Backfiring up and down the streets

[canucke30]

Hey guys,

So last week I replaced the diff on my car. It took a couple of days and the car was jacked up from the back for about a week. Got the new diff on and now the car is backfiring like no ones business... constantly! I am pretty sure it has nothing to do with the diff... there is no way it could, could it? Anyway, i can tell the car is running rich... can smell the gas as soon as I start the car.

How do I adjust the mixture on a fuel injected m10? I am hoping that is all it is. I just replaced all the plugs, wires, distributor, and coil a few months ago.

[Hey_You]

Is your timing still accurate? Fuel pressure correct? Coolant Temperature sensor. There are many things that dictate a rich running condition. Also, with the backfire, any holes/leaks in your exhaust?

[canucke30]

Is your timing still accurate? Fuel pressure correct? Coolant Temperature sensor. There are many things that dictate a rich running condition. Also, with the backfire, any holes/leaks in your exhaust?

There definitely was a hole of some sort in the exhaust as my muffler is now just hanging from the hangers and not attached to the pipe at all...

So, do you think the leak/hole caused the backfiring and it eventually just blew off or did the backfiring cause the hole/leak?

Basically, which came first, the chicken or the egg?? :)

[Hey_You]

The hole caused the backfire. Repair it (new muffler, and piping if needed) and it should go away.

[ieatpeople]

The hole caused the backfire. Repair it (new muffler, and piping if needed) and it should go away.

if the car is running properly, there is no way in hell an exhaust leak would cause a backfire.


for example: i drove my e30 for months with a longtube header and no exhaust, and it never backfired. it was loud as hell, and plenty quick, but no backfire occurred, because the engine was running correctly.

another example: my dd toyota has a blown flexpipe. and while it does sound terrible and has no torque, it does not backfire. because it runs right.

therefore, there must be another problem. check 02, check fpr, check timing.

[devon.818]

i vote o2 sensore combined with shitty exhaust.

[canucke30]

The o2 sensor would explain the car running rich, hey? I've noticed my fuel consumption is WAY out of whack recently as well.

8 gallons in 3 or 4 days driving maybe 20 miles/day? As far as my calculations are telling me, that is about 7.5 mpgs.

I am guessing I should be getting a bit better than that!

[Hey_You]

Change the o2 sensor for maintenance, replace your coolant temperature sensor because well...it's like $30 and can cause a whole lot of issues (running rich being one of them), and replace the hole'd up exhaust because...well, it needs to be fixed.

[jlevie]

The most likely cause would be intake leaks. The "rich smell" is probably unburnt fuel from misfires.

[Hey_You]

Ah yes, forgot that one. The rubber intake elbow is about $30 or so (not sure if that is at cost of list). Fix that too if its torn

[matt0300]

Its an afterfire. Backfire fires through the intake.

[Hey_You]

Sounds like ignition is too far advanced?