Ignition problem with my Pickup

Post by **Pikey** » Mon Jun 29, 2009 8:04 am

Hi all
I wonder if anyone can help me with regards to a problem with the ignition on my Pickup. Basically I have an intermittent misfire and she runs on a little. The misfiring is getting a bit annoying and Ive replaced, the points/condensor, dist cap, rotor arm, HT leads and plugs and she still occassionally misfires when pulling away from junctions. I have had a go at replacing the original Coil, but when I fitted a new one it gave me no power what so ever and the misfiring was a lot worse and she was backfiring. So Ive put the old one back on and all is fairly well again except for the occassional misfire.

The new coil I used was a new unit from my local motor factors and I think it must have been the wrong type as it made matters worse and it did get very hot to touch, so perhaps it was meant to run with a later type ballast resistor maybe?

Ive got what feels like good power and theres no signs of pinking etc, but she does run on slightly

Now this sounds to me as if my timings out slightly but Ive statically set it to 5BTDC with a bulb across the LT wire so I would say the timing is pretty bang on the button.

Forgot to say that Im running on an ordinary leaded head and use Castrol Valvemaster. And Ive checked the valves clearances and all is well, if not slightly rattly, certainly not tight anyway. Also when I rebuilt the engine about 8 years ago all I could get at the time was flat top 30thou o/s pistons and I fitted them, so my compression ratio is probably higher than it should be.

Should I give the Valvemaster plus a go. Its supposed to have a higher octane, perhaps that will stop my running on?

Im fairly sure my timings incorrect but, Ive made sure that its set right, can anyone advise on what it should be now Im running on unleaded.

Steve B

Post by **mike.perry** » Mon Jun 29, 2009 10:51 am

The ignition side of the car is probably OK. Check the timing is correct, adjust the dizzy to fastest tickover and fine tune on the vernier adjuster. Check the vacuum advance and then adjust the carb mixture if necessary. Also check that the carb piston is dropping correctly and it has 3 in 1 oil in it.
Have a look down the plug holes with a torch to see if there is any carbon build up as this can continue to ignite and cause the engine to run on.

Must get shares in 3 in 1 with all the recommendations its getting

Post by **bmcecosse** » Mon Jun 29, 2009 10:25 pm

What spark plugs are you using ?

Post by **Pikey** » Tue Jun 30, 2009 7:49 am

Many thanks for your replies.

I cleaned and flushed the oil in my dashpot last night. To be honest I dont know what grade was in there, its just what evers in my oil can, which I think might be castrol Magnatex 10w40 at the moment. I tip the left overs in my can from when I do my MX5 oil changes.

So my Dashpot has now got 3 in 1 oil in it. I'll have to test drive it not to check to see if its made a difference. It certainly lifted slightly easier to the finger tip.

My vacumn advance isnt very old I would say its about 6 years old ish, but I'll double check thats working.

My plugs are champion N9Y. They were NGK's but when I serviced the engine this spring I changed them hoping to solve this stutter, but its made no difference at all.

I also pulled a plug out last night too and the piston was fairly ish clean, When I say fairly ish clean, it wasnt oily or anything nasty and it wasnt shiny alloy either it just looked dull sooty grey. The spark plug was quite black so I think shes probably a bit too rich.

Should I get another coil, I very much doubt the one Ive just bought was the right type.

Just one more question, sorry, When I changed my coil over to the new one and made matters a lot worse, what would have happened if I had done silly error with the +/- being on the wrong way around. Just not have started. Im conventional Positive earth.

Many thanks

Steve

Post by **bmcecosse** » Tue Jun 30, 2009 8:28 am

Coil connection does make a slight difference - it's obviously better the right way round - in your case (not many cars are stil +ve earth!) the + connection should go to the dizzy. I'm very surprised it ran worse with the coil - unless they somehow gave you a 24 volt coil. The Mini coil is intended to run on ~ 9 volts, and so on a 12 volt car it gives great sparks - until it burns out. This may be the clue of course - great sparks finding a path to earth through some break-down inan electrical component. You seem to have replaced just about everything - but often the little 'low voltage wire' inside the dizzy is overlooked - check it carefully. Otherwise - suspect the rotor arm - refit the old one and try - the new ones sometimes seem to be troublesome.

Post by **Pikey** » Tue Jun 30, 2009 8:43 am

Hmm. Ive got a spare dizzy on the shelf, so I might put a shot in the dark and fit that. As you say I never know something might be shorting out within my dizzy and my old coil isnt producing a strong enough spark to make it a problem, with this new coil, the insides on my current dizzy might be like a fireworks display, hence the terrible running and backfiring etc. I'll swop just the rotor arm and dist cap over with old genuine lucas first just to eliminate things and let you know.

Many thanks

Steve

Post by **bmcecosse** » Tue Jun 30, 2009 8:51 am

That's the idea - although spare dizzy is best kept in the car - not on the shelf!

Post by **Pikey** » Tue Jun 30, 2009 9:15 am

Just looked at ESM I think Im going to bite the bullet and get an recond exchange distributor. Their cost isnt quite as bad as I thought £52 plus my old one. That'll sort it out once and for all.

Many thanks for you help, I'll let you know how I get on.

Regards

Steve B

Post by **bmcecosse** » Tue Jun 30, 2009 9:27 am

Try the old spare one first! It will be one small thing - you don't need a whole reconditioned dizzy!!

Post by **Pikey** » Sun Jul 05, 2009 7:44 pm

Firstly many thanks for the replies to my problem regarding the misfiring on my pickup.

Not sure what exactly was causing the misfiring, but Ive only replaced the new dist cap and the rotor arm to units from an old distributor that I had spare. And thats seems to have sorted it.

Also the 3in1 oil in the dashpot makes her act like a completely different car, the acceration seems so much smoother and not a jerky as it was before, also when I pull up to a stop, the engine is no longer trying to stall when I lift off. So thats sorted too.

The only other thing I noted when I was messing around under the bonnet, was that the fuel pump didnt stop ticking when the pressure was reached in the pump/carb (engine off). So I came to the decision that although I was lifting fuel and it was filling the float chamber something was leaking pressure and not letting the pump stop. So with no obvious leaks from the carb I dismantled the pump cleaned both of the flutter valves and now the pump stops as it should and thats all sorted too.

Perhaps my misfire was something to do with the dist cap/rotor arm, but it may also have been the dashpot oil or the fuel pump was'nt suppling demand due to a leaky valve even at tickover.

I attended a local show on saturday and she didnt miss a beat, great.

Oh one other thing, I tested the new replacement coil with an ohm metre, I guessed that my HT circuit should be around 4K ish ohms, (from when I check stationary engine mags) and so this coil should around the same. And would you believe it, it registered nothing and just to double check the situation I checked my old working coil and that was 5.3K ohms. So that confirmed it, my new coil was dead. Im suprised it worked at all actually with an open circuit on the HT side. So needless to say my new coil will be going back to the motor factors tomorrow.

Anyway many thanks to all.

Regards

Steve B

Post by **bmcecosse** » Sun Jul 05, 2009 9:33 pm

Well done ! Would be interesting to refit the 'new' dizzy cap - and the 'new ' rotor arm, one at a time - and see if the problem returns. And if it does - which item is the culprit!!