Photography by David S. Wallens
Our M3 didn’t sound so good as it coughed and sputtered after some laps at the FIRM. You know that queasy feeling you get when something really bad happens? That was us. Did we break it?
[Can our E46 M3 run with a new Hyundai Elantra N?]
The problem seemed to fix itself–did we just dodge a bullet?–but we were able to grab a code indicating a misfire.
So, what could have caused that misfire?
Our 2004 BMW M3 came with lots of records. We didn’t see anything about coil packs, but the spark plugs now had 52,000 miles on them.
Time to call the folks at BimmerWorld for some BMW parts.
For spark plugs, they recommended NGK Laser Platinum at $11.99 each.
From the BimmerWorld site regarding ignition coils for our S54 engine:
The same coil design has been in use since 2003 with many updates along the way. This is the current OEM coil, made by Delphi, and replaces previous ignition coil part numbers 12130148594, 12130390064, 12131712219, 12137523345, 12137548553, 12137551049, 12137562744, 12137571643, 12137594936, 12137594937, 12137594938, and 12137594596. BMW is constantly releasing updated versions of their ignition coils to eliminate misfires and rough running engine complaints. Note that ignition coil brands should not be mixed together. Either buy a complete set or buy individual coils that are an exact match for your existing type.
So we ordered six Delphi coil packs–part No. 12138616153–at $41.99 each.
What about injectors? Don’t worry, BimmerWorld’s Daniel Curtis said, as the ones used here aren’t very failure prone.
Fresh plugs, fresh coils, fresh dreams in our heart.
And the engine still stumbled.
And again.
And then, after a few minutes, it cleared up–and it’s been clear ever since. (“Ever since” meaning about 125 miles of driving.)
While it was time to replace plugs and coils, we’re all wondering if there was a problem with some old or subpar gas.
Perhaps the bigger take-home message here: We need to drive this one more often.
Some cars are very sensitive to old fuel. Your car with plugs and coils that were in the latter part of their service life and fuel that is not optimal for it and it very well could be the problem. I discovered that one of my cars will toss a misfire code if I run 93 octane. Feed it 87 and it is happy.
I had a big problem with phase separation in some of the fuel I got this summer. It seemed to get screwy just by sitting in a sealed gas can over three weeks or so.
I'm wondering if the humidity over the summer made some condensation build up in the can that just kick started the process quickly or something.
My S54 did this a few times a year(at start-up), turns out it needed a throttle body actuator(?)..Wilsons new right away.
In reply to Brett_Murphy (Agent of Chaos) :
Maybe we had some phase separation? Somewhere in there we fueled up a few times with some fresh Sunoco so I’m driving the car a bit just to flush things now.
In reply to David S. Wallens :
I read this article about it. In my situation, I put the bad gas into my lawn mower, and it ran (poorly) for a bit, then choked out completely. The carb bowl was completely filled with the water/ethanol phase.
I'd love to see phase separation among the gasoline articles you do, especially as many of us have cars with gas in them that sit around, unused, for weeks or more at a time.
In reply to Brett_Murphy (Agent of Chaos) :
Like show a real example of phase separation? Let me talk to Zach about the realities. My fear is that it might vary due to fuel, container and conditions, but let me ask.
By the way, as of this morning, the M3 starts and idles just fine.
Car is running Sunoco 93.
In reply to David S. Wallens :
Maybe talk about what it is, how it happens and how it can bit us in the ass if gasoline sits around for a while.
In reply to Brett_Murphy (Agent of Chaos) :
Everything I have that sits for even a short length of time gets quality fuel. In my case it's 100 octane unleaded (available at the pump). I put it in everything from the mower to the races cars to the dirt bike................I even use it in my portable generator.
Since I started doing this I've had none of the small issues I had before.
We’ve written about fuel aging before, and see if these articles help answer some questions:
What Happens to Gasoline as It Ages?
Antioxidants, Fuel Stabilizers, and You
The right fuel in the fall might help your engine start in the spring
Fuels for storage: Good, better, best
Water Is Great for Your Plants, Not So Much for Your Fuel System
Should you fill up your classic before parking for the winter?
But it sounds like maybe there are still questions about this. (For the record, I try to put Sunoco 93 in everything since, like Zach always says, a Top Tier, high-octane fuel will simply age better.)
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