SOLVED: '73 2.0 w/ FI started burping/backfiring, (sounds like popcorn in the microwave) Options

[DC_neun_vierzehn]

My '73 2.0 w/ fuel injection started backfiring a couple of days ago and seems to have gotten progressively worse in the last couple of days. It's not constant. Seems to worsen as engine warms up. I've owned the car since April and it ran fine when I purchased it.

Where should I start with trouble shooting?

Disclaimer - my mechanic/engine skills are very limited.

Thanks in advance.

[BeatNavy]

My '73 2.0 w/ fuel injection started backfiring a couple of days ago and seems to have gotten progressively worse in the last couple of days. It's not constant. Seems to worsen as engine warms up. I've owned the car since April and it ran fine when I purchased it.

Where should I start with trouble shooting?

Disclaimer - my mechanic/engine skills are very limited.

Thanks in advance.

Could be a number of causes that are fuel or ignition-related. Is it a popping that sounds like it's coming from the exhaust, particularly on deceleration? If so, my first bet would be that you're running too lean. Running lean can be caused by fuel obstruction somewhere (filter, lines, clogged injectors) or low fuel pressure or several other things. But it could be ignition / timing related, too.

One test you could try would be to temporarily disconnect the ambient temp (T1) sensor. It's a two wire connection on top of the manifold near the TPS. That will artificially enrichen the mixture a bit and may give you a clue if it's running lean.

I'd also just start looking around the engine bay for loose or disconnected wires / hoses, such as injector plugs, trigger points, spark plug wires, etc.

More info would be helpful, too. Does it run fine when you're NOT hearing the issue? Good power, etc.?

EDIT: Another possibility could be an exhaust leak somewhere. You can get popping, especially on decel, if you have a poor connection from HE's to muffler, for example.