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Just checked all 8 of my pigtails and they remain dry. I suppose there are some other connectors which occasionally pass oil into the harness too, right? I can't think of them right now...
oil pressure solenoid is also prone to leak into harness.
oil pressure solenoid is also prone to leak into harness.
Good call. I did remember hearing about that once. Mine is disconnected, but I do need to upgrade the protection for the plug ends with a dummy pigtail.
I've driven a couple hundred miles since I cleared the code and it hasn't returned...
Good call. I did remember hearing about that once. Mine is disconnected, but I do need to upgrade the protection for the plug ends with a dummy pigtail.
I've driven a couple hundred miles since I cleared the code and it hasn't returned...
The pigtail for protecting the oil solenoid connection? It's generic but I haven't installed it yet. Currently it's still sealed up with a bunch of electrical tape.
The pigtail for protecting the oil solenoid connection? It's generic but I haven't installed it yet. Currently it's still sealed up with a bunch of electrical tape.
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
Originally Posted by CaliBenzDriver
The tiny single iridium pin does not fire as well as more stubby dual platinums.
Not sure I agree. In highschool physics, we learned that lightning rods were pointed at the top to somehow draw the lightning to them versus the broader rooftop. I think the smaller electrode actually focuses the spark more powerfully as it arcs to the groundstrap.
Not sure I agree. In highschool physics, we learned that lightning rods were pointed at the top to somehow draw the lightning to them versus the broader rooftop. I think the smaller electrode actually focuses the spark more powerfully as it arcs to the groundstrap.
If you put a potential on a spherical conductor, the strength of the electric field will be equal at all points on the sphere. But if you have some other shape to the conductor, the field strength will be strongest in the places with the curvature of smallest radius. So if you have an area on the conductor which is a "point", the curvature will have a very, very tiny radius and the field here will be much, much stronger than everywhere else on that conductor. So that is likely to be where breakdown and arcing initiates. But you are focusing the arcing on a smaller area, so it will erode faster than an electrode with a larger radius of curvature. We have tiny points on our electrodes because they make the electrodes out of expensive super metals like platinum and iridium.
Going back to plane things... The O-300 engine was designed with 1940s technology and I guess they hadn't figured this stuff out yet (at least economically), because they still use "massive electrodes" which are huge so that they don't wear down instantly even though they aren't made of fancy materials:
Not sure I agree. In highschool physics, we learned that lightning rods were pointed at the top to somehow draw the lightning to them versus the broader rooftop. I think the smaller electrode actually focuses the spark more powerfully as it arcs to the groundstrap.
You're 100% right, I was in the class that day! A needle is supposed to draw spark better...
EXCEPT the cylinder gas mixture is not homogeneous. It does not apply well.
A stubby platinum has more opportunities to find a path to ionize a plasma strike than a pin head needle.
I had two Acura 3.2L V6 Type-S with high compression ratio.
A CL had platinum and TL had iridium: fish-bites champions with brang new stock iridium.... switched to platinum: all good then!
Thing is GDI needs exact spark timing so iridium single strike path is mandatory else I'd gladly switch back to dual-platinum.
It's also why I gaped down my plugs a hair at 50k.Mi to help gain reliable spark timingnoff offset aging.
Last edited by CaliBenzDriver; Apr 21, 2025 at 10:04 PM.
You're 100% right, I was in the class that day! A needle is supposed to draw spark better...
EXCEPT the cylinder gas mixture is not homogeneous. It does not apply well.
A stubby platinum has more opportunities to find a path to ionize a plasma strike than a pin head needle.
I had two Acura 3.2L V6 Type-S with high compression ratio.
A CL had platinum and TL had iridium: fish-bites champions with brang new stock iridium.... switched to platinum: all good then!
Thing is GDI needs exact spark timing so iridium single strike path is mandatory else I'd gladly switch back to dual-platinum.
It's also why I gaped down my plugs a hair at 50k.Mi to help gain reliable spark timingnoff offset aging.
The specs on these plugs is 0.8mm. reliable spark timing is from gap
I have mine 0.65 to 0.70... this way in 30kMi I will still have reliable spark gap, grown to near 0.75mm. Each voltage spike must strikes a spark to GND. If not ECU records a penalty with CKP and Lambda feedback.
Wild Acura 3.2-TL is gapped 1.1mm on iridium non GDI. I had those at 0.8mm
Last edited by CaliBenzDriver; Apr 21, 2025 at 10:04 PM.
I'll have to double check the plugs I pulled out, but I have the M278 bi-turbo engine. I believe the OEM plugs I pulled out were Bosch.
D
Indeed the plugs I pulled out were Bosch and were the same part number as the ones I installed.
Last weekend I went out to get some breakfast to heat up the engine before doing the other 4 plugs. When I was almost there, some guy cut me off and I had to do an evasive maneuver that involved full throttle acceleration. A moment later I was pulling into the parking spot at the breakfast place and felt a bit of a misfire and a flashing check engine light came on. I turned off the car, pulled out my scanner, and found a misfire on cylinder 6.
I reset the code, went to eat breakfast, and started the car back up to drive home. No more misfires and no CEL. When I got home, I plopped a new coil on cylinder 6 and replaced the other 4 plugs. Since then I have done a few full throttle pulls with no misfires or codes.
So, who makes the MB branded plugs, Bosch or NGK or someone else?
I've read that quality plugs are good for 100k miles? Sounds like a stretch to me. I plan to replace mine at 50k miles. Good plan?
Last edited by rmorin49; Jul 22, 2025 at 04:37 PM.
So, who makes the MB branded plugs, Bosch or NGK or someone else?
I've read that quality plugs are good for 100k miles? Sounds like a stretch to me. I plan to replace mine at 50k miles.
Good plan?
As Pierre noted: MB spark-plugs are engine type dependant.
Search using VIN-ID for most accurate match.
While you have the intake plenum removed, you'll have great access...
> Replace your Bosch spark plugs + boots (+ air filter)
> Replace the leaky Cam sensors plus disposable pigtails.
> Serpentine kit : belt + wobbly idlers + tensioner is a good peace of mind to preserve accessories.
No surprise down easy road.
Last edited by CaliBenzDriver; Jul 22, 2025 at 05:39 PM.
In my pre-facelifts, gas car had Bosch as OE, flex fuel had NGK as OE, I replaced them that way also
Interesting, I asked my dealer and he said he had no clue. Cost more at the dealer. I've had good luck buying from FCPEuro. Will probably go with what they recommend. I plan to mark the plugs to verify the indexing.
Interesting, I asked my dealer and he said he had no clue. Cost more at the dealer. I've had good luck buying from FCPEuro. Will probably go with what they recommend. I plan to mark the plugs to verify the indexing.
this will be an interesting exercise:
Compare the threads of all replacement plugs vs. originals. How does the GND strap compare?
[nearly identical]
It's both the engine AND plug machining that's indexed to match.
There's nothing necessary do get plugs indexed within range.
Interesting, I asked my dealer and he said he had no clue. Cost more at the dealer. I've had good luck buying from FCPEuro. Will probably go with what they recommend. I plan to mark the plugs to verify the indexing.
If you have a gas only car, its very likely Bosch made your OE plugs, if you have option #929 flex fuel, it's likely NGK made your OE plugs, and if so your coil packs are different also
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
Slideshow: A one-of-one U.S.-spec Mercedes-Benz SLR McLaren Roadster became even rarer after a factory-backed transformation at McLaren's headquarters.
