Hi Everybody and happy new year

I have a misfiring problem, the cylinders number 1,4,6,7 are misfiring. My car was running perfect but the misfiring problem started today after to washed it. What can be the problem? Maybe some water come into the distributor?

PD: I'm sure that I have misfiring problem because I unplugged each spark plug wire and when I unplugged the wires from 4,8,1,5 cylinders nothing happened, the engine sound doesn't change

 

Gotta be the carb or water in it. Affecting one side easily.

 

Why could be the carb if the affected cylinders are from both engine sides? What can I check on the carb?

EDIT: sorry the misfiring cylinders are 1,4,6,7

 

Advice is based on a dual plane manifold. If you follow the individual intake runners you'll see that one side of the carb supplies the ones you listed, the other side of the carb will supply the other 4. (2,3,5,8) They do crossover.

 

some of the dist caps have a air vent. DO plug it with JB-weld. took me 5 years to figure that out. trust me.

 

May be will be dried up tomorrow. and will not missfire any more.

 

pop the cap off and spray with WD-40. then dry with starting fluid.

 

Also double check the firing order

 

Hi!

Now the car is running well, I cleaned all the spark plug wires, distributor cap and checked the firing order but I'm not 100% sure that all the cylinders are working because if I unplugg the wires number 1,4,6,7 I don't notice a big difference like if I unplug the other cylinder wires. How can I be 100% sure that I don't have misfiring cylinders?

 

check the plugs. the spark plug is the window into the chamber.

 

I already did this, all the spark plugs seems to be working and doesn't seems to have a lean condition

 

An easy way to check which cylinders are firing is to use an IR temp gun. You can pick one up cheap at home centers. Shoot the exhaust manifolds an inch or two from the head at each cylinder, the significantly colder readings are your misfiring cylinders.

 

a moment ago I picked up the car from the mechanic (he was doing a electric repair) and in the road the car started to misfire again, I checked again and the misfire cylinders are the same 1,4,6,7 but If I engage the choke or accelerate the misfire disappear so the misfire is only during idle or smooth acceleration.

What can be wrong?

I don't know if the follow information can help to have a diagnostic but the carburetor has a spring base needle and the other needle isn't spring based, when I bought the carb it already has the non spring based needle. Can this produce the misfire?

 

Sounds to me like you are fighting a lean missfire... (Not Getting enough Fuel)

 

How can I try to fix it? Maybe raising up a bit the idle speed? or movin the idle mixture screws anti clockwise?

When the engine is misfiring If I cover the carburetor horn air with my hand, the idling speed increases and misfire disappears

 

First make sure you do not have any vacuum leaks....
Second Make sure you have good fuel pressure and the fuel filter is not plugged.....

 

Sounds like carb problems huh?

 

The problem was a vacuum leak near the PCV hose, I fix it on the road trying to start the car because it went broken just a few moments ago and now the misfiring is gone, I hope this is the ultimate solution.

I'm going to open a new thread to look for help with my new problem.

Oh god, I'm the guy of problems in this forum