Turbo LM7 5.3 swapped into my BMW 850i has several issues. Specs on the car are:
-Gen 3 P59 ECU 5.3
-Pro Built Automatics 750hp 4l60e
-Elgin 1839p "Stage 1.5", .575" lift, 220/224 duration, 112 LSA
-Pac 1218s
-Billet 7875
-SEP 1000cc, dual wally 255s
-HPTuners Speed Density OS enhanced
Issues are as follows:
1. Nearly stalls when put in gear and idles insanely low. P/N are perfect, idle is as commanded, revs don't hang, doesn't dip, just about perfect on free revs. Put it in any gear and it barely stays alive, and has even stalled before. Revs dip to
about 300 before it shoots back up to commanded, then back and forth. This issue only started after putting the new cam in/new turbo on. Idle values have been tuned for the cam.
2. Timing is WAY too high. Used to hold ~14* of timing at 12psi on 91 octane, now it's sitting at ~24* at 12psi. This issue has only come up with the new cam/turbo. I didn't touch the spark table at all since putting the new parts on (other
than idle values), so I'm worried that this is a different issue in my configuration like calculated airmass being way off.
3. Slow spool. Other people's experience tell me that the 7875 should light off near instantly with this cam/turbo combo on a 5.3, but it takes mine until 6,000rpm to hit full boost in second gear (4,000 pound car, built 4l60e with stock ratios,
Circle D billet 11" converter, 3.64 rear end, 25" tire). Car has been thoroughly checked for boost and exhaust leaks, both are sealed up tight. The fire ring is in the wastegate.
4. Car is slow. Way slower than it should be with the setup it has. Stock cam trucks with a GT45 @ 7psi are faster than this thing is. AFR sits right around 11.2:1 at WOT, both before and after the new cam/turbo. The car doesn't feel
any faster with the new parts, maybe even a bit slower. Won't even break 550 treadwear 235 tires loose in second gear with an open diff; this car should be nearly unusable with those tires on it.
I've attached the configuration file, as well as a log file with some free-revving, some low-speed driving, and a WOT run.
Any and all advice is appreciated as I can't find anyone who's willing to remote tune it since it's a swapped BMW.
Figured it out, answering here and leaving this thread up for future google searches:
My intake temp sensor died at some point during all the work and the ECU defaulted to -40*c. Set it to default to 100*f with no sensor connected and all of these issues were solved.
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