17 replies to this topic

[Sweep16]

Evening All,

 

I have a 1986 998 A+ Mini Mayfair.

My first Mini and I've had it just over a year now, first winter it was fine but came off the road over the summer to have some MOT welding done, since then it has never quite run right, like it's misfiring but on all four cylinders.

 

So far it has had the following checked/adjusted/replaced, fuel mixture, timing, valve clearances, carb flange resealed (air leak), new fuel pump (fuel leak), plugs (correctly gapped), rotor arm, cap and HT leads. It has also had a compression test all four cylinders were 150-160.

 

Now the previous owner fitted an Accuspark conversion kit with a standard coil and at first I thought it had the wrong coil as the car should have had a ballast ignition system, this led me to believe that the coil was possibly producing a weak spark. I have since learned from him that he removed the ballast wire at the same time. However having read KernowCooper's previous post about converting to standard coils I think that the 12V feed has been done wrong as there is no clear wire from fuse 1 to the coil +.

 

There is however a red wire which comes from the + on the coil and joins up with the original white/yellow wire to the starter solenoid and a "mystery" brown wire out of the same section of loom (I will add a photo as soon as I figure out how).

 

My next step is to test the voltage going to the coil but in the meantime my questions are:

Would this arrangement likely result in insufficient voltage to the coil (especially when ancillaries running)?

What is the brown wire connected to the white/yellow wire?

Would disconnecting the red wire from the coil + and connecting a proper feed (as per KernowCooper's instructions) have a detrimental effect on something else?

 

All other electrical elements seem to run fine and the battery always holds a good charge, I have tested the coil before and it seems to be okay but I could be wrong.

 

Thanks in advance.  

 

 

 

 

[timmy850]

The first things I'd check are:

The ohm rating on the coil - using a multimeter set to ohms check the resistance from the + to - side of the coil

The distributor module brand and type. 

 

When the key is on check:

Voltage from the positive side of the coil to an earth like the engine block

Voltage on the red wire to the module 

[Steam]

As it was running fine before the coil will be the correct one. I would suggest the accuspark module has failed. The welding may be responsible for this. The easiest way would be to fit a new module but points would also prove the fault.
The coil and ignition are not fused.

[bpirie1000]

I would also ask who did the checking /adjusted/ replacing of the bits also who was it that you used to check the fuel mixture, timing, valve clearances, carb flange resealed (air leak), ?

Which plugs are you running?

Which carb needle are you running?

How old is the fuel in the tank, have you got an in line fuel filter?

What is the condition of the earthstraps? If the spark a good strong spark?

[Sweep16]

Okay run a few more checks today and the coil has 3 ohm resistance across + & -. There's 12v getting to the coil and 11.2v from coil earthed with ignition on. So regardless of whether it's wired correctly or not it is getting a good feed.

Car has good fresh fuel and it's run daily so it's not like it's sitting around.

I can't for the life of me remember which needle it's running at the moment but I have an AEM and an AAU in the garage and I do know the current needle is the leanest of the three (will try and check tomorrow).

Probably should have said before it has an HIF38 & a stage 1 exhaust but standard air filter and box (think the previous owner ran out of money).

Plugs are NGK BPR6E.

Edited by Sweep16, 11 February 2024 - 07:43 PM.

[cal844]

How old are the spark plugs? NGK plugs are scrap if they're doused in fuel

[Sweep16]

They've been changed within the last month. But the running was the same before and after.

[madalicesdad]

How old are the spark plugs? NGK plugs are scrap if they're doused in fuel

Why scrap? Why just NGK?
Just interested

Edited by madalicesdad, 11 February 2024 - 09:21 PM.

[cal844]

How old are the spark plugs? NGK plugs are scrap if they're doused in fuel

Why scrap? Why just NGK?
Just interested

I think it breaks down the core of the plug somehow, all I know is an NGK plug doesn't run right once it's been doused in fuel, even once one burns or evaporates the fuel

[Sweep16]

Is it likely to make much difference if I switch back to the Accuspark AC9CR three prong plugs?

[Sweep16]

So, removed the Accuspark module and reverted to points today, instant improvement. I guess it was the module on it's way out hence why sometimes it ran fine.

[bpirie1000]

Did you move the timming when you installed the accuspark?

Or get things checked over?

[Sweep16]

Yeah one of the guys at work (who's more clued up than me) tweaked the timing for me. He's going to bring his timing light in and do some fine tuning.

[Earwax]

Good to hear it is improved.  

 

Just to tag onto some ideas mentioned in this thread

:

Firstly

Spark Plugs -becoming too wet and then unserviceable I agree with this and have seen it in today's standard/premium fuel compared to leaded fuel (AVgas). I am not sure if just NGK either but does anyone know what the culprit is?

 

Secondly

Welding of Car -causing havoc with unfused electricals ( accuspark : Coil ) -  again i agree with this :

 

My question is to avoid this would you remove the coil/accuspark/and or disconnect both feeds or just remove earth wire or just either wire. - is the condensor also vulnerable? 

 

Curious

[Steam]

Or just forget the unreliable "in dissy" modules as they are the most likely cause of roadside breakdowns.
Go with points and if you desire dwell control look at sparkrite.