99 b20, MSD cap, external coil, 1 degree colder plugs, timing retarded 4 degrees
New distributor rotor, p75 ecu

All motor its fine but backfires & misfires once I start spraying Any help/suggestions on this??

 

Make sure your plugs are gaped right. Could also be a weak coil.

 

Does it just pop upon activation or does it just pop and fart as long as the system is activated?

Dry systems are usually pretty slow to react on the fuel side which can cause a lean surge upon activation. If its crapping out for more than half a second you have bigger problems. What is your fuel pressure before and after activation? What bottle pressure are you running? How do the plugs look after you try to use the bottle?

 

Factory gap on plugs, Ive been spraying for over a year now and have had no problems until today when I installed a Zex bottle heater and retarded the timing. Pressure on the bottle is 910-930 consistent, fuel pressure b4 spray is 38psi, dont know during spraying though. It basically misfires all the way up to about 6-7k. Ive also got RC 310s and an afc. The plugs are all consistent--grayish/light white. I checked the plug wires, the MSD coil itself is about 6 months old maybe my fuel pumps bad?? Ive noticed with the car idling I'll pull on the throttle pulley to accelerate and the fuel pressure goes down. B&M fpr. Thanks for the suggestions/input so far guys cuz Im stumped keep em coming please!!

 

Ya, sounds like you may have a fuel pressure problem to me. Try to make a quick burp on the bottle and keep an eye on your fuel pressure and see what its doing.

 

Thanks bro Ima check on that, any other suggestions go right on ahead

 

I believe the zex kits regulate fuel based on bottle pressure.....the more pressure they have the more fuel they will add...the bottle heater will casue more pressure

deff get a wideband on that thing