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Interesting. Try scrolling to the P0300 errors and erase one at a time. Also, before you buy coils, have you ohm'ed out your wires? Can't put my fingers on the values, but you can always go to the parts store and ask to ohm a new wire. Much cheaper if this is the problem. Have you pulled one of the plugs on the misfiring cylinder? What does it look like?
Im going to have them check the two wires in question. I was going to go buy the coils/plugs then investigate the plugs.
I think the only option is to erase them all.
I wonder if I have to go to the dealer to erase the codes? I called the shop the MB Indy which is giving me the estimate today and they said they only do collision, no scans.
Last edited by mercedesbenzs55; Mar 29, 2016 at 12:04 PM.
Does it misfire only at idle RPMs or at all RPMs? If only at idle, it is most likely a vacuum leak and changing the coils/plugs wont fix it.
When I track down a misfire, I always move the coils to another plug and see if the misfire follows. If not, the coils are fine. I then move the indicated misfiring plugs to another location and see if the misfire follows. If not the plugs are fine too.
A little detective work keeps parts cost and frustration low.
Did the 7 series circa 2002 have air suspension or was it conventional coils? I didn't like the Bangle Butt originally, but the mid-cycle refresh with the redesigned tailights made it look less obvious.
I didn't ask but being a Long wheelbase it must be riding on the air suspension . I like pre Bangle models better
Does it misfire only at idle RPMs or at all RPMs? If only at idle, it is most likely a vacuum leak and changing the coils/plugs wont fix it.
When I track down a misfire, I always move the coils to another plug and see if the misfire follows. If not, the coils are fine. I then move the indicated misfiring plugs to another location and see if the misfire follows. If not the plugs are fine too.
A little detective work keeps parts cost and frustration low.
it does it at about all RPMs. If I keep it vvery steady increases but under 1.5k rpms its ok
your ****ty walmart obd scanner will not clear the codes. It may turn off the CEL, but the codes will still be there. STAR is the only tool that clears all codes. It would also tell you exactly what the issue is.
your ****ty walmart obd scanner will not clear the codes. It may turn off the CEL, but the codes will still be there. STAR is the only tool that clears all codes. It would also tell you exactly what the issue is.
What is this "STAR" of which you speak? I have never heard of such a thing! Is it an acronym, like SCUBA or RADAR or ANUS?
Here are spark plugs from Cylinder #1, #2, #5, #6 in that order.
Coil boots are soft and rubbery with no tears. #1 & #2.
Coil boot #5 and #6, same as above.
The plugs look in good condition. They are NGK R(with Mercedes Symbols) so he had the car serviced. Is it not that the stock plugs are bosch? If so then he had the service done at MB.
Its not fuel because it would be a grayish color due to those cylinders running lean.
Not injectors, not plugs, not coil boots. So it must be coils. Can someone give me guidance please?
Last edited by mercedesbenzs55; Mar 29, 2016 at 01:54 PM.
I didn't ask but being a Long wheelbase it must be riding on the air suspension . I like pre Bangle models better
Yes, I would agree. The E38 is a legend in my book, save for the Nikasil engine cylinder lining problems. I always think of Jason Statham in the first Transporter movie when I see that car. That dude was a bad a$$.
Fuel delivery to these cylinders will continue to be turned off until you clear the codes. This is to prevent raw fuel going into your cat. You need to find a way to clear the codes. Changing parts will not turn fuel back on.
Once cleared run the car and see if the codes come back. If they do, move the coils to another cylinder that does not show a misfire. Then clear the codes again and run the car.
Fuel delivery to these cylinders will continue to be turned off until you clear the codes. This is to prevent raw fuel going into your cat. You need to find a way to clear the codes. Changing parts will not turn fuel back on.
Once cleared run the car and see if the codes come back. If they do, move the coils to another cylinder that does not show a misfire
Hmm. If there was only some way to clear the codes. Try buying more steering wheels.
Once you have a consistent misfire (CEL), the ECU will turn off fuel delivery to that cylinder. This is to prevent pushing raw fuel into your cat. Raw fuel will eventually melt the cat internals.
Once you have a consistent misfire (CEL), the ECU will turn off fuel delivery to that cylinder. This is to prevent pushing raw fuel into your cat. Raw fuel will eventually melt the cat internals.
If the car is running smooth, then he likely doesn't have any current misfires. A misfire in 1 or more cylinders would be very obvious and would normally put the car into limp mode. So the fuel isn't likely cut off. The best way to test for bad coil packs is to do a WOT run. If it runs OK and doesn't send the car into limp mode, then he does not have fuel being cut off. But without a doubt the car needs a full scan as there are likely lots of other active and/or stored fault codes.
He doesn't have $700 to spend on a diagnostic terminal...he's saving up for a tiny refrigerator. People here need to get their priorities straight. Sheesh!
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