What would cause a high HC reading at MOT?

General Chat About Exhaust, Cylinder Heads, Fuel Systems And Intake

Moderator: phpBB2 - Administrators

Post Reply
User avatar
Ian Anderson
Forum Contributor
Forum Contributor
Posts: 2458
Joined: Sun Nov 19, 2006 9:46 pm
Location: Edinburgh

What would cause a high HC reading at MOT?

Post by Ian Anderson »

Mot on GT40 and the exhaust gas analyser was not happy (3.9 Hotwire Efi JE102 cam)

HC was high (Red) for a while (CO was also high - or so the tester said)

Reset Ecu (power off for 30 secs) and then restarted - was in limit.

Held for required seconds at 2000 rpm and no problems
Final test was CO .995 (Max allowed 3.5)
Final test was HC 815 (Max allowed 1200)

But as I'm about to head to Le Mans classic could this be pointing at a problem somewhere? - some sensor going duff?
Rather have it fixed before I go than try and find a and rover dealer in france or come back 400 miles in limp home (thirsty) mode

Any ideas?


All this electric wizardry still baffles me!

Thanks

Ian


Owner of an "On the Road" GT40 Replica by DAX powered by 3.9Hotwre Efi, worked over by DJ Motors. EFi Working but still does some kangaroo at low revs (Damn the speed limits) In to paint shop 18/03/08.
kiwicar
Forum Contributor
Forum Contributor
Posts: 5461
Joined: Sat Nov 18, 2006 5:00 pm
Location: Milton Keynes

Post by kiwicar »

Hi HC and CO readings. . . it is a too rich mixture, I don't have a clue how you fix that on your ECU. Someone will though.
Best regards
Mike
poppet valves rule!
JJMclure
Getting There
Getting There
Posts: 264
Joined: Mon Jul 21, 2008 9:19 am
Location: wotford 'earts

Post by JJMclure »

exhaust sensor (if it has one sorry not familiar) coolant temp sensor or air flow sensor can affect the mixture, hmmm living up to my helpful or confused bit....
don't nibble on the barrel, pull the trigger!
Post Reply

Return to “Exhaust, Cylinder Heads, Fuel And Intake Area”