• NAXJA is having its 18th annual March Membership Drive!!!
    Everyone who joins or renews during March will be entered into a drawing!
    More Information - Join/Renew
  • Welcome to the new NAXJA Forum! If your password does not work, please use "Forgot your password?" link on the log-in page. Please feel free to reach out to [email protected] if we can provide any assistance.

still cutting out

91blackbox

NAXJA Forum User
i was piggy backed on another thread but figured i would start another..

issue: ok as i'm driving she will cut in and out.. but only after she warms up....

changed: fuel filter , tps, cps<crank>, cap rotor, plugs, wires, map ...

also the cat was changed a while back so i could pass smog..

any ideas...

i'm not convinced its a fuel issue for the sheer fact that sometimes when she cuts out and kicks back in she backfires....

no problems starting... idles ok.. has alittle shake but nothing extreme...

i did notice some play in the dizzy shaft.. but i have heard play is ok.. its up and down about an 1/8 and side to side about 1/8.....

but again i'm also not convinced its the dizzy cause she runs fine at idle...

I'M BAFFLED!!!!
 
Up down, Ok, that is normal. Side to side is NOT Ok. You have a shaft made to spin on its own center axis and it is able to wobble side to side.

When its doing its HULA DANCE a cylinder doesn't get its injector firing pulse--where does the compressed air (minus the fuel it didn't get) go? It is pumped out of course, into the exhaust manifold, where the oxygen mixes with residual hydrocarbons that exist normally in the exhaust (that nasty HC they measure at the emissions testing stations). So, now you have HC, o2, and heated exhaust--ignition. What is the main cause of backfiring? When o2 is getting into the exhaust and igniting with the unburned hydrocarbons.

Any of that sound vaguely familiar?

Good luck.
 
Up down, Ok, that is normal. Side to side is NOT Ok. You have a shaft made to spin on its own center axis and it is able to wobble side to side.

When its doing its HULA DANCE a cylinder doesn't get its injector firing pulse--where does the compressed air (minus the fuel it didn't get) go? It is pumped out of course, into the exhaust manifold, where the oxygen mixes with residual hydrocarbons that exist normally in the exhaust (that nasty HC they measure at the emissions testing stations). So, now you have HC, o2, and heated exhaust--ignition. What is the main cause of backfiring? When o2 is getting into the exhaust and igniting with the unburned hydrocarbons.

Any of that sound vaguely familiar?

Good luck.


some but not alot.. it makes sense though
 
Have you ever refreshed all your engine bay grounds? Joe probably has a pre-written response on ground refreshing that he could insert into a post. I woulda done it but don't know how. He's more computer savvy than I am, but we both share an emphasis on refreshing grounds as we worked on these things when they were new and the insufficient grounds were a problem back then. I'm sure they haven't improved with age nearly as much as Joe and I have.............
 
Back
Top