Intermittent Burning Odor In Engine Bay

[petethepug]

Yes, it’s possible. A good indicator for overcharging and bad grounds is heat. Start by feeling for hot wires in the harness around the suspected areas. Battery posts or it’s wires should not be hot.

 

[Big Mama]

It could but it sounds more like a frayed wire or something touching the exhaust manifold on that side or possibly coolant leaking from the overflow. Check those hoses and clamps. You can get an inspection mirror or a fluoroscope from HB cheap.

 

[LegalBrief]

Totally different direction here.. have you looked for critter damage or droppings? My old truck had spot the critters loved, when it got hot the droppings would “roast” for lack of a better word. Pressure wash and sone steel wool was all it took for them to move out.

 

[EddieC]

Totally different direction here.. have you looked for critter damage or droppings? My old truck had spot the critters loved, when it got hot the droppings would “roast” for lack of a better word. Pressure wash and sone steel wool was all it took for them to move out.

No critters.

 

[EddieC]

Maybe I can refine to current observations.
Odor is most prominent under harder working situations like pushing or going up a hill.
Casual unstressful driving or idling in the driveway it's barely noticeable.
It is intermittent, varies with driving conditions. It is not constant like a leak would seem to produce.
It still seems near the battery/coolant bottle.
Coolant looks and smells ok.

 

[Big Mama]

Unless it’s a fluid landing on your manifold or exhaust somewhere and burring up completely there should be some kind of evidence left behind. An inspection mirror or fluoroscope might help you find it. Harder acceleration means the exhaust is hotter so more smell. I wonder if your O2 sensor wires could be the culprit. Their’s one right where you’re noticing the smell.

 

[EddieC]

Unless it’s a fluid landing on your manifold or exhaust somewhere and burring up completely there should be some kind of evidence left behind. An inspection mirror or fluoroscope might help you find it. Harder acceleration means the exhaust is hotter so more smell. I wonder if your O2 sensor wires could be the culprit. Their’s one right where you’re noticing the smell.

Worth a look. I would assume that a burned sensor wire would throw a code though. Tomorrow is another day to get back at it.

It seems so focused near the battery I wonder if something in there failed or got damaged by the alternator.

 

[Big Mama]

It could have but, like the O2 wires you’d probably know. It’ll be interesting what you see bc usually you can see stuff pretty well from the bottom side.

 

[petethepug]

I usually discovered stuff like this was electrical.

* A heated / cooled seat harness baking.
* hvac fan resistor overheating
* hvac duct modulation servo going.
* battery or super fuse poor connections.