Help! LS3 w/ E38 ECM - P0502 VSS code and RPM rev limit reduced since tune
Trying to get through my first build and the only thing that's hanging me up is something with the tune. Blah! If anyone has ideas or help I'd be so appreciative. This is my first car build project.
Car Info
1968 Camaro
LS3 stroked to 418 cu. in.
E38 ECM (ECM, transmission, and LS3 all out of the same 2013 Camaro SS)
Whipple 2.9L Supercharger
TR6060 (6-speed manual transmission)
Dakota Digital VHX Gauges
Dyno tuned with HP Tuners
Before Tune
Heat cycled and drove the the car quite a few miles after assembly all with no check engine light, no DTC's in ECM, and shifting in and out of reverse gear fine. It ran like a mean beast!
During Tune
I hadn't been able to get my speedometer to work at all so I asked the guy doing my dyno tune about it to to see if he knew of any ECM settings that needed to be changed to enable the signal wire from my ECM to my Dakota Digital gauge box. I remember seeing him change the "Speed Output Type" to "WheelSpd". He changed a couple of other things but I'm not sure what those settings were. He said to get my speedo hooked up and see if it would then program and work from there.
After Tune
Dyno runs went well. Torque and HP started to drop off right at 6,400 rpm so he said he was going to set my rev limit to 6,200 rpm. Sweet! I jumped in the car when he was done tuning and went to back it out of the dyno bay and noticed the transmission was very hard to put into reverse gear (reverse lockout?) -- it has never done this before. It was snowing outside so I was in a hurry to get it in the trailer and then home to my garage. I didn't drive the vehicle at all for a week or so.
Two problems since the tune...
1) Approximately two miles of driving for the first time after tune, the "check engine" light came on. Checking the code I had a P0502 (Vehicle Speed Sensor Circuit Low Input) DTC. I cleared the code and the light came back on a couple of miles later. With the check engine light on and that DTC in the computer, the transmission was still very hard to put in reverse gear. If I cleared that DTC, the transmission would go into reverse gear like normal but if I drove the vehicle, and the check engine light wasn't back on yet, the transmission would also go into reverse gear... not supposed to do that! The second the check engine light came back on the transmission was hard to put in reverse gear again but it also acted like normal by not letting me accidentally put into reverse while driving.
2) My engine revs shut me down right at 5,200-5,300 rpm now. ...even though tuning guy has it set for 6,200 rpm.
I drove the vehicle back down to see if the tuning guy could disable the "WheelSpd" setting and/or change settings back in the ECM so the car would be like it was before the tune with no check engine light or DTC for VSS. ...he can't figure out what he changed to know what needs changed back to pre-tune settings. If there isn't a setting in the computer that's compatible with my Dakota Digital gauges to get speedo working I'm fine with that as I'll just buy and install Dakota Digital's GPS module. Also, he says he can't find any settings that are limiting my rpm's to the new 5,300 rpm limit. He says everything looks like it is still set to rev limit of 6,200 rpm.
Anyone run into something like this before??? I'll find a way to get some beer to anyone that can help. Promise!
Steve
[email protected]
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