had same prob before and it turned out to be bad igniter.... distributor was working perfectly fine around 350 hp but started misfiring around 600+whp.. changed the igniter and problem solved!!! good luck....

 

Well I gapped the plugs down to .23 tonight and took a spin. Power was smooth and felt a lot stronger... same psi and all. So far I am very pleased with the outcome. Im going to take it to work tomorrow and see how it does then.

 

leaving the gaps at 15 i made 401whp at 18 or 19 psi on a ls non vtec

 

I love bumping old threads, curious tho did u ever resolve this issue? Im having similar problem and doin research.
thanks in advance!

 

sorry for the 3 month bump...

I am having the same issues. 2nd gear @ 20psi = smooth pull. when i shift to 3rd gear @ 25psi it breaks up.

What ive done so far.
-my tachometer used to bounce around. i suspected the ignitor and changed it with a used one that my tuner had lying around. It fixed the tach problem but could that mean there may be something else wrong with it? being they are 100$ from advanced, id rather not guess.
-changed plugs from ngk5671a-8 to bkr7e gapped to .022
-msd cap, wires, rotor and external coil is less than a year old. I understand it could be the coil, but i was steered away from that because of its age.

plug gap? coil? ignitor?


thoughts?

Thanks!

 

Check electrical system. Have battery load tested. Monitor voltage at the battery when testing. Ensure alternator belt isn't slippng.

 

telling us what plugs your using doesnt mean anything unless you tell us what power your making

i jumped from a bkr7e to a platinum version, upgraded mygrounds and plug wires and my similar problem went away

 

sorry. i am making 450hp.

recently i have been having some weird issues. one of the issues is it will randomly start bogging when i come to a stop. the rpms will go from 1k to 500rpms and back. ]

other problem is, the car will start smoking quite a bit. but these issues are not consistent.









Re: Ignition breaking up under higher boost
telling us what plugs your using doesnt mean anything unless you tell us what power your making

i jumped from a bkr7e to a platinum version, upgraded mygrounds and plug wires and my similar problem went away

 

Ok Im having problems with my ignition now ugh. Everything worked great in my other car. Just rebuilt the motor.

Will run fine to about 20 psi then anything more then that will see breakup at 7000 rpm.

Wires are only about 4 years old, NGK blues in good shape. Brand new NGK 9 heat range plugs gapped to .022. Distributor condition is unknown but I ran it to 30psi before the rebuild with no issues. AFR's good, voltage solid 14-14.2. Grounds are brand new around motor

 

4 year old plug wires on that kind of setup - I'd change them on my NA 10:1 CR ZC if having a similar problem.

Process of elimination. Voltage is good under load. Plug wires, cap, rotor - change the plugs too. Anything you change, that in the end is good is a piece that has lifespan limits anyway. Spark Plugs, cap, rotor, wires all get changed. So, you may have a couple of fairly inexpensive spare parts. I have a spare new dizzy for my ZC from troubleshooting.

The plugs or wires, cap, rotor may look ok to the naked eye, but at high RPM and high voltages electricity does some real strange things.

That's how I do it.

 

check your battery and alternator

 

Is that not a good voltage?

 

~14v is good as long as it's holding stable when under maximum load. His suggestion is good, that's an ofter overlooked thing and it absolutely critical with a setup like your's - everything is electric. Fuel delivery and ignition need max power for max performance so battery and alternator need to be solid.

 

Yeah it's stable. I think Im goin to step down in the heat range of plugs since 9s are a little cold in this weather.

 

Have you pulled the distributor cap off to make sure it's clean and dry? Rotor in good shape. Could be arcing inside or some other high voltage breakdown. Even the plug wires could be causing it or a bad spark plug.

How about fuel pressure? Can you monitor it under load?

When you find it be sure and post the results.