Bonneville Backfires!
 

www.fearthepearl.com/vids/rev.avi

Thats the link to it, i did that today AFTER my Cat was installed, but, it has done that since i bought the car back in May 03. Ive replaced, plugs, wires, MAF, O2, PCV, Air filter, Fuel filter,and it has done nothing
I dont know what to check next!
Ive replaced it all! lol
Also here is an other vid,
ok www.fearthepearl.com/vids/freeway.wmv of me on the freeway BEFOR the new High Flow was installed, the last clip u can really hear it missing..
Now she cranks WOT like a dream!

Videos Courtesy of Jason (BonneMe) thanks!

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Ok Matt. Here we go (and keep in mind this isn't gonna be easy, but we'll get it).
Before Fuddy and Andy get in here and start asking all the other questions:

1. Disconnect the battery for 30 minutes, then pull a fresh set of codes.
2. Buy a $10 stethescope and listen to each of your injectors. Do they sound the same?
3. Pull all 6 plugs and inspect them. Do they all look the same, or is one different?

An update on the condition of your fuel system (filters, etc) and ignition components would be a big help.

well, ive tested the coil packs thats about it (ohms) they all were at the minimal OHM reading line.
I will get a Scope tomorrow, and try this.
Also i will reset the pcm and pull the codes with my paperclip!

One more thing......I forgot.....does it do this hot, cold, or any time?

hot

Ok....being temperature sensitve makes me lean towards the electrical/electronic side. This means ignition is alot more likely than fuel (especially in a backfire condition).

I'll wait until all the stuff already mentioned is nailed down (codes, etc), but I have my ideas ;)

Oh i dont doubt you do LOL

backfire
 

Might be an ignition timing problem. Possibly crank angle sensor? That was one of the symptoms of mine going bad.

Maybe the ICM is going.... Matt you never told it me it was only when it was hot! I think it's time for a DIS4 wren? :lol:

well i took the scope to all the injectors, they sound the same, also i un hooked my battery for an hour, and after that no new codes were stored.
So now im outta ideas!

The popping noise in the videos.... is that the backfire?

This maybe a dumb question... but what is... what causes a backfire?
I thought it was normally like an obscene bang coming from the exhaust... like a gunshot.

Does the noise happen at any speed/rpm or only at WOT or when you come down from WOT?

if im not mistaken a backfire is caused when detonation occurs too late. causing part of the explosion to come out the exhaust(or somethin like that) ive seen flames shoot out the exhaust on certain backfire occasions(not on the Bonneville).

Backfiring
 

Actually, backfiring usually occurs when unburned gasoline vapors ignites in the exhaust pipe. This is indicated by a loud bang. Sometimes a flame will come out the tail pipe.

Re: Backfiring
 

If a car is backfiring.... does it happen at random (at any rpm).... or only at (or after) WOT?

Depends on what's broken. A bad spring could make it occur more under load.