Smelly diapers

[npl]

My diapers smell clean when they come out of the washing machine and when they are dry. We use fragrance-free detergent, and the diapers smell of nothing at all.
But, as soon as dd pees in them, we know it, because they smell bad. Almost like they smell burnt.
What do you think is causing this and how do I remedy it?

[junipervt]

could be bacteria that is growing b/c you are not getting your diapers clean enough. 1st you'll need to kill the bacteria. You can use a little bleach or GSE to kill the bacteria. But you'll still need to work on your wash routine to make sure it does not come back.

A few questions to ask are...
-are you using enough water? Do diapers have room to move around in washer?
-is your water hot enough?
-is your detergent leaving behind buildup?
-are you're diapers not rinsing clean?

[npl]

I'm not sure if I'm using enough water. I have a FL HE machine, with no option to adjust the water level. So, I run either a soak or short wash cycle with no spin, so the load is heavier for the main cycle, to try to trick the machine into using more water.
The water temperature is definitely high enough.
Not sure how to tell if the detergent is leaving residue or the diapers are rinsing clean. They definitely smell and feel clean, though dd's poop stains like turmeric (clothing, too - not a diaper-washing issue).

Here's my current wash routine:
Cold water soak or quick wash with detergent and no spin
Hot water was, heavy cycle, with extra cold rinse, with detergent
Rinse-spin cycle with warm water.

The diapers have smelled since she started using them, but when she's in disposables she doesn't smell.
I tried adding baking soda to the wash and vinegar to the rinse (together and separately) and didn't see a difference.
I haven't seen detergent bubbles when I've looked at the washing machine during the final rinse cycle.