Missing under load and when cold

[JoeBeta]

I have an intermittent problem which I am putting down to the ignition system.....  But I am open to suggestions!!

I have a beta coupe 1.6, which has the bosch electronic ignition.

It has started to miss, splutter under acceleration. Feels like missing on 1 sometimes 2 cylinders??
And will miss through the whole rev range.  A couple of times I have had the full blown backfire down exhaust and a complete stop.

I have replaced the usual suspects (cap, rotor, leads etc), Was ok for a day then does the same.
I have played about and if i have it sitting on idle while I play about with ignition / carb (stripped and cleaned carb) etc and it gets hot, it will then run OK and drive like a dream.   As soon as it cools down the missing and spluttering returns.

So I have had it running perfectly a few times but as soon as it is left to cool down it will miss again.

The times when I have driven from cold, it will start to run Ok when it gets upto full temp (but not all the time)

any suggestions comments would be appreciated.

thanks

Joe

[rossocorsa]

have you taken the carb off the car and blown through everything using an air line with the jets and mixture screws removed? If not try it as this may well clear some small particles had this on a 1600 berlina and that was the cure. 

[JoeBeta]

Hi thanks for reply,  Yes the carb has been removed and stripped and blown out with airline.
I also checked the gaskets onto the manifold.

This really feels elcectrical (but I could be wrong)

[rossocorsa]

I'd just try checking and cleaning all the electrical connections under the bonnet. I use this stuff for protecting them from the weather

http://www.contralube.com/

[MattNoVAT]

I had a similar issue with my first Hawk Stradale which had the ECU lifter from an Alfa 164, it would itermittently misfire and generally run like a pig. Eventually I found an earthwire that was fatigued and would sometimes not form the connection, chopped out the bad wire, replaced with new and cleaned up all earths that I could find.  Never happened again after that.

I agree it sounds electrical, as sometimes its fine. 

If you can get it to run fine then go round and wiggle all the wires you can find and see if anything changes the running.

[75coupe]

Hi,

I had an intermittent misfire and occasional die altogether problem on my 2L coupe with bosch electronic dizzy and turned out to be the coil breaking down. had a plug out and earthed against body - would generate a spark but once under compression pressure in the engine, spark was not powerful enough to jump gap.

[JoeBeta]

Thanks Guys,

Will have a bit of tinkering to do at weekend.  See if I can track down a coil to test with also?

cheers

Joe

[Spyder79]

What area are you in?

I have a spare coil in my boot and am in Woking in Surrey if you would like to try it.

Mike

[JoeBeta]

Thanks Mike,

But I am in Aberdeen, North Scotland, so maybe a bit of a journey??

Do the Montecarlo's have a compatible coil??  I know of one of those locally.

cheers

Joe

[WestonE]

Joe

Look very closely at the fine wires from the distributor at the Dizzy and at the connector plug to the black box. Are they breaking leading to high resistance? Also try a spare ignition switch as the contacts burn inside the switch adding random running issues.

Eric
PS look at each HT connector in turn. You do not want any corroded or loose HT Leads/ cap or coil terminals. 

[JoeBeta]

Thanks for the help guys, this one has been annoying me for a few weeks..

The fault was indeed the coil....  I brought a new one from my local motor factors,  and miss fire problem has disappeared..
Think I am safe to cheers after 4 days testing

Joe