hesitation and backfire

[erikmendoZa03]

may car has been running fine until 2 days ago, whenever my speed gets over 30mph the engine starts to back fire and hesitates, what could cause that? and how can i fix it? ive changed the spark plugs and wires with NGK. but it didnt solve the problem,

hope someone can give me advice

thanks!

[Braden]

check your points for pitting or misadjustment, also could be fuel dekivery problem, clogged secondariy jets maybe? any other symptoms, just at 30 mph? or also under hard acceleration? best bet is to check points first, i drove my truck around for a long time and didnt even realize how crappy it ran untill i adjusted my points gap

[datto510]

Check the timing? Is there a problem with your carb? NEED MORE INFO ABOUT YOUR CAR!.......pics too. :lol:

[lardlungs]

my first look would be the points ( i bet they are pitted) then the timing

[datzenmike]

may car has been running fine until 2 days ago, whenever my speed gets over 30mph the engine starts to back fire and hesitates, what could cause that? and how can i fix it? ive changed the spark plugs and wires with NGK. but it didnt solve the problem,

hope someone can give me advice

thanks!

 

A sudden change doesn't sound like timing which can change slowly with point wear or not at all with an EI dizzy. Points wear slowly and for the most part just get worse and worse over time.

 

Backfire out the carb or the exhaust?

 

What about the dizzy cap and rotor?

[erikmendoZa03]

thank you for all the replies and advice

about the engine everything is stock original, except for the new sparkplugs and sparkplug wires.ive been running the car without carb filters. (i don know how to tell if my carbs are clogged so im suspecting that could be it) the distributor and the rotor are both original,

the backfiring comes out of the exhaust, it doesnt backfire or hesitates with hard accelerations, it runs fine even i get to 7k rpm, but it starts to backfire when i get to 30mph

 

whats the difference with a backfire that comes from the exhaust and the carburetor?

im not really a mechanic, but how can i tell the difference if the points are pitted with a n non pitted point? if its pitted could i adjust it myself or do i have to change the part?

im thinking of getting a new distributor or a rotor, and replace the old ones.

 

thanks for all the advice

 

p.s

how can i post pictures?

[banzai510(hainz)]

condensor but itf it was bad it would get worse the higher the rpm you go.

ck for side shaft wiggle on the rotor of the distributor.

retime the motor.

 

maybe ck the valave lash but I hightly dought it.

[Braden]

get a matchbox, replace your rotor and cap, set the timing. ka bam!!! 100% perfect ignition system, if problem still persists consult your carbs!

[hogboy52]

Backfiring/hesitation is too lean a fuel mix. 30 mph is the idle transition phase. Accelerating is using the main jets, so no problem there. No carb filter? The idle jet is plugged up. Even with the regular fuel filter, some of the old fuel line material will deteriate from alky fuel mix and shed little black bits that get into the carb.

[hang_510]

when was the last time the fuel filter was replaced?

 

whats the difference with a backfire that comes from the exhaust and the carburetor?

 

im not really a mechanic, but how can i tell the difference if the points are pitted with a n non pitted point? if its pitted could i adjust it myself or do i have to change the part?

 

 

im thinking of getting a new distributor or a rotor, and replace the old ones.

host needed for pix. ;)

 

 

timing is everything!!!

retarded VS advanced timing.

 

 

electronic distributor is a great idea!

 

 

open the points and look between for anything other than smooth, file w/a burnishing tool or replace.

adjustment required for either.

[erikmendoZa03]

my car is really weird, i havent done anything yet but it runs better now, no hesitation so far. i guess with just advices from you all can make a car run better. will do a thorough check this weekend, and change the rotor cap. and get filters for my carbs.