Jump to content


Photo
- - - - -

Help Hi Hc Emissions


  • Please log in to reply
17 replies to this topic

#1 Loco69

Loco69

    Learner Driver

  • Noobies
  • PipPip
  • 21 posts
  • Location: Aylesbury

Posted 18 October 2019 - 08:31 AM

Hi
Mini I’m talking about is a 1982 mini 1000 only mod is a cone air filter

Hope someone can help I’ve recently decided to get my mini back on the road I’ve changed her head gasket and taken her for an MOT where she failed on high co emissions so I brought her home about 2 miles from the garage and turnt the adjuster a couple of turns to make her run a bit leaner.

I then took her for a re-test and the co is now ok but the hc emissions have jumped from 500ish to 6000 I’ve tried adjusting the carb but it’s made no difference and the guy at the local garage is at a loss. Any ideas of what this could be would be greatly appreciated.

Many thanks in advance

Andy

#2 unburntfuelinthemorning

unburntfuelinthemorning

    One Carb Or Two?

  • TMF+ Member
  • PipPipPipPipPipPipPip
  • 1,224 posts
  • Location: Bedfordshire

Posted 18 October 2019 - 09:07 AM

Check the plugs.  They may have fouled up due to running rich and could now be misfiring. 



#3 Loco69

Loco69

    Learner Driver

  • Noobies
  • PipPip
  • 21 posts
  • Location: Aylesbury

Posted 18 October 2019 - 09:12 AM

Have cleaned them and no improvement..: could it be the valve clearances or timing have slipped?

#4 Icey

Icey

    One Carb Or Two?

  • Traders
  • PipPipPipPipPipPipPip
  • 1,171 posts
  • Location: Wiltshire

Posted 18 October 2019 - 09:15 AM

Have cleaned them and no improvement..: could it be the valve clearances or timing have slipped?

 

Neither will cause high HC and timing is on a chain, if that's slipped you'd have bigger problems.

 

A couple of turns of adjustment is too much. You should do it quarter or half turn at a time with the emissions reader attached to the car. If the MOT station is reasonable they should let you spend a few mins getting it right.

 

Also make sure your idle speed is correct, I've had a couple of incidents where a marginal car has passed by tweaking the idle down a few RPM where it was a little high.


Edited by Icey, 18 October 2019 - 09:16 AM.


#5 Loco69

Loco69

    Learner Driver

  • Noobies
  • PipPip
  • 21 posts
  • Location: Aylesbury

Posted 18 October 2019 - 09:21 AM

Have tried adjusting carb at the garage while on the emissions machine but can get the co to 3.5% but the hc is still around 6000. Took her for a run to warm her up and she feels low on power that’s why I wondered if the distributor had moved or the valve clearances had altered

#6 unburntfuelinthemorning

unburntfuelinthemorning

    One Carb Or Two?

  • TMF+ Member
  • PipPipPipPipPipPipPip
  • 1,224 posts
  • Location: Bedfordshire

Posted 18 October 2019 - 09:30 AM

It's possible for the ignition timing to slip if the distributor clamp is loose.  Anything that causes a misfire will raise the HC emissions quite substantially.  I'd be suspecting something to do with the ignition system if the carb idle mixture is ok. 



#7 Icey

Icey

    One Carb Or Two?

  • Traders
  • PipPipPipPipPipPipPip
  • 1,171 posts
  • Location: Wiltshire

Posted 18 October 2019 - 09:35 AM

Have tried adjusting carb at the garage while on the emissions machine but can get the co to 3.5% but the hc is still around 6000. Took her for a run to warm her up and she feels low on power that’s why I wondered if the distributor had moved or the valve clearances had altered

 

Apologies, you're quiet right, I was thinking cam timing not ignition timing for some odd reason. So yes it's possible an ignition timing change may throw emissions out. First is simple checks like vacuum advance is connected/no leaks and then to use a gun to check the static timing.



#8 DomCr250

DomCr250

    Super Mini Mad

  • Members
  • PipPipPipPipPipPip
  • 580 posts
  • Location: Berkshire
  • Local Club: 16V mini club

Posted 18 October 2019 - 09:55 AM

Is it still on points or have you fitted an electronic kit - at £40 ish it's worth fitting if you still have points.

 

High HC is normally a sign of poor ignition, so plugs, timing, spark, coil are all possibilities.  



#9 Loco69

Loco69

    Learner Driver

  • Noobies
  • PipPip
  • 21 posts
  • Location: Aylesbury

Posted 18 October 2019 - 10:12 AM

Yes fitted with accuspark electronic ignition

#10 DomCr250

DomCr250

    Super Mini Mad

  • Members
  • PipPipPipPipPipPip
  • 580 posts
  • Location: Berkshire
  • Local Club: 16V mini club

Posted 18 October 2019 - 10:21 AM

So thats good.  Make sure it's timed correctly.

 

Does it start OK from cold ...just thinking of a way to isolate a coil problem, it it was iffy it might struggle to start?

 

Did you do a compression check when you put the head gasket on ...dont think it's that but it worth a check if you have a gauge?

 

Also, did you redo the tappet gaps when you put the head back on ...once again worth a 5 min check.



#11 Loco69

Loco69

    Learner Driver

  • Noobies
  • PipPip
  • 21 posts
  • Location: Aylesbury

Posted 18 October 2019 - 11:07 AM

To be honest this morning it did struggle starting but I’m going to check the valve clearances again and put a strobe on the timing... what do you set your clearances at?

#12 DomCr250

DomCr250

    Super Mini Mad

  • Members
  • PipPipPipPipPipPip
  • 580 posts
  • Location: Berkshire
  • Local Club: 16V mini club

Posted 18 October 2019 - 11:18 AM

12 thou for inlets & exhaust if its a 998.



#13 ACDodd

ACDodd

    Up Into Fourth

  • Mini Docs
  • PipPipPipPipPipPipPipPipPip
  • 2,200 posts

Posted 18 October 2019 - 11:59 AM

Poor valve seal is also a major contributor to high idle HC readings.

Ac

#14 unburntfuelinthemorning

unburntfuelinthemorning

    One Carb Or Two?

  • TMF+ Member
  • PipPipPipPipPipPipPip
  • 1,224 posts
  • Location: Bedfordshire

Posted 18 October 2019 - 12:09 PM

Strange how the HC reading jumped from 500 to 6000 just from a little drive and a carb tweak.  Was anything else touched at the same time?



#15 Loco69

Loco69

    Learner Driver

  • Noobies
  • PipPip
  • 21 posts
  • Location: Aylesbury

Posted 18 October 2019 - 03:33 PM

Nothing else was touched, however I’ve now reset the tappets and then gone to check the timing by attaching the strobe to the solonoid like usual and the earth to one of the head bolts and nothing happens it’s the same with my mates strobe too, could this be part of the problem




1 user(s) are reading this topic

0 members, 1 guests, 0 anonymous users

Mini Spares