[2e9x's]

Here's the scenario...I'm driving along this morning. The car is a June 07 production 335i 6MT with about 6,500 miles. Ambient temperature is 55 degrees. Terrain is flat. I am doing about 2500 RPM in 2nd gear, oil temp at about 225 degrees. I had been driving for about 20 minutes since my last stop. I accelerate using about 1/2 throttle to change lanes.

I immediately hear radical detonation, the car bucks and shudders, so I instantly get out of the throttle. Car resumes normal operation. The rest of my drive to work (about 20 miles) the car behaves perfectly. No warning lights, no limp mode, nothing...I get on it a few times trying to replicate the problem and it behaves 100% normally.

Odd detonation...not WOT, not high boost, not high load...cool ambient temps, low operating temperature. Just odd...

Think my HPFP is dying?

Add this to the analysis. The other day I was driving home from work when I got a message that the SOS system was unavailable. That was untrue...I tried it and it worked ok. The next morning the warning was gone.

I had recently filled-up with 91 (the best we CA folks can get) from Shell. Perhaps bad gas? That could be, but then why would the car be running perfectly the rest of the day?

The crank times are normal as far as I can tell. I wonder if I have some other electrical gremlin? It's weird that the car is acting-up all of a sudden.

Thanks guys! As always your constructive input and expertise is appreciated.

[roy@gambitmotorsport]

How much gas was in your tank? Do you have any exhaust mods?

I've figured SOS coverage depends on cell phone range, but never gotten a warning in places I know I'm out of range - I'd bring that one up with the dealer.

[2e9x's]

Originally Posted by roy@gambitmotorsport

How much gas was in your tank? Do you have any exhaust mods?

I've figured SOS coverage depends on cell phone range, but never gotten a warning in places I know I'm out of range - I'd bring that one up with the dealer.

Thanks for responding Roy...

I had > 3/4 of a tank. No exhaust modifications.

I only mentioned the SOS because the 2 electrical faults occurred close in time to each other. Most likely they are unrelated...but who knows?

[RiXst3r]

When my HPFP died, I did not have long cranks.. I did have the random non repeatable stutter that would happened every once in a while, and then about a week later, the car wouldnt start without stuttering and then stalling out....

[2e9x's]

Originally Posted by RiXst3r

When my HPFP died, I did not have long cranks.. I did have the random non repeatable stutter that would happened every once in a while, and then about a week later, the car wouldnt start without stuttering and then stalling out....

hhhmmm...the other day the car started, stalled, and then started correctly. Perhaps it is a good thing I already have an appointment to take the car in. Hopefully the pump will last until Tuesday.

[2e9x's]

The car is at the dealership right now. What I learned yesterday should make you all just a little more cautious about installing any piggyback in your cars...

The ecu stores far more information about fault codes than I would have believed. In the scenario I described earlier, the car knocked and stuttered really badly. However, it did NOT throw a CEL!

Well the tech was able to tell me the date, mileage, RPM, and all running conditions at the time of that incident because the ecu stored a fault code DESPITE the lack of CEL or limp home

Apparently my car had a fault F030 (I think) "ignition cylinder 4 not allow" The tech is tracking it down and trying to determine why that happened. My car (100% stock) is running very lean on the rear bank of cylinders for some odd reason. If he fixes that, I guess my MPG will go all to hell... (j/k)

Also note that fault data is transmitted to BMW for diagnosis and repair. One member already had warranty problems because he left physical proof behind of his piggyback. Just beware that there may remain an electronic trail whether you know it or not.

Be careful guys!