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Feb 14, 2007 14:23:35 GMT
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The Benz went in for an MOT on Monday and failed on a few things, one of which is emissions. So I'm setting about trying to get them down. Here are the results: CO: 7.02% vol HC: 1695 ppm CO2: 6.63% vol O2: 5.39% vol Lambda: 0.95
So it's the top two that have failed. By my reckoning I have to get the CO level down to 4.5% and the hydrocarbons down to 1200ppm. So I'm just a shade over... ;D
It's not been run for a long while, so a damn good blast should clear some of the wibblepoo out. I've changed the plugs (sooty as hell), dizzy cap, rotor arm and points. The oil is clean and fresh... anything else I can do? Or should I just drop it in to the local garage for a bit of tweaking, seeing as they have the machines and that?
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Feb 14, 2007 14:29:57 GMT
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Does it have a carb? if so , set it up. Its running too rich which is why your plugs were sotted up.
You could also try thrashing the curse word out of it.
Paul
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Feb 14, 2007 14:32:28 GMT
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Changed the air filter lately ? Taking it out might just be enough Run the engine breather seperate to atmosphere What fuel system is it running ?? has it got the bosch fuel metering head ? If so it is just a tweak with a 3mm allen key from memory to fine tune the mixture
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Feb 14, 2007 14:32:58 GMT
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ITALIAN TUNE-UP FTW.
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Seth
South East
MorrisOxford TriumphMirald HillmanMinx BorgwardIsabellaCombi
Posts: 15,537
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Feb 14, 2007 14:40:24 GMT
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Hmm, does sound like its running rich. Presumably theres some automatic cold start enrichment device? Ought to make sure that's working properly. If its not getting used much and always on the "choke" that wouldn't help and a blast would surely improve things.
*Disclaimer - I've never had to do an emisions test!
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Follow your dreams or you might as well be a vegetable.
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Feb 14, 2007 14:40:47 GMT
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It has a Stromberg 175CDT carb. I'll give that a tweak. The auto choke seems to have stopped working recently but looks as if it's stopped on the "Off" position, but I'll give that a looking over just to be sure. The air filter is a K&N job. I'll give it a bash on the floor and see if it needs cleaning. Or just take it out like you say Dom! The breather is venting to atmosphere as the pipe is broken and I've never gotten round to fixing it! ;D Pog- what's an Italian tune-up?!
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Feb 14, 2007 14:40:48 GMT
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One of the garages I used to take my Alfa to for MOT just adjusted the carbs leaner and leaner until it passed.... it was virtually undrivable afterwards,.. but a quick screw driver fiddle soon saw that fixed
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Feb 14, 2007 14:42:30 GMT
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*Disclaimer - I've never had to do an emisions test! Neither did I until this stupid computerised curse word came in. Cut-off date for a visual check is Aug 1975 and mine was registered Oct 1975.
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bstardchild
Club Retro Rides Member
Posts: 14,936
Club RR Member Number: 71
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Feb 14, 2007 14:44:37 GMT
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The breather is venting to atmosphere as the pipe is broken and I've never gotten round to fixing it! ;D Is the other end where it would go into the manifold or air cleaner blocked up? Pog- what's an Italian tune-up?! Got a ring road near you..................... Go take it for a blast on the way to the next MOT
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Feb 14, 2007 14:51:44 GMT
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I'm dredding my Mini's emisions test. Its a 1994 car but due to a fire the engine is a 1990 carb. But because I've got a straight thru exhaust they are a little higher than normal. The MOTer always does the car as a 1994 injection engine with cat, despite the fact I've said its a 1990 engine and proved it with the engine number but still no one passes it.
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Feb 14, 2007 14:58:41 GMT
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If its on motrinic take your idle control valve out and clean it with carb cleaner plus as said above drop your tickover with the 3mm allen key wash air filter flush and change the oil and filter and give it a good run out on the day ov the test.
A hot engine runs cleaner than a warm one.
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Jeeves
Part of things
Posts: 25
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Feb 14, 2007 14:59:34 GMT
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Used to work wonders on Transits when I worked in London - airbox off and a sprint up the M1 for 5 miles. Almost fresh air from the exhaust afterwards.....
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Feb 14, 2007 15:00:00 GMT
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Italian Tune up involves driving it like you stole it!
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1986 Citroen 2CV Dolly Other things. Check out my Blog for the latest! www.hubnut.org
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Feb 14, 2007 15:10:09 GMT
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The breather is venting to atmosphere as the pipe is broken and I've never gotten round to fixing it! ;D Is the other end where it would go into the manifold or air cleaner blocked up? No, the pipe is disconnected between the rocker cover and the PCV valve. I have a pipe going form the other side of the PCV to the inlet piping. I think I might try an Italian tune-up too in that case! Can't do any harm ;D
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Feb 14, 2007 16:25:58 GMT
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:)I doubt a good thrashing will bring the emmisions down from as much as 7.02%. You'll need to get the fuel mixture weakened, which will save you money on fuel and make the engine run better. A mixture as rich as that can start to cause bore washing problems.
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Feb 14, 2007 16:29:26 GMT
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I'm dredding my Mini's emisions test. Its a 1994 car but due to a fire the engine is a 1990 carb. But because I've got a straight thru exhaust they are a little higher than normal. The MOTer always does the car as a 1994 injection engine with cat, despite the fact I've said its a 1990 engine and proved it with the engine number but still no one passes it. :)appeal to VOSA...the tester should test it to the age of the engine that are proving it to be.
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Feb 14, 2007 18:17:46 GMT
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:)I doubt a good thrashing will bring the emmisions down from as much as 7.02%. You'll need to get the fuel mixture weakened, which will save you money on fuel and make the engine run better. A mixture as rich as that can start to cause bore washing problems. Good point. I think I'm gonna have the auto choke assembly apart tomorrow. It may be stuck slightly open. After that, a tweak with the mixture, top up the dash pot with ATF... that sorta thing...
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Feb 15, 2007 15:51:50 GMT
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An update for anyone interested...
Well, I've had the auto choke assembly apart. It's been nicknamed "The heart of darkness" by MB owners across the pond due to it causing all kinds of grief. With this in mind, I didn't delve too deep into it - just a rudimentary clean-up and check whether the bi-metallic spring was still intact. All seemed OK there.
I got the engine nice and warm and tweaked the mixture. This too seems to be a black art shrouded in secrecy as I could find VERY little info on how to do it. Basically the main jet is raised / lowered by turning the anti-dieseling valve in or out. So I raised the jet as much as I could before it started to stutter, then turned it back slightly and locked it off.
In all honesty it doesn't seem to have done much - the engine ran pretty smoothly before, and it does now. I'll take it for a blast on the weekend, give the plugs the once-over, and pray for no sootyness!
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Feb 15, 2007 18:32:52 GMT
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fit an extra CAT ive got these silly tabletsfrom my gran there going to save me no end of fuel and reduce the emissions greatly.......yea rite ill let you know next week though after the MOT :/
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once again rocking with 1117cc and 4 gears!
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Mike
East Midlands
Posts: 3,387
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Feb 15, 2007 18:37:07 GMT
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One of the garages I used to take my Alfa to for MOT just adjusted the carbs leaner and leaner until it passed.... it was virtually undrivable afterwards,.. but a quick screw driver fiddle soon saw that fixed Thats how i got my old Golf through its MOT!
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