misfire

[Yorkkie]

Hello the worldly wise,

 

drove the car (CR960) 100 miles or so on Monday..... fantastic going like a train and never missed a beat. Just on the way into my house a very slight cough and missfire. I put this down to heat soak as we had been in some traffic for 20 mins or so.

 

Drove the car the next morning on a short journey all was fine no missfire......

 

Came to drive home in the evening.. car started fine, within 200yrds severe missfire. Characteristics of the miss was not coughing and spluttering rather a sudden chop for 0.5 second then fully back on song. I continued to drive the car home with this miss getting more frequent... full power to nothing and back (drive train stood up well no severe cluncking from diffs or UJs). Eventualy stopped a few hundred yards from home. After 5 mins or so restarted but exhibiting same severe miss, it drove for another 100yds or so and stopped altogether, continued efforts to start it flattened the battery so that was that.. So close to home.... so I got a short tow and put it in the garage as I was out to dinner that evening.

 

Came to it yesterday, it fired first time running smoothly. I left it for 20 mins to heat up no sign of a miss, Heated up the coil with a hair drier to very hot! still no miss.

 

I measure voltages around the system as it was running Battery 13.9v top of coil 12.4v bottom of coil 9.4 or so.. These number sounded ok to me . I had a spare capacitor so I changed that just in case. I then inspected the wire from the bottom of the coil to the dizzie. I noticed it had a small nick in the insulation which was slightly blackened around the edge, right on a tight bend in the middle of the 35cm bit of wire . Now my assumption is that this could have touched the block intermittently and cause the severe miss.

 

I am making a new one in silicon insulated wire today and will try tonight.

 

Anyway I hate not finding something really conclusive, does anyone think of anything else I should check.... I might even put the bad wire back in the dark and see If I can see it sparking.

 

Regards

Andy

[Lee Sellars]

Hello Andy

 

Have you checked the petrol filters and you may have a blocked Injector. Same symtoms.

 

Lee

[88V8]

Totally cutting out does sound like ignition. I'd say you've probably found it.

 

If you have a ballast coil, might be the ballast.

 

Ivor

[Mike Collins]

Sounds similar to my last rotor arm failure, is yours old or new red type?

 

Mike.

[Yorkkie]

I havnt checked the ballast.... maybe I should switch to direct 12v . My rotor arm is black and I have to say the brass insert does move withing the rotor arm itself (not impressed with the quality. So maybe I will buy another one at the same time as the coil. How does the rotor arm fail?

 

I havnt looked at the fuel filters. I would have expected more spluttering and choking if it was fuel, the effects I suffered were quite instant on- off - on - stop.

 

So now I need to search for best coil and rotor arm supplier>........

 

Andy

[Mike Collins]

Andy, I have two failed rotor arms on the bench. One was a dead stop and you can see carbonisation where the insulation has failed under the spring clip. It shorts the HT to the spindle. The other has no visible failure but started as a loss of power after gear change, rapidly worsened to random power loss, backfire and dead stop.

 

Both on different cars within a month or so.

 

The consensus is try to get a red one.

 

Mike.

[Yorkkie]

Andy, I have two failed rotor arms on the bench. One was a dead stop and you can see carbonisation where the insulation has failed under the spring clip. It shorts the HT to the spindle. The other has no visible failure but started as a loss of power after gear change, rapidly worsened to random power loss, backfire and dead stop.

 

Both on different cars within a month or so.

 

The consensus is try to get a red one.

 

Mike.

 

 

Thanks Mike....... well I never did where do I get a red one from?

[jd6]

Distributor Doctor does the red ones

 

Jules

[Alec Pringle]

From Martin Jay

 

http://www.distributordoctor.com/red-rotor-arms.html

 

Cheers,

 

Alec

[Yorkkie]

From Martin Jay

 

http://www.distribut...rotor-arms.html

 

Cheers,

 

Alec

 

 

 

 

 

Thanks Alec... I will get one ASAP

 

cheers

Andy

[Yorkkie]

Anyway......

 

I bought a DLB105 12V sports coil a new dizzie cap and rotor arm... I replaced the wire from the dizze to the coil.

 

When fitting the new coil I ran in a new wire from the ignition direct to the coil. I then noticed that the coil I have taken off is also a DLB105... Assuming that they dont use the same type number for ballast and unballasted coils then I have a 12v coil operating on a ballasted system. It ran very well until this last fault. I am sure it is a ballasted system as I can measure 1.8 ohms from the ignition to the coil and a voltdrop at the coil when running of around 3 volts

 

Anyway now is a 12v sports coil running on 12v . What should I set my plug gaps at, I have been using 30thou up to present.

 

And next points replacement system but which one?

 

Regards

Andy

[Yorkkie]

So, I replaced the points with a Powerspark (from SimonBBC on fleabay). It was difficult to set the timing staticaly with a bulb . Indeed when I first started it the car was very retarded against the strobe. The device was very easy to fit, and can revert to back to the old points easily. I set the timing with the strobe to the same mark as before.

Starting is really good and the car seems to pull much better, probably because I have 12v to a 12v coil now.

 

I have now advanced the timing a couple of clicks and it is even stronger. I intend to keep up this process until the car has any tendency to pink. I will then know the extreme and back it off.

 

30 thou plug gap seems ok.

 

Andy

[rpurchon]

So, I replaced the points with a Powerspark (from SimonBBC on fleabay). It was difficult to set the timing staticaly with a bulb . Indeed when I first started it the car was very retarded against the strobe. The device was very easy to fit, and can revert to back to the old points easily. I set the timing with the strobe to the same mark as before.

Starting is really good and the car seems to pull much better, probably because I have 12v to a 12v coil now.

 

I have now advanced the timing a couple of clicks and it is even stronger. I intend to keep up this process until the car has any tendency to pink. I will then know the extreme and back it off.

 

30 thou plug gap seems ok.

 

Andy

 

i had one of those electronic jobbies from simon bbc.it only lasted a couple of months.

it started missing couching farting backfiring for a mile,then died.

hope yours is ok.but keep your old points and condensor in the boot just in case.

richard

[Edwin]

 

.......It was difficult to set the timing staticaly with a bulb......

 

Andy

 

Hi Andy,

 

I also just bought one from "Simon BBC" and can't seem to get the static timing method working. I'm assuming it's the same as with points: put a bulb between the (+) terminal of the battery and the (-) wire of the module. But the bulb doesn't light up.... maybe I got the connections mixed up or something like that....

 

How did you connect the bulb and wires of the module to get this method working? Right now I can only use the static method: my strobe is with a friend of mine and will not get it back before next weekend....

 

Cheers,

Edwin

[Yorkkie]

I connected the bulb across the coil. the same as you. I found I had to use the gap adjusting screw to move the trigger unit closer to the rotor to get it to fire. Indeed in principle it is the same as setting timing with points but.......

 

The device fires quickly and wont stay fired, rather it fires in a pulse when triggered, points on the other hand stay open and closed and the bulb is light much longer.

 

I found it too difficult to set staticaly and ended up with the timing very retarded using that method....

 

Also you need 12v at the coil it wont work with a ballast system (1.5ohm coil).

 

Regards

Andy