 | Home > Technical > OBD sensitivity for cylinders, injectors etc.? |
 
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| ZeDefender Member Since: 15 Sep 2011 Location: Munich Posts: 4731   
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Hi all
I was just wondering how sensitive the on-board diagnostics are for the business end of a defender Puma 2.4? e.g. if an injector is on its way out (over-fueling etc.) or cylinder pressure is slightly low etc. will it generate a code and how sensitive is it? Has anyone had codes for injectors? Cheers Matt Tell someone you love them today because life is short. But shout it at them in German because life is also terrifying and confusing... |
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11th Aug 2014 10:46am |
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| Caterham Member Since: 06 Nov 2008 Location: Birmingham Posts: 6265  
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will be very interested to see the answer on this but I suspect 'not very'
I had my turbo replaced and if I recall the MIL only came on once. I'm sure mine engine has run poorly intermittently from day one but pretty much nothing in terms of codes / MILS but look forward to seeing an educated response to your question.  |
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11th Aug 2014 10:59am |
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| ZeDefender Member Since: 15 Sep 2011 Location: Munich Posts: 4731
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I feared as much. Wouldn't it be nice to have a system that warned you when components are beginning to fail instead of when they're already knackered
 Tell someone you love them today because life is short.
But shout it at them in German because life is also terrifying and confusing... |
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11th Aug 2014 9:33pm |
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| Porny Site Sponsor Member Since: 31 Aug 2009 Location: Sutton Coldfield - West Midlands Posts: 792 
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MIL is only there to alert an owner of faults that will have a direct effect on Emission Compliance...
Its part of the Emission Certification requirement. IRB The home of the first modified Keswick Green 90 - and the first 2.4 Puma through both the 200bhp and 550Nm barriers. www.IRBdevelopments.com www.facebook.com/irbdevelopments www.integrated316.com www.facebook.com/integrated316 |
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12th Aug 2014 9:29am |
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| martinfiattech Member Since: 13 Nov 2013 Location: leicester Posts: 422
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Apart from diesel knock, which may already mean the damage is done depending on when you noticed it.
I have in the past scoped the voltage and current draw on petrol and diesel injectors, back in the good old days it was a sure fire winner to a dodgy cylinder. If your diagnostic kit and vehicle ecu are up to it you can carry out cylinder balancing tests, the ecu cuts the power of a given injector and monitors the rpm and looks at any given losses or gains. A good diag kit / soft ware will give injector correction figures. The current and quickest test is the basic leak back test, however you need to do this at idle speed as the ecu will automatically try to balance the engine by tweaking the injectors time base along with advance and retard. Then test again at 3000 rpm as at this point most systems will shut off the balancing aspect, as a little bit here or there at higher engine speeds won`t be that obvious ( or at least that's the operating structure on bosch systems). So at this engine speed a true picture of injector condition can be gained. Compare both readings. I have used this for 3 fiat motor homes and 2 lvd maxus vans all showing correct injector balancing at idle but when at full load they would shudder. Don`t be tempted to disconnected the electric multi plug on the injector while the engine is running as on later injectors they can go wide open and fill your cylinder with fuel leading to hydraulic lock and a big bill. Some test kits allow you to cap off each high pressure fuel pipe to the injector so you can test each cylinder / injector as required. I`ve done this on larger engines when time is tight and vehicle up time is a nessary, the joy of the modern workshop !! Beware you are dealing with up to 2000 bar it can and will blow a hole in you. Do not open a injector pipe on a running engine. Excuse the spelling I`am better with spanners and wires. |
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12th Aug 2014 9:34pm |
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| ZeDefender Member Since: 15 Sep 2011 Location: Munich Posts: 4731
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Many thanks
I'll try and get started on that tomorrow morning (when I'm awake)
Matt Tell someone you love them today because life is short. But shout it at them in German because life is also terrifying and confusing... |
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12th Aug 2014 9:59pm |
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