Misfire under load...

[Jasonf860]

Well, like the title says, That's what I've got. I'm going to check out the usual, plugs, rotor, cap, wires... I replaced all but the plugs in october of last year along with that, the coil was replaced with an accel super stock one. Car idles fine, if I rev it in neutral, no stumble, hesitation, or misfire. The idle is a little lopey due to the cam but otherwise it's perfect. Oh, I should add that it doesn't misfire when it's cold, but only once the engine has reached normal op temp. This leads me to think fuel issue... maybe my primary jets are plugged up and when it's cold and richened it runs fine?

If anyone has any thoughts on the subject, I'd be happy to hear them!

P.S. I'm looking for an LXI front brake swap too so if ya got the whole deal, let me know!

[Vanilla Sky]

Sounds like you are running with too much timing. Do you have a timing light? Warm and under load is when you're most apt to ping. Do you maybe have an audio recording of the engine misfiring?

[Jasonf860]

Sounds like you are running with too much timing. Do you have a timing light? Warm and under load is when you're most apt to ping. Do you maybe have an audio recording of the engine misfiring?
See, that's why I posted... For responses like this! I forgot all about timing! Damn it! I am running WAY advanced, beyond the normal advance for the dizzy because I "was" running 93 in it at all times. I let the older brother take it last week and he filled it up! Must have used 89 or something! I'm gonna back it off and see if it helps! Thanks!

[MessyHonda]

sweet...hope you get it fixed soon jason

[A20A1]

Oh, I should add that it doesn't misfire when it's cold, but only once the engine has reached normal op temp. This leads me to think fuel issue... maybe my primary jets are plugged up and when it's cold and richened it runs fine?


When cold, timing is changed as well as fuel.

[Jasonf860]

Well, we can rule out timing, as well as cap and rotor. Backed off my timing, even set it with the light... very slight change..... Pulled the cap, looks like brand new. Same for the rotor. I'll be looking into plugs next, then wires. If that doesn't solve it, Fuel filter (again). If that doesn't solve it, Then i don't know what will. I will of course adjust the valves again before I go nuts replacing stuff....

[A20A1]

Check for Vacuum leak also since vacuum will effect fuel mostly... and timing as well.

[Jasonf860]

Check for Vacuum leak also since vacuum will effect fuel mostly... and timing as well.
Ah, the dreaded vacuum issues! maybe it's time for a vacuum removal!!!!!!!!

[Jasonf860]

Update: Searched for vacuum leaks, found none. Pulled my plugs, Guess what?!?!? 2 of the 4 were worn so bad the center electrode was gone! WTF? Only 15k on those plugs! Replaced them with new NGK plugs and she's running smoother than ever! Now if I can just find the time to do my UCA's and brakes...

[skycam_313]

could that have anything to do with the super stock?

[A20A1]

I thought you said you changed them, guess I read it wrong.

you're running with an air filter right :)

[Jasonf860]

I thought you said you changed them, guess I read it wrong.

you're running with an air filter right :)
Most definitely. The only time I'd ever run without one is if I am doing maintenance like adjusting the carb.

Skycam, I was thinking the same thing! I may swap back to my stock coil and see how it runs.

[2oodoor]

15K miles on a set of plugs actually is not that bad on a carbed, modified motor.

[Jasonf860]

15K miles on a set of plugs actually is not that bad on a carbed, modified motor.
True, and they were normal copper NGK's too.