MISSFIRE ON ONE CYLINDER ?

[cudaneil]

    Hi guys,  I lifted the hood and had a quick look between snow showers !     And i dont have a power booster,so no power brakes on mine Chryco.

        Also Mark,  my plug wires are quite new and i have switched them around,still misfires on the same cylinder,with a new spark plug   

     Have bought a new distributor cap and rotor (a nos one with the brass contact terminals) should arrive tomorrow, so i will fit them and see what happens   


      Will also check my air gap inside the distributor at the same time.............. 0.008" I am reliably informed.

[Chryco Psycho]

do a compression test on #8 when you get a chance

[cudaneil]

   Hi, something else i noticed when my car is at idle with this pesky misfire.    The condensation out of the exhaust pipes, is only coming out of one side !!!


      The other side is clear..........................Does that point to something   CHRYCO ?           

[MEK-Dangerfield]

Do you have an "H" or an "X" type of exhaust system? Meaning the two long pipes cross-over and connect to each other. If so, then this doesn't tell us much. This probably only happens when you first start the car, right? Then it's normal.


   Mike

[FY1Cuda]

If you don't have a crossover for the tailpipes, then it points to a head gasket leaking.  My only experience with head gaskets was on a Chevy 327 and the two rear cylinders, 7 and 8, were the ones that blew.

[cudaneil]

   My exhausts do not connect at all ,they are seperate.  The condensation is only when the motor is cold and comes from the same side pipe as the misfiring cylinder.

    As far as i know, im not losing any coolant and dont have to top up. 

[340Challman]

When you pull the plug boot off, if you pull it away from the plug slowly does it start to hit on it then?

[Chryco Psycho]

I would think condensation is a poor indicator , , you really need to do a compression test wet & dry

[cudaneil]

I would think condensation is a poor indicator , , you really need to do a compression test wet & dry

              Fitted my new rotor arm and cap today and checked the air gap !    Started her up.............no difference.     

              Trying to borrow a compression  tester,  will check it at the weekend.

              Also had a look at my carb to intake manifold gasket today, its a bit old and brittle...........new one on its way to me !

              Maybe the carb gasket is to blame, losing vacuum   in the intake manifold        I hope so,its getting annoying now     

[340Challman]

When you pull the plug boot off, if you pull it away from the plug slowly does it start to hit on it then?

The reason I ask this is that I have the same problem on #1. I have changed everything electrical and still nogo. As I was saying, if I pull the boot away from the plug slowly it will start hitting on all 8. Compression - no, Cam - no. Increasing resistance on #1 will induce a spark.
So I was wondering if yours is doing the same.
 
Kevin

[cudaneil]

 hi, kevin i think mine is a different problem to yours. mine is not doing that.    Have you tried checking the air gap in your electronic distributor or points gap if the other type.


            Maybe yours is a weak spark,which could be coil, ecu box or ballast resistor.     

   I sprayed around my carb base gasket when at idle with a can of spray solvent and the idle improved,which points to the gasket leaking and affecting the vacuum in the

     intake manifold.

[340Challman]

hi, kevin i think mine is a different problem to yours. mine is not doing that.    Have you tried checking the air gap in your electronic distributor or points gap if the other type.


            Maybe yours is a weak spark,which could be coil, ecu box or ballast resistor.     

   I sprayed around my carb base gasket when at idle with a can of spray solvent and the idle improved,which points to the gasket leaking and affecting the vacuum in the

     intake manifold.

Thanks Neil, but unfortunately I have replaced everything electrical. Sometimes two and three times. I'm glad that you don't have the same problem because I am at a loss and everybody that I talk to says I need to replace something I have already replaced twice.
Good luck with yours. I'm sure you'll find it.
 

Kevin

[cudaneil]

   Kevin,  have you got the correct heat range plugs for your motor ?  Also have you had a vacuum gauge test ?    and checked your vacuum hoses for cracks etc !


           If your intake gaskets are drawing air it will give you a misfire .             Is your misfire only at idle ?            Neil       

[340Challman]

   Kevin,  have you got the correct heat range plugs for your motor ?  Also have you had a vacuum gauge test ?    and checked your vacuum hoses for cracks etc !


           If your intake gaskets are drawing air it will give you a misfire .             Is your misfire only at idle ?            Neil       

The miss is continuous at any rpm. I have checked everything and I am baffled. As I said, increasing resistance by pulling the boot away from the plug induces a spark and the engine runs fine on all 8. This indicates not enough resistance to cause the coil to charge. I have changed plugs & wires more times than I can count. Cap, rotor, coil. I put an entire MSD 6A system in. Still have the miss. This is part of the reason I am going to tear down the motor. I figure I will get it in the rebuild, because it is not electrical. At least I don't know how it could be.
My apologies. I didn't mean to hijack your thread. I was just hoping that you might have similar symptoms and we could figure it out between the two of us.

Kevin

[Chryco Psycho]

I assume you have replaced the plug , it could be arcing over the ceramic to ground