As title went for an mot in the mk1 k jet Today the emissions test came back Co 0.043 limit 3.500 Hc 56ppm limit 1200ppm Couldnt get it into the usual place have have my mot.(my regular tester only does a visual normally) These figures are very low should I go richer.
Is the car running OK? not cutting out, good idle, easy to start etc. if so I would leave well enough alone.
Idles perfect 850-900.cold start 1200rpm No issues 39 year old k jet system. Only asking as I've heard lean burn car can run a car hotter. I did ful engine rebuild around 3 years ago. Only set up the engine by sound and smell lol. Engine does pink a little under load more so if too slow in wrong gear. Higher revs longer between gear changes dosnt do it. Car never cuts out but runs (I think )a bit hot.
^^^ agree. Shouldn't be pinking under under load. This is a sign of a lean mixture which is definitely not good.
Yes lean for sure.got an Allen key long one Took me quite some time to get it right idling etc.half a turn should do it but I think I've been here before when I do this the idle speed will race.dont think theres much more adjustment at back of throttle body neither so I think the only way of slowing it is on the timing.its prob just a tweak of all three.i will start with mixture and throttle body.timing as a last attempt to slow it.
Richen around 1/2 a turn.then try to slow engine back down on air screw.if I cant maybe a little adjustment of timing. Not gonna take it to any garages just dont trust anyone with my k jet tbh.id rather just make adjustments but may get a garage to probe for figures after.no garage has touched this car in my ownership.lol Might see if I can get a half decent emissions tester any advice on what actually works for basic readings.
I'd buy a wideband and tune it from there (you can work out CO from reported petrol AFR or Lambda). For sake of £200 it takes all the guess work out, I have one in the Golf and the GTO.
Still got my gunsons colourtune sparkplug in the garage, done many an SU set up with that, stupidly basic but works well.
Not seen one of these plugs but heard about them.you just see through to see the burn colour is that right.what colour do you aim to get?
Admittedly it's more for carb based vehicles but it's when it turns yellow to blue from memory, light blue is too lean, yellow orange is rich. SU carb has a nut to adjust the choke jet length so this is ideal. Had the thing for balancing twin carbs too used that a few times, but always got on better with a single larger carb on the bmc A series.
Fine for rough setting of Idle, but no good for checking the state of the fuelling under load. Definitely a wideband is the way to go, and you'll have it for future setup.
