Throwing small flames from 3&4 exhaust now and again and seems as if not firing properly on 3 & 4 cylinders.Checked compressions,spark,reset tappets,replaced inlet gasket.Twin carbs set up of weber 34icts.
Can u help????
The vehicle is a 1974 model.
I have a 1600 sp with a solex h30 pict3 and i set the volume screw 3 turns out and idle crew quater turn into choke cam i checked # 1 piston to top dead center and set the distributor to line up with the rotor head on the mark indicated on the distributer. turned engine on and put the timing light on it and it`s reading 30 degrees when i turn the distributor to get tdc it runs like **** and stalls. what am i doing wrong it failed emissions due to high hydrocarbons. got a reading of 674, carbon monoxide was good @ .12 spark plugs are clean . i`m baffled.? plse help thx . ken
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back firing is from partially open inlet valves , incorrect firing order , shorting across the points , faulty condenser , loose coil wires or faulty pigtail wire from the points plate to the ground ( distributor body)
seeing as to you have put in new points , I suspect that the condenser lead is shorting across to the points plate where it attaches to the moving point spring
also if the firing order is wrong after replacing the distributor cap that will also cause the problem
Pull all the spark plugs and crank the engine over equal times for each cylinder, 3 or 4 complete revolutions will do. All the readings need to be no more than 5% different from the cylinder with the highest pressure.
Intake manifold gasket ,try torqueing intake bolts,or spray carb cleaner around bolts and seem while running see if it rums smoothly while spraying if so new intake manifold gaskets needed. YouTube video check to see.
The Specific code "P0303" is stating that the Third Cylinder or Cylinder number 3 Is mis-firing, thanks to all that you have done this has narrowed it down to two "confirmed" possible problems;
The first is that the Exhaust VALVE itself may be "Burned" and the Second may be a Poor condition or "Faulty" Catalytic converter(s).
This is only a possible cause but please keep in mind that on some certain models (not too sure about this specific model) there are multiple O2 Sensors located in different spots. (usually in or next to the preliminary and primary catalytic converts)
Also one of my experiences lead me to beleive that the Ignition Control Module (ICM) may be faulty causing the injector to not provide proper Fuel to the Cylinder.which will more often than not cause the computer chip to sense the misfiring as opposed to the bad signal from the ICM.