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#1
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changing spark plug wires
ok, my 2000 ml320 has been running really badly in the past few days. it has apr. 55,000. i took in to euro motors and they said the spark plugs and spark plug wires need to be replace. so i thought no problem until they quoted me for $1400!!!! are you kidding me. i looked online and found all the parts i need for under $250. so now im thinking ill do it myself. im a good home machanic. i have changed the plugs and wires on my bmw and i do all the maint my self (brakes, oil, etc.) i found on this forum driections on how to change the plugs and it seems like a sintch. however i dont know about the wires.i cant really find any info anywhere. if it is like i think it will be, all i do is unplug the old ones and put on the new ones (making sure to match the connections), however im at college right now and the ml320 is at home so i cant really look and see. should i just go ahead and order the wires and plgus? am i right about simply plugging and replacing? wiill i need any special tools?
again i am a good machanic, i even installed a turbo in my saab. im just affaid that with the complexity of this engine i might mess something up and have to pay big. |
#2
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plug wires
what brand are the items you have found? i have had customers who have had problems using non Original ignition parts for these engines. as for needing plug wires i have worked on possibly hundreds of ML's and other mercedes cars with the 112 engine with more mileage than yours and have had to only replace wires individually, never all at once. so i would re asses the situation. the plug wires are sold as individual parts from mercedes, so i would replace the plugs, then see how it runs. you may still have other issues. does the check engine light come on or flash? flashing indicates a missfire in the engine that can damage the catlysts. if the light is on have someone who can pull the codes and see what is there.
Ray mercedessd@cox.net |
#3
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well actaully it was in the shop about a month ago. they replaced 2 wires. this time they say all the wire need to be replace. the wires i found are "Beru" which i believe are original brand.? the plugs are Platinum+4 bosch which iv heard good things about. the check enigne light did turn on however i wasnt driving it when it happend so i dont know if it flashed or not. the funny thing is most of the time it runs fine, just sometime it doesnt.
i was a little scepticle when i heard it was the spark plug wires but the dealers is a big mercedes dealer and they had the tools to check it (i think). i believe thier exact words were "missfiring and plugs are fouling" let me know what you think. |
#4
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wires
i think you could do it yourself the only trick is using a 17mm wrench to remove the wire ends. bremi is what mercedes uses and my source says if you buy 12 of 112-150-01-18 they will be long enough to fit all, i would recommend using the plugs mercedes recommends, the +4 is a good plug, i however have never used it in this application. the mercedes number you need is 003-159-66-03-26 which is the same plug as the Bosch F 8 DPP 332
i have included a picture. let me know your prices i may beable to save you some money. Ray mercedessd@cox.net Last edited by carson356; 02-05-2006 at 02:36 PM. |
#5
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yeah i found that plug, 5.88 at overnightautoparts.com
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#6
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plugs
i foung it for $4.63 ea with $3.85 shipping
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#7
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I pulled my plug wires by hand with a mechanic's glove on. Don't need no wussy wrench.
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#8
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There is no need to change all the leads. You need to work out which ones are faulty. You can try checking their resistance individually when cold (2000ohms +-200ohms). This isn't great way to check them, an osciloscope is the best way but ohms will find totally dead leads.
Misfires on 112/113 engines are hard to find without the osciloscope due to the twin spark plug, they fire approx 12degrees crank rotation apart at low revs and then together at higher revs. Spark plug A fires first for 2 cycles and then it switchs to plug B firings first for 2 cycles. A totally dead plug won't cause enough of a misfire to shut down the cylinder. As for the spark plugs use only genuine or equivelent bosch plugs, it's very expensive to start experimenting on spark plugs when you have to buy 12 plugs. ![]() Trust the guys in the lab coats who designed the engines and not the guy in the overalls in the local auto store to tell you which spark plugs are best for you engine. ![]()
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Alex. MB Tech Sydney, Australia Volvo 122S W201 190D 2.5 manual W202 C240 W203 C32 |
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