the drive belt was trying to turn and it was resisting enough to originally cause a burn smell but now it has progressed to the point that it has created a startup squeal and a system engine code to go with it. Are you able to give us the code and check for a seized up pulley or idler that belt is attempting to drive?

 

A tailpipe that's black is normal if the car is ever driven. No engine burns fuel perfectly completely, so some soot is bound to happen.

You may have multiple leaks.

If it smells like coolant (radiator fluid), and you touch it and it's not oily, then it's most likely coolant. If it's slippery, that's just the chemicals they use, but if it's slippery and oily (kinda sticks to your fingers), then it's more likely motor oil, tranny fluid, or PS fluid. And I'm sure we all hope it's not brake fluid!

 

Ok ya'll sorry I just now getting back.

The squealing upon starting happened twice and hasn't again. The check engine light has gone off too.

 

Welcome back. I guess you probably have been too busy to check for rough turning pulleys or idler wheels in the belt path to see if you can narrow it down? One of the best ways to do that if you don't already know is to remove the drive belt and proceed to spin each of the pulleys to see if you find one that is not spinning relatively freely.