Quote:
Originally Posted by andrewwynn
How slow are you going when it stumbles?
My very first repair on e53 was from a bad CPS. Symptom: stumble when turning into a parking space.
That said i don't think that would affect fuel mix.
Do you have a scanner that can watch/graph realtime?
O₂ sensor graph will be pretty helpful.
–awr–
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Ok, there have been four stumbles so far, enough to make me not want to test drive, fearing a stumble/stall far from home, in traffic.
- 1) backing out of my driveway (backed up, turned 90 degrees to the right, and drove forward 100 feet, then made a 90 degree turn the left, and drove forward at moderate acceleration, with a short stumble,
- 2) when leaving the gas station onto a 2-lane secondary highway...a 90 degree turn to the right, and rapid acceleration to pull away from rapidly approaching traffic...causing a longer stumble, and near stall,
- 3 & 4) on an uphill left 90-degree curve, it seemed about to stall or go into limp mode for about 10 seconds following the curve, but it regained power just in time to do the same thing, on a flat 90-degree right curve that immediately followed, at about 45-50mph,
- 5) conversely: on four successive turns following that, on two left turns, onto short streets at moderate speed 30+mph, then another two right turns, first into my driveway and after 100 feet, further downhill to my parking area, also probably driving a bit too fast, there was no stumble.
And, there is the incident on the first test drive where the transmissin hung in gear going uphill on the first curve mentioned in "3 & 4", above, but without any stumbles on those curves & turns, during that first test drive.
And, WTF is a rich condition being reported if there is a fuel cut-off happening (obviously there is one, onhard curves and turns). It got worse after I reset adaptations.
I don't remember how I used to record/graph my O2 sensors using Torque Pro, but I did at least once previously, and I've no idea how to do it on my Foxwell. But, watching the realtime display on my dashboard tablet, I can see the O2 sensors working fine.
I ordered Tee-fittings from Amazon so I can use a hand-held vacuum pump (I have two: one in a brake bleeder kit, another in a cooling system test kit) to vary the vacuum to the FPR, to see if the fuel pressure to the engine varies. And, i'll have to wait for the wife (out of town) to drive behind me, in case of stalling away from home (so I can tow it home, just in case the system fails entirely, way out in the sticks). This might take awhile to diagnose, so I'll be missing the inspection deadline, by a lot.
At what point does the "sudden change in performance and going from lean to rich" lead back to the simple, single act of replacing the fuel pump, and touching nothing else? I'm tempted to let the X5 sit, until I save enough to afford an INDY to repair it (flat-tow expense to the other side of the county, who knows what parts they'll throw at it, and exorbitant technician's fees once there). Sorry for that, but this problem just makes no sense to me.
Did the inspection station plugging into my OBD port damage my DME??, and why would even that cause 90 degree turn stumbles??
Oh, I already mentioned that I added a bottle of Cataclean to my fuel two days prior to going for inspection. Possible link to my problem? i'm trying to cover all possibilities, though I doubt that Cataclean could screw up the fuel system ON TURNS, especially since I've been using fuel injector cleaners in increasing amounts, for 4.5 years (any tank or fuel line deposits surely have broken loose long before now).
But, if there were deposits knocked loose by the Cataclean, and were sucked up by the siphon pump (partially clogging it) and/or fuel pump (clogging it enough to burn it out, after 20 years of service), how would I clean the system to go back to a normal state?