backdraft408

long story short i have a 408 in my 2000 ss that has backfired a total of three time in the past month. all three times car was being driven in town, and has happened when after i stopped at a stop sign and then kind of got on it. my tuner says its not a tuning issue and has to be machenical problem. wondering if anyone has had this problem? whether its a spark plug, timing, fuel, tuning or injector problem i just want it fixed and hoping someone else has been in my shoes.

96capricemgr

iTrader: (1)

Last time I had an engine backfire on me it was because I had used the wrong intake manifold gaskets and it had a vacuum leak at the port between the head and intake. This was a gen 1 engine not a Gen 3+ but I would expect a similar result if a port seal got rolled out of it's groove or something during install.

backdraft408

it also seems to run a little on the rick side at idle

96capricemgr

iTrader: (1)

If one cylinder is sucking air at the port the O2s will "see" that lean lean condition once it is mixed with the other 3 cylinders on that bank and dump fuel to compensate making the other 3 rich.

Have to remember fueling correction is done bank to bank.

I thought of another case where I had some backfiring, it was a single dead injector on an LT1. One injector was just dripping.

backdraft408

the more i get into it the more its looking like a fuel problem

backdraft408

i know something is wrong when it backfires and blows an muffler off

tjb406

iTrader: (4)

i blew 2 off one night but that was a wide plug gap and a lil too much n2o.

Blackpanther99

iTrader: (8)

If the fuel mixture is too lean (not enough fuel) you may have a backfire in the intake, have you checked you air to fuel ratio?

Old Geezer

iTrader: (3)

Some data logging may do wonders for determining wtf is going on..............