Hot Rod Forum banner

1 - 6 of 6 Posts

·
Registered
Joined
·
61 Posts
Discussion Starter #1
I just got my exhaust done on my '83 mazda B2000 (not a ho rod, but this seem to be a good place for an engine help). It has a short exhaust, muffler right at the collecter, and a short tial pipe after that. The entire exhaust ends 2 feet after the cab.

I was driving it around for a bit tonight and every time I downshift, it pops like mad.

I'm thinking I have a lean mix maybe? What else could cause this.

If I do have a lean mix, how would I correct it.
 

·
Registered
Joined
·
83 Posts
What kind of muffler ????
Also, the 2 foot tailpipe might add to the problem...
 

·
Licenced Automotive Technician
Joined
·
1,625 Posts
With this info, it sounds like not enough backpressure. What kind of muffler is it? Is it straight through? I would hazard a guess that you may need to lean the carb out a bit to compensate for the reduced backpressure, but I'm not sure....... it's been a long day.....can't think anymore......:drunk:
 

·
Premium Member
Joined
·
2,370 Posts
Short exhaust, and a leak down near the collector or donut gasket will cause this. Check for leaks and/or try extending the exhaust a bit.

Does it do it only when you down shift? Try giving it a lot of gas and then taking your foot off the gas totally when your goin down the highway. It will probably do the same.
 

·
Registered
Joined
·
88 Posts
There is a difference between a lean pop and a backfire...
To me it would make sense that it is a lean pop because of your exhaust mods. The way to fix that is to get a performance chip which will among other things richen the mixture, or get injectors that have a higher flow rate. If it is carbed richen up the secondaries and play with the timing if needed. Is there an 02 sensor light? If it is not equipped an o2 sensor and gauge will tell you your mixture.
 

·
Come Home Safe Soldier
Joined
·
846 Posts
It is more than likely the exhaust.Take a V8 car for example,run headers on it with a short section of pipe and a muffler.Same effect.With the same engine as on a race only car,where headers are your only exhaust you will hear that same sound.Did you request that setup?
 
1 - 6 of 6 Posts
Top