Help. Rough and missing driving one minute, smooth the next?

[luvemfast]

Took the Z out for a short drive yesterday and it seemed to be missing, not on all cylinders, then would drive nicely.

Why would it do this?

I was thinking this morning that it could just be the dizzy cap.

Or could it be something else?

Will check the cap and plugs tonight.

Didn't seem to want to rev over 5,500 either.

 

All I have done is change the radiator over the weekend, it seemed happier/smoother/gruntier/better last weekend.

 

 

[RB30X]

I'd take a punt and say you've used a hose to refil the radiator and splashed water over the engine electricery. Park it in the sun for a few days and let it dry out. I washed my VL turbo once and woke up to a strange noise at 3am in the morning. It was my pop up calais headlight eye lids popping up and down due to moisture in the relay.

[luvemfast]

Yeah fair point, I was pretty careful when filling the radiator as I didn't want to get the garage floor wet 

Its a beautiful day here, so might dry it out if it is wet

[.]

One of the guys at Bathurst had a similar issue. It turned out that the plate that secured the Dizzy had broken allowing the dizzy timing to change freely. Check to see if the Dizzy can turn without undoing the screw.

[luvemfast]

One of the guys at Bathurst had a similar issue. It turned out that the plate that secured the Dizzy had broken allowing the dizzy timing to change freely. Check to see if the Dizzy can turn without undoing the screw.

I hope not, just had it rebuilt not long ago.

[Zedsabbath]

An oiled up plug can have that effect, also it's not unknown for plugs to be faulty from new...lift the plug leads off one at a time and listen for a change in revs,

other than that, when you remove the plugs look to see if one or more are blacker than the rest

 

[Zedsabbath]

Also look for a bad wiring connection in the ignition system

[luvemfast]

An oiled up plug can have that effect, also it's not unknown for plugs to be faulty from new...lift the plug leads off one at a time and listen for a change in revs,

other than that, when you remove the plugs look to see if one or more are blacker than the rest

Changed the rotor button and dizzy cap, cylinder plug number 1 looked blacker than the rest.

What would that mean?

[Zedsabbath]

" number 1 looked blacker than the rest. What would that mean?"

 

It means it's not firing adequately....change it or change all of them for new ones and keep an eye on that number one cylinder in case that happens again

If your plugs keep fouling, you might have a ring problem or worn valve seals

 

Pete

 

 

[luvemfast]

If your plugs keep fouling, you might have a ring problem

he he he he he     

[luvemfast]

Just had a thought about plug #1.

To fit my tiiming light, you take the lead of plug #1, fit the timing light to the plug then fit the lead on to the timing light. It fits in between the plug and lead, if that makes sense.

So could this have given me a black plug? I hope so....

[Zedman240®]

If the timing light wasn't flashing after you installed it that way, that would foul the plug. You may have a dodgy lead or like others have said a bad plug. Swap it with an older spare plug if you have one to eliminate that.

[luvemfast]

Light worked,

Could it lose some of the spark after going through the timing attachment?

You going tomorrow night Dimitri?

[Zedman240®]

Yep. I'll see you at the meeting.

[MaygZ]

Light worked,

Could it lose some of the spark after going through the timing attachment?

 

No.  the timing light uses VERY little of the spark power. 

 

Check out the below link for spark plug diagnosis.  Check the obvious things first.

 

http://www.spark-plugs.co.uk/pages/technical/diagnosis.htm

 

This one has clearer pictures:-  http://www.denso.com.au/Products/Aftermarket-Automotive-Components/Spark-Plugs/Diagnosis-of-a-Used-Spark-Plug

[zaxzeds]

Hello, before starting the engine try pulling the insulators on the leads back at the plug end to expose the metal connectors but leave them joined to the plugs. Start the car and grab one lead at a time at the thickest part of the insulator (to reduce chance of shock,dont worry it wont damage you) and gently disconnect  it from the plug observing the spark arc upto 4-5 mm between the plug end and the lead, (as you lengthen the spark gap it draws more spark to that plug and this will often allow a plug to fire when it wont fire while connected), and then move it closer to the engine block and watch it arc to the block. repeat this listening to any change in the engine,(better with a higher,constant rpm),dial up the idle screw or just open the thottle at the linkage. This should isolate the problem  cylinder and then just dry all the connections, then some water dispersant(wd-40,inox). If pain persists start changeing plugs around to isolate if it is spark supply or plug. N.B. if points or other electrical parts are a bit tired they will tend to give up when placed under a bit of extra strain like earthing though water etc.

  Good luck, cheers

[luvemfast]

Went out this morning to play with the car.

Was going to change the jets in the carbies and what did I find?

One of the main jets had come loose and was sticking up quite a bit.

I changed the jets (making sure they were all nice and tight), reset the timing and played with the idle and its running sweet again.

think I found the problem