The Triumph Dolomite Club - Discussion Forum

Not a new topic per se but maybe somebody can shed some light on my problem. My Sprint has the MKT0007 Lumenition system and has been in for about 6 or 7 years although my mileage is less than a couple of hundred a year now. I think the advice I was given at the time was to fit a new Lucas DLB 105 coil. This I did and everything was honky dory until about last year. I am now getting a fairly persistent misfire/jerking at anything over idle speed when the engine is under load which worsens if accelerating. I have got new NGK plugs and the timing set at about 10 degs BTDC ( I say about as the timing mark dances fractionally with the timing light illuminated but generally is between the 8 and 12 points on the timing plate). A local mobile auto mechnic who races older cars (the Sprint era) has checked the system over (compression is good on all four cylinders) but apart from saying I should methodically replace old for new in the ignition. He isn't sure on why this is happening. He suggested I use 97 octane fuel which I did and this made a big improvement but didn't sort it fully. I filled up with fuel at the weekend but failed to check the octane and put in 95 octane. The problem has returned and deteriorates when the engine has reached it's normal running temperature. I've noticed for some time that my coil is exceptionally hot to touch after only say a 30 minute run. Have any others with these items fitted experienced this or is the coil the problem?

The DLB 102 is a ballasted coil. If you wired it up to be ballasted still it should last a fair while, but I have had 2 oldish DLB102's go down on me, which made a misfire diagnosis a pain, as I swapped one failing coil for another.

If your system is now wired unballasted then your coil will get overly hot and will eventually degrade and fail.

I suggest a Bosch blue or Denso coil from a scrap micra. Neither of these has ever let me down. The Bosch blue is designed to be un ballasted, so run it and the feed to your magnetronic from your ignition fed fuse unfused side.

Jonners

Just corrected my original posr...the coil is a DLB 105 -not a 102.

Would your suggestion still apply to my amended DLB 105 coil Jonners?

Fit a red Accuspark:
http://www.accuspark.co.uk/coils.html

Fitting guide:
http://www.accuspark.co.uk/fitting_guide.html

DLB 105 is non ballasted.

Should run at full voltage.

Jonners

OK. Just bought a new Bosch coil (0221 119 027) fitted it and took car out for a test. NO CHANGE to problem - car hesitating at low/med speed when engine warm but more severe (almost backfire) when trying to acelerate harder. gŕrrrrrrr!!! Wiring is: red magnetronic lead to + coil, black magnetronic lead to - coil, pink/white ballast resistor wire and yellow (?)/white lead both disconnected. Slate/white lead to - coil. Lead from right hand side upper terminal of fuse box to coil +. Timing set for 10 btdc. 97 oct Texaco fuel (fresh). Any new ideas? My hopes of driving the Sprint up to Stafford tomorrow diminishing rapidly!!

Forgot to mention new NGK BP6EFS plugs fitted less than 200 mile ago and gapped at about 30 thou. The new coil is still really hot after about 45 mins test drive.

There is your problem...the NGK plugs...only 200 miles ago and the problems all recent?

Refit your old plugs if you still have them.

Try and find a set of Bosch platinums. The unipart plugs are ok to...mostly Bosch made but not platimums.

It is most unlikely both a Bosch blue coil ( I assume you got a blue - if its red run it ballasted and all may be well.)

Jonners

Thanks Jonners. Have had the NGKs fitted for about a year but thinking about it I think the problem may have started about then albeit less severe. What is it about the NGK plugs that is wrong? I took it from some posts on here a while back that they were fine! Yes, the Bosch coil does have a blue label on it and it says "High Energy Ignition Coil" 12v - and is made in Brazil.

Most will disagree with me and have before but I just immediately chuck anything made by NGK that looks like a spark plug
in the skip. I refuse to even keep them as spares...utter shite honestly. Maybe too many bad experiences...
Like a wasted afternoon at Reg's once...new NGK's wouldn't even start!

Champion used to be ok but I had a few Sprint plugs blow electrodes clean out so its Bosch only for me now.

Jonners

Yellow Banana wrote:Thanks Jonners. Have had the NGKs fitted for about a year but thinking about it I think the problem may have started about then albeit less severe. What is it about the NGK plugs that is wrong? I took it from some posts on here a while back that they were fine! Yes, the Bosch coil does have a blue label on it and it says "High Energy Ignition Coil" 12v - and is made in Brazil.

Did you not bother to read the link I posted where someone had the same problem as you and it was the wrong coil and too much resistance and the following post from Matt which states its the wrong coil, 100%.
(we are lumenition agents at work)
Optronic will NOT work happily with a Sports coil, which is what a DLB105 is. The primary resistance in the coil is wrong, and it will cause the coil to overheat and eventually fail.
You need to be using standard coil, i.e. a DLB101 if you have bypassed the ballast, or a DLB102 if the ballast is still connected.
I doubt the module is faulty, they normally work or they dont, but if you are worried you are welcome to send the module to me and i will test it on our Lumenition test rig, free, just pay the return postage.
Thanks - Matt.


Also been using NGK'S for years with no problems

Joiners you are a wizard!!!!! Just come back from a 45 min hard hilly fast drive (on dual c/way too) and only just one very minor hiccup after changing plugs to new Unipart gapped to 30 thou. Coil is still quite warm but not very hot as reported previously. Do all coils heat up?

Mahoney - did read the post, thanks but my system is a Lumenition Magnatronic not Optronic. Have ditched my DLB 105 for the blue Bosch.

Thanks all for your (oft confusing/conflicting) advice. Nice to know there is a big pool of info out there.