2 replies to this topic

[REDICE]

So I had a misfire for ages which has recently been fixed.  I thought I would share the experience.

It sounded like the car was starving for fuel. I checked out the fuel pump which had good flow. I got the carb (HIF44) rebuilt. It was running way to rich as well. The misfire went away about 10 min after the temp came up which meant taking the car to work was a real pain until the last km (and then looked stupid when I left for home). There was also much popping and banging whilst the car warmed up when applying the throttle. I was starting to think maybe the bi-metallic strip inside the carb was on the blink.

The problem was the battery and more precisely the alternator. If you have an electronic ignition module in the dizzy these take a lot of current to run correctly, so the car started to run ok once the battery had built up a good charge. You might experience this sort of misfire especially if your car is not a daily driver. Even though the battery could still start the car, it didnt have the required current. After a new battery the car ran great from the get go, although one night in a slow crawl up the main drag with many crazy traffic lights, the misfire returned until I got out on the motorway and gave it a good blast. After checking the alternator it was only putting out 13.2 V. Swapping it out for a spare I had that put out 13.9V  greatly improved the car's behaviour. Im also going to install a battery isolator.

After a good tune the carb delivers good power and the fuel economy has also been a pleasant surprise. 

Hope this helps to prevent tail chasing and many swear words with your fuel system. 

 

 

[sonscar]

Although it appears to have fixed your problem I think there are other things at play.The module itself takes little power as all it does is switch the coil to earth.It may misbehave if the voltage drops below 10 v.The coil takes about 3 amps when running so not excessive compared to the headlamps.You may still have other issues masked by the extra electricity supplied.
Of course I could be wrong.Enjoy,Steve..

[floormanager]

I had two annoying misfires. The first caused me a lot of fuss - new points, the heel of the points had worn and lost the gap.  As the points and condenser were new and set by the Distributor Doctor, I discounted them,

 

The second one I spent ages trying to get to the bottom of it. Plugs, leads, checked points again, low tension leads.  I finally found out what it was.  The rivet that fixed the lucar terminal to the +ve on the coil was loose.  As I drove along, it would move and momentarily, cut the power.  Grrrrr