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I have a 2007 BMW 335xi.
75.5k miles.I’m trying to solve a misfire problem.
The misfire has no pattern. Every time it shoots an SES light, the cylinder(s) shown up on the scan tool differ.
It only “sputters” and misfires when it is above 160 degrees…meaning, the turbos put out more boost than when below 160 degrees.
…which makes me think something in the ignition system is failing due to high boost.
When it is below 160 degrees (not operating temp), the car runs like a monster (in a good way).
If you get too heavy on the throttle, the car will “sputter”.
If you floor it, the car immediately shoots an SES light and goes into limp mode. The engine runs out of time and the car idles very rough and has NO power. Once you restart the car, it runs like normal again unless you try to floor it.
If you ease into the throttle, you can go all the way up to 120mph without a misfire.Either the HPFP can’t keep up…the coils aren’t firing, or the injectors or messed up.
How would you even diagnose this?
I don’t want to throw money at it and hope it works…I want to correctly find the problem. However, I don’t see how you could ohm check (or diagnose in general) a component that ONLY fails under high boost conditions.
The plugs were changed 5k miles ago, so…I don’t think it’s them…UNLESS NGK Platinums don’t fit the vehicle’s ignition system.
The coking on my intake valves were cleaned 300 miles ago.
So, that (possibly) eliminates 2 factors.To give you a better understanding of what I mean when I say the misfire has no pattern…I went out and did a series of runs and recorded the codes that popped out.
The ONLY module that had codes in it was the engine module.
No fuel pump codes. No tranny codes. No nothing.Codes.
29CF — Cyl 3 Misfire.
29CE — Cyl 2 misfire.
29D0 — Cyl 4.
29CC — Misfire In Several Cylinders.
29CD — Cyl 1.
29D2 — Cyl 6.
29D9 — Misfirings in case of tank filling level too low..So, I cleared those, and then I went out and punched it a couple more times.
Here are the codes.29CD — Cyl 1.
29CF — Cyl 3.
29CE — Cyl 2.
29CC — Several cylinders misfiring.
Cleared.29CF — Cyl 3.
29D2 — Cyl6.
29CC — Several Cylinders.
Cleared.29D2 — Cyl 6.
Cleared.Floored it from 0-100mph. No misfire. Pulled over, floored it:
29CF — Cyl 3.
29D2 — Cyl 6.
29D0 — Cyl 4.
Cleared.29CD — Cyl 1.
29CF — Cyl 3.
29CC — Several cylinders.
Cleared.I used a Bavarian Tech tool to scan the car.
Thank you.
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Replies
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seems like random misfires.start with a power balance test.
do it both ways.fuel and spark. also the NGK plugs are wrong
for that car. The correct plugs are Bosch. Try putting the correct
plugs in first to see if the problem is resolved.Check your owners
manual for the correct plugs.A “power balance” test?
Also…I guess me putting plugs in it doesn’t do much good if they’re the wrong ones.
But would they make THAT big of a difference?
Also, if they are the wrong plugs…wouldn’t the problem be static? It’s getting worse and worse as we speak. I can hardly press the throttle down when it’s at operating temp or it’ll miss. It’s starting to do it even after 3min of driving the car from a cold start.
So, I don’t know.The problem was also occurring when I had the other plugs in (hence why I changed them).
However…those plugs were the OEM plugs and had 70k miles on them…goto the tail pipe can you hear a put-put like sound? changing plugs on some cars is the one of the few things i can do myself to a car. and exprience tells me that misfiring or vibration is due to plugs not much else. Plugs are plugs and my expierence with not just cars but electronics is if it fits it works. Did you look up the car in the book where you got the plugs? its possible the gap isnt correct i dont think brand makes a shitbit of difference.
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