Emission to high with no more adjustment. Help needed.

My car failed it re-test test yesterday for high CO emissions.

The first test showed 8.82%
After a bottle of redX, a good fast run up the motorway
and adjusting the mixture screw down.
The re-test showed a reading of 4.93% and it needs to be 4.50% to pass.

The engine is a 8v Digifant fuel injection in a mk1 golf with a K&N cone filter fitted. Vacuum hose from throttle valve housing to air box blanked of.

I have one full turn left on the mixture adjustment screw. If that does not work
what else need replacing or fixing to get the CO level down. Noted that the engine runs with on obvious problems and the CO level should be lower than 1.5%

Anyone got any Ideas.

is the ignition timing ok? how high were the hc's? (unburned fuel)
Bert

Hi

On the last test the CO was 4.93% and the HC was 273ppm.
The engine sounds OK, but timing looks like a good place to check next.

Thanks for the response.

have a read of my digifant tuning guide:
http://www.no-rice.co.uk/community/showthread.php?t=11429

ignition timing isnt something you can guess at, and you must set it using the proper procedure you cant set it at idle with a timing gun.  as for idle + co, you need to do that in a special way also, using a co meter. cant just mess about with the co screw like you can on the older cars

Had the same problem as you with my brother mk2 digifant. Set the ignition timing correctly and reset the co, now runs fine at 1.5%

it may well be worth checking the state of your filter and plugs, cap, leads too. if the plugs are 15 years old and the k&n is filthy as bugger, it certainly won't help.

Thanks for the set up guide, it came in very useful.

Had a go at sort the emissions out at the week end.

Replaced the Temp sender, dip stick funnel, vacuum pipes and the cam cover rubber bung. Everything else has been clean with injection cleaner.

I also checked the timing which seemed OK. I've been out for a run in the car and it is running great. More power in third and forth gear. Just got to re-book it in for a mot and hope this has done the job. Hope to get the garage to fine tune the mixture/CO level.

I'll keep you's up dated.

If it is still close on CO levels I will MOT if without the filter to take that out of the equation.
I will definitely by getting a K&N cleaning kit, unless anybody Knows a cheep way of doing it.

As to the spark plugs they look OK but would like to replace them for good measure.
The engine has got Bosch super W7 DC at the present time with 0.8mm gap.

But the haynes manual spec's Bosch WR 7 LT+ (1.0mm gap) with a Green ignition coil sticker and Bosch WR 7 D+ (0.8mm gap) with a Grey ignition coil sticker. Problem is the coil has no sticker. Note : the engine is a MK2 digifant injection.

Does it burn loads of oil?

I used k-jet spec plugs in mine, as avs only specced single probe plugs for my digi and I prefer the tripples

I have not noticed it burning much oil but it is only a week end car, so does not do a great deal of mile. why do you ask?

Hi have thought about trying the tripple probe plugs, but have read mixed review for use on older engines

Oil…because if its basically a worn engine, it will burn oil, this doesn't burn cleanly and affects the emissions.

Just reread it though - you say its Digifant - did you fit and wire up EVERYTHING as it was in the old car, including the lambda probe? Did the engine run fine in the donor car it came from? How many miles has the engine done? etc

good point what year digi is this? was it from a MK2, PB code? if so it doesnt have a lamda. if its a mk3 engine then it will have, but even without a lambda the co would be around 0.8% assuming everything is ok.

trippe probe plugs on a digi are fine, they dont offer anything over singles in terms of performance though, the extra probes just give em longer life. the reason i buy em though is the single probes can be bashed out of spec easily, where the trippes cant

The engine is a mk2 digifant PB engine (no lambda sensor), do not now about its history, it was in the car when i got it. Oil pressure seem ok and there is on blue smoke at the exhaust. So hoping the jobs I have done, have solve the emissions problem. I'll find out when I take it for an MOT.

Passed

Great the car passed it's MOT yesterday with a CO level of 0.87% vol and HC at 159PPM.

So Thanks for all the help and advice from everyone.

sounds spot on chap

what do you think it was then mate? glad to see the las chipping in for you

Looks like dodgy temp sensor?

Yes it definitly looks like the temp sender was faulty.

But replaceing the dipstick guide tube (which was cracked) and cam cover breather bung (which allow unregulated air to enter the crankcase ventilation system) has made a big difference to the power of the engine and they are very cheap part to replace. This may not have directly affected the CO level but were worth doing. This Tuning Guide can be found in Golf+ Magazine - September 2006 By Steve 'The Brain' Cresswell.

rubjonny said

have a read of my digifant tuning guide:
http://www.no-rice.co.uk/community/showthread.php?t=11429

ignition timing isnt something you can guess at, and you must set it using the proper procedure you cant set it at idle with a timing gun.  as for idle + co, you need to do that in a special way also, using a co meter. cant just mess about with the co screw like you can on the older cars

From “Emission to high with no more adjustment. Help needed.”

Hi Pal could you resend me the link please its broken, I'm trying to get my C0 down as mine also failed at 9.99%