bike fire when kicking in nos

[chefster]

For some reason I had a back fire and hesitation with my zex kicking in....I did back off my timing a week ago to play around with spark knock..could that have caused it?

 

[The Green GT]

Did you change the plugs for the ZEX? I think you have to go with cooler plugs.

 

[chefster]

like what?

 

[zZsKyZz]

autolite 24's that's what i usta use with my NOS 5115 kit.

 

[94gts]

a nitrous backfire is when there is too much fuel in the intake. but if its a dry kit then this wouldnt be what happened.

 

[chefster]

ya it is a wet kit,i put my timing back up a bit ,I'll see what that ll do...and I think I'll clean my air filter.....cause it worked perfect last summer with this same set up.

 

[94gts]

since its a wet kit you may have sprayed too low in the rpm range

 

[SWYZ721]

I agree, it might be two low of an RPM that you spray at.

You might also want to check the fuel pressure when spraying, if the pressure is too low you might be getting a good mist.

 

[chefster]

ok , the zex kicks in at full throttle,thats the set up. It worked great last summer. Now I get this powerful "BAM"with a hesitation. Other than that the car runs fantastic.

 

[gcomfx.com]

Double check your jets are correct. Also the reason to check fuel pressure, isn't always because of low rpms. Most people take the easy route and pull the fuel from the schrader valve, which is basically taking fuel from one bank of injectors. Seems to be be fine when you have plenty of fuel, but can be a bad thing when you don't have enough.

Pull you codes and see if one bank is running lean.

And I also agree about the plugs. They cost a buck a piece. You did say you were messing with your timing. I had NEVER melted a plug until a couple w/e's ago and I used to spray at the track every other w/e for 4 years. Took a year off and bam first bump of the timing, toasted a plug.

Also, don't forget - gap them at .035

 

[chefster]

gettin new plugs now ,gapin at 35,thanks.