Excess Hydrocarbons - last MOT point 260E

[angst]

Car doesn't idle smoothly causing excess hydrocarbons. Runs fine otherwise.

Have new plugs, dist. cap and rotor and leads changed last year.

Have sorted out straighforward MOT failure points like not realizing a tyre had worn (seemed new last year to me!).

Any ideas?

 

[meanie]

What year is the car?
What was the co reading?If it's too low that will cause your fault.
Try to find some of this & see if it helps.It works better than any other injector cleaner that I've come across.
http://www.forteuk.co.uk/Specialist_Injector.htm
Have you noticed any blue smoke,as the 103 engine is susceptable to valve stem seal problems.

 

[star]

ecessive Hc is due to unburnt fuel, check for an air leak, check plugs as prone to carbon fouling if valve seals gone as mentioned, check co2, then check injector spray pattern. do one at a time to see if improvement is noticed.

 

[angst]

The car is 1989.

Haven't noticed any blue smoke - goody that mean the valves are ok?

Plugs have no fouling. CO reading .08%

Have sprayed injector cleaner - Forte is good stuff but can't find list of stockists on web.

Have changed distributor cap which has made a slight difference in running.

Should one feel any engine vibration in a 124 at idle and could these cars have been described as really smooth?

Thanks

 

[meanie]

Is that a typo,or is the co reading really 0.08%?If so,that is way too lean,Richen it up to 1% & that will probably sort out your HC level (lean mixture will lead to high HC).It could indicate an air leak as previously stated.
A nice 103 engine will be very smooth at idle.

 

[C220GJS]

Forte injector cleaner available here; http://www.conceptautosport.co.uk/products.php?plid=m14b56s272p974&rs=gb ; or just Google it.

 

[star]

Is that a typo,or is the co reading really 0.08%?If so,that is way too lean,Richen it up to 1% & that will probably sort out your HC level (lean mixture will lead to high HC).It could indicate an air leak as previously stated.
A nice 103 engine will be very smooth at idle.

+1 def as above

 

[angst]

thanks

Thanks for this Meanie, C220GJS and Star services.

Will try this!

 

[brandwooddixon]

Stuck EGR valve?

 

[bouncer]

Can you post the complete set of failed emissions results
CO
HC
Lambda

For fast idle, second fast idle and natural idle

sTeVe

 

[angst]

Can you post the complete set of failed emissions results
CO
HC
Lambda

For fast idle, second fast idle and natural idle

sTeVe

The only MOT emission results supplied to me are


CO level 0.08% then .09% after new plugs

HC Level 1211ppm then 1759ppm after new plugs

 

[bouncer]

Agree with those above, weak mixture or lean misfire. The misfire will lower the CO, so that's possibly why the CO percentages are so low.
Also, as above check EGR, if the exhaust gas is entering the intake system at idle then this will have the same symptoms you describe + high HC
Check also the Lambda sensor signal voltages. This will give you a good indication on what's happening regards to lean or rich running. or even a lazy or faulty lambda sensor.

sTeVe

 

[angst]

Um?

Well this is a mystery.

The garage rechecked the emissions which now came to

CO 2%

HC 800 ppm

The only difference is that new plugs were fitted after the first reading and new dist. cap before this last reading.

The new cap made a bit of difference, possibly, in running but no real difference in idling.

However I couldn't find any vacuum leak as I'm not much of a mechanic and a friend offered to look at car this weekendn.

What's/where's the EGR by the way?