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| 944 Emissions and MOT https://forums.tipec.net/viewtopic.php?f=25&t=12933 |
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| Author: | chris1976 [ Tue May 08, 2012 10:27 am ] |
| Post subject: | 944 Emissions and MOT |
Hi all, Just had my 86 944 tested...failed on a couple of things. Emissions, it seems to fail on this when ever it is tested by non Porsche garages. Anyway last year even Porsche failed it, so I had a new AFM fitted. It passed. Now 1 year later and after only about 400 miles this year it has failed again at the garage down the road. Not to mention that apparently the lights are pointing in the wrong direction, bit suspicious on that one. Any thoughts about why it keeps failing and if there is some other culprit? Thanks guys, Chris |
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| Author: | jmgarage [ Tue May 08, 2012 1:26 pm ] |
| Post subject: | Re: 944 Emissions and MOT |
Can you scan and upload the emissions printout? Interesting to see the HC, CO, CO2 and O2 at idle and fast idle, those figures will tell us everything including with good accuracy what the cause is. |
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| Author: | chris1976 [ Wed May 09, 2012 7:10 am ] |
| Post subject: | Re: 944 Emissions and MOT |
Hi, this is what the garage gave me... Attachment: Emissions.jpeg Thanks C |
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| Author: | jmgarage [ Wed May 09, 2012 10:39 am ] |
| Post subject: | Re: 944 Emissions and MOT |
Being the CO which is too high, I would point the finger of blame (cue dramatic music) at one of the following. [list=]Fuel pressure regulator leaking into its vac hose (take off the vacuum hose and sniff it Fuel pressure regulator providing high fuel pressure (with the vac hose off it should be dead on 2.5 Bar at the test point Air filter clogged Air flow meter mixture adjustment screw in need of adjustment [/list] Do you have access to anyone with a gas analyser to check your work? Also fuel pressure test equipment would be needed to see what is going on with fuel pressure Also make sure your idle contact on the throttle position switch is clicking just as it closes, it could be faulty or maladjusted causing the car to run on a part throttle map. |
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| Author: | jmgarage [ Wed May 09, 2012 10:42 am ] |
| Post subject: | Re: 944 Emissions and MOT |
Oh, one other possible cause. Coolant temp sensor. Your car has two of these, one controls the gauge and the other tells the engine management system how cold the engine is. If the engine management one is caput, then it will run rich because it will constantly think the engine is stone cold, a little like running an old fashioned car running on choke. (if anyone here is old enough to remember those days!) |
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| Author: | chris1976 [ Wed May 09, 2012 3:01 pm ] |
| Post subject: | Re: 944 Emissions and MOT |
Unfortunately those are two things I don't have in my garage...building up a good collection of tools to service the 44 but not there yet  Will see if my local specialist can take a look for me whilst I peer over their shoulders. Thanks for the advice. Chris |
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