backfiring after o/r x install

[1994Vib.RedGT]

I just recently installed my bassani o/r x and ever since I have, when I downshift, or rev in neutral up past about 2500~3000 RPM I get backfiring. Especially if I downshift and the revs go up to about 3000 it sounds like a gun going off, why is this??? Does it have something to do with the lack of cats?

 

[marine_2003]

After installing you need to change the timing.

 

[1994Vib.RedGT]

I just did that 3 days ago when I installed new plugs and rotor/cap. timing is at 10 degrees, timing chain is one month old, timing is a non-issue, other opinions?

 

[90bronconate]

After installing you need to change the timing.

???

 

[JJPA]

Im not 100 percent positive but it could be because of the lack of cats. How about disconnecting the negative battery cable to reset the computer. I dont think timing should be an issue.

 

[90_Red_LX]

Hmm, mine doesn't really backfire unless I run 2nd gear up hard and let out real quick, so I don't know. You may be runnin a little bit rich. Does it do it at WOT? I usually just get these little "pop" sounds.

 

[ALMOSTFINISHED]

Is it backfiring on acceleration or deceleration? If its on deceleration its probly just from lack of backpressure and more frreeflowing exhaust. What mufflers are you using?...scratch the muffler question, just read the sig. What size piping tailpipes do you have? possible popping from a 2 1/2 inch to 2 1/4 inch tails??

Nick

 

[RYC CUKR]

On the first O/R H I put in I had a few exhaust leaks and it would pop and backfire pretty bad on deceleration. Went through and tightened everything down really good and it took care of most of it. Still had a little popping on deceleration but not nearly as bad.

That said the 93 I have now pops on decel pretty good. I know that it is running rich and that is part of the problem but even when the mixture was good it would pop some. Kinda part of havin an O/R pipe.

 

[1994Vib.RedGT]

the popping is not bad, it is the gunshot sounding backfires during downshifts that bother me.