International2cvFriends.com :: View topic - �Missfire at idle (mainly)

Tim2cv wrote:

D*lly has recently started to miss fire at idle then fine if you dab throttle again or keep on high choke. under load she is also fine and still flys round the clock to over 70mph. no tapping, banging, scraping, pinking etc on a 200 miles round trip on saturday she flys under full beans but let off abit but not far enough to over run and missfire again regardless of speed, noticable mainly in that way by driving about 40mph floored in 4th then easing off... she will start to missfire. when missing at idle she tries to stall and of course is very lumpy.

I have fitted a new yellow coil, new plugs, air filter and checked and cleaned the carb, everything as expected. no visible carb block leaks and fuel filters clean. If i spray a light mist of carb cleaner in the carb revs pick up then die away again i assumed this is normal.

she is running on 123 and I dont use points

yuk!

Any ideas? :cry:

Van isnt ready for the road and the Xsara broke itself this morning again

Tim2cv wrote:

I have actually ordered a new 123 to eliminate that from the equation. I would rather be poor than struggle with points!

Quote:

I'd rather change an engine than change points!

oolong wrote:

Points are great! Tak less time than a 123 to fit. Just make sure they're not English-made. Especially good when combined with a Boyer Bransden electronic box. Never feel happy with 123 - had a friend's fail on a very wet night when points would have been - and were 100%, luckily he'd kept the points and weights etc, but a very unpleasant bit of 'maintenance'. Not even sure a 123 gives the supposed better performance - bit of a nice earner for the sellers, I feel. Great for those who leave the ignition on and engine stopped, though. And expensive diagnosis at £100+ when it probably does not even need replacement.

Heard of a car which ran ok but wouldn't idle properly - a fortune was spent replacing this that and the other until at last the DG unit was found to be faulty.

The fan still has to come off for maintenance, especially if you use your car through winter...

So don't completely rule out the 123, Tim.

By the way, have you had the carb off and blown backwards through the idle passage? (small hole on underside of carb). Sometimes really small pieces of crud can lodge themselves in these internal galleries and can only be removed the same way they arrived.

best, oolong

Author:	Tim2cv [ March 8th, 2010, 8:34 pm ]
Post subject:	Missfire at idle (mainly)
D*lly has recently started to miss fire at idle then fine if you dab throttle again or keep on high choke. under load she is also fine and still flys round the clock to over 70mph. no tapping, banging, scraping, pinking etc on a 200 miles round trip on saturday she flys under full beans but let off abit but not far enough to over run and missfire again regardless of speed, noticable mainly in that way by driving about 40mph floored in 4th then easing off... she will start to missfire. when missing at idle she tries to stall and of course is very lumpy. I have fitted a new yellow coil, new plugs, air filter and checked and cleaned the carb, everything as expected. no visible carb block leaks and fuel filters clean. If i spray a light mist of carb cleaner in the carb revs pick up then die away again i assumed this is normal. she is running on 123 and I dont use points yuk! Any ideas? Van isnt ready for the road and the Xsara broke itself this morning again

Author:	baron_matt [ March 9th, 2010, 5:15 pm ]
Post subject:	Re: Missfire at idle (mainly)
Tim2cv wrote: D*lly has recently started to miss fire at idle then fine if you dab throttle again or keep on high choke. under load she is also fine and still flys round the clock to over 70mph. no tapping, banging, scraping, pinking etc on a 200 miles round trip on saturday she flys under full beans but let off abit but not far enough to over run and missfire again regardless of speed, noticable mainly in that way by driving about 40mph floored in 4th then easing off... she will start to missfire. when missing at idle she tries to stall and of course is very lumpy. I have fitted a new yellow coil, new plugs, air filter and checked and cleaned the carb, everything as expected. no visible carb block leaks and fuel filters clean. If i spray a light mist of carb cleaner in the carb revs pick up then die away again i assumed this is normal. she is running on 123 and I dont use points yuk! Any ideas? Van isnt ready for the road and the Xsara broke itself this morning again Hi Mate Have you checked that the accelerator pump is working as it should? Also is your idle jet clear etc. Misfire could be due to ignition fault or fuel starvation. Have you fitted the coil etc to try and fix this fault? Or has it started doing it since? 123 working as it should? What volts are you getting at the battery?

Author:	Tim2cv [ March 9th, 2010, 10:06 pm ]
Post subject:	Re: Missfire at idle (mainly)
Accelerator pump is working fine (i think) if i pull it, it squirts ok, idle jet is clear (it think) a picture would confirm I have checked the correct item! i fitted the plugs and leads in the hope to clear the poor running but it made no difference. I have actually ordered a new 123 to eliminate that from the equation. I would rather be poor than struggle with points! D*lly never fais to start and the battery isnt very old really and cranks over with ease... lights dont flicker etc... Ordered a pair of carb gaskets and an insulator block incase i have to take the carb off.

Author:	Neil [ March 9th, 2010, 10:21 pm ]
Post subject:	Re: Missfire at idle (mainly)
Tim2cv wrote: I have actually ordered a new 123 to eliminate that from the equation. I would rather be poor than struggle with points! One of Tim's most famous quotes is: Quote: I'd rather change an engine than change points!

Author:	Sean [ March 9th, 2010, 11:01 pm ]
Post subject:	Re: Missfire at idle (mainly)
could be as simple as the idle mixture screw(co2) in too far back it out 1/2 a turn and see how it goes Sean

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Author:	ken [ March 9th, 2010, 11:31 pm ]
Post subject:	Re: Missfire at idle (mainly)
Tim, I reckon that Sean's on the right path in suspecting a weak mixture, but wonder if it's the carb base gasket which is at fault. It's not usually possible to _see_ any leaks in the carb base block, unless it's really fallen apart. The best test I've found is to use a small plastic oil can to drip petrol directly onto suspect areas, which include the intake manifold to head joints as well as the carb base. If the tickover becomes steadier, you know you've found a leak... < http://cgi.ebay.co.uk/PLASTIC-OIL-CAN-W ... 1601wt_754 > ken.

Author:	oolong [ March 10th, 2010, 2:30 am ]
Post subject:	Re: Missfire at idle (mainly)
Points are great! Tak less time than a 123 to fit. Just make sure they're not English-made. Especially good when combined with a Boyer Bransden electronic box. Never feel happy with 123 - had a friend's fail on a very wet night when points would have been - and were 100%, luckily he'd kept the points and weights etc, but a very unpleasant bit of 'maintenance'. Not even sure a 123 gives the supposed better performance - bit of a nice earner for the sellers, I feel. Great for those who leave the ignition on and engine stopped, though. And expensive diagnosis at £100+ when it probably does not even need replacement. Heard of a car which ran ok but wouldn't idle properly - a fortune was spent replacing this that and the other until at last the DG unit was found to be faulty. The fan still has to come off for maintenance, especially if you use your car through winter... So don't completely rule out the 123, Tim. By the way, have you had the carb off and blown backwards through the idle passage? (small hole on underside of carb). Sometimes really small pieces of crud can lodge themselves in these internal galleries and can only be removed the same way they arrived. best, oolong

Author:	baron_matt [ March 10th, 2010, 1:32 pm ]
Post subject:	Re: Missfire at idle (mainly)
oolong wrote: Points are great! Tak less time than a 123 to fit. Just make sure they're not English-made. Especially good when combined with a Boyer Bransden electronic box. Never feel happy with 123 - had a friend's fail on a very wet night when points would have been - and were 100%, luckily he'd kept the points and weights etc, but a very unpleasant bit of 'maintenance'. Not even sure a 123 gives the supposed better performance - bit of a nice earner for the sellers, I feel. Great for those who leave the ignition on and engine stopped, though. And expensive diagnosis at £100+ when it probably does not even need replacement. Heard of a car which ran ok but wouldn't idle properly - a fortune was spent replacing this that and the other until at last the DG unit was found to be faulty. The fan still has to come off for maintenance, especially if you use your car through winter... So don't completely rule out the 123, Tim. By the way, have you had the carb off and blown backwards through the idle passage? (small hole on underside of carb). Sometimes really small pieces of crud can lodge themselves in these internal galleries and can only be removed the same way they arrived. best, oolong Likewise I have found when stripping an engine down that someone had fitted the carb block the wrong way round so that the smaller primary hole restricted the secondary choke. Strange but true. I'm unsure whether to go points or 123 on the Ami. Since setting points on an Ami 8 is a total ball ache and a bit like wallpapering your hallway through the letterbox I may go down the 123 route.

Author:	Russell [ March 10th, 2010, 8:42 pm ]
Post subject:	Re: Missfire at idle (mainly)
... And never clean your oil cooler?

Author:	Tim2cv [ March 10th, 2010, 9:13 pm ]
Post subject:	Re: Missfire at idle (mainly)
after the gym tonight I set about trying to sort D*lly out... dissassembled her and removed the 123... fitted the new one and no difference. bugger... took the carb off and changed the paper gaskets, the insulator block was fine and looked in very good condition so i didnt change that. (gaskets etc correct way round BTW) re-assemble and quick test drive. Seems abit better but still not 100%. I only static timed her as i dont have a strobe but i did pin and use my marks frome previous work. had a quick twiddle of the mixture screw but it hasnt moved since ever and didnt seem to give an difference... will try and borrow a colour tune kit and strobe and check the timing and mixture soon. the idle adjustment screw seems to be almost all the way in and she still sttugles to idle, use the choke and often fine. Will give her a run from cold tomorrow to work and see how she really is then. cheers for the comments, any more greatly recieved!

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