Help with LS2 Swap -- Runs for only a few moments

I've been looking through the forums and can't seem to find the answer. Sorry if this has been answered.

I have an LS2 ('05 Pontiac GTO) in a 1977 Datsun 280z that I can't get to run for more than a few moments. Here are the details:

• I'm a newbie, at HP Tuner and engine swaps, so I won't pretend to know much of anything. Be kind. :)
• The motor was completely rebuilt, no internal modifications (bottom end done at a machine shop, top end assembled by me)
• Long-tube headers, O2 sensors, no cats
• LS3 style MAF (card style) and LS3 injectors
• Wiring Specialties harness + initial flash to remove VATS (I bought HP Tuner afterwards trying to solve this issue)

• The motor will start and run for a few moments. It starts at normal revs (~1,000) but then drops down and stalls after 5-10 seconds. Occasionally it won't start and will back fire. After a few additional cranks, it will start but stall.
• When we first cranked we just had headers, no O2 sensors, and the motor would run but the revs were always very low. I'm not sure if this has anything to do with installing the exhaust & O2 sensors.
• I get DTCs for crank and camshaft sensors
• I tried to run crank relearn but it says all DTCs must be cleared, even after I clear the DTCs and readiness codes say complete (MIL stays on)
• I'm also not sure how I can get crank relearn to run if the motor can't idle and heat up (and I don't have any brake sensors so I'm hoping the relearn will run without this brake signal)

Anyone have any recommendations? Current tune is attached (base tune from Wiring Specialties with DTC codes turned off for O2, EVAP, EGR).

Attachment 103777

Thanks,
Charles

Someone disable the MAP and MAF codes too, those need to be turned back on. Codes P0068 and P0101-103 all need to be set back to factory settings.

What are the codes you are getting while running?

Are you running 58psi of fuel pressure?

Thanks. Here are the codes that come up.

0x7E8: P0016 - Crankshaft Position - Camshaft Position Correlation - Bank 1 Sensor A (Pending, Current, Old)
0x7E8: P0335 - Crankshaft Position Sensor A Circuit (SES, Pending, Current, Old, History)
0x7E8: P0340 - Camshaft Position Sensor A Circuit (Bank 1 or single sensor) (SES, Pending, Current, Old, History)
0x7E8: P0341 - Camshaft Position Sensor A Circuit Range/Performance (Bank 1 or single sensor) (Pending, Current, Old)

And here is the start up log I just ran.

Attachment 103784


I don't have a fuel pressure gauge but it has been able to run for 60 seconds or so when we first started it up (turned off the motor as it kept getting close to stalling).

After you do what 5FDP said, the best thing you can do is put the stock maf back in to get it running. Then fool with the card maf and settings tpo get it to work.
Looks like you changed your map sensor ?? Key on engine off shows 84kpa, should be around 100 depending where you are.

I'm in Denver, which should explain the lower MAP pressure.

I don't have the stock MAF as it didn't come with the motor. Is there a way to get it running with MAF settings from another vehicle that uses the card style?

I'll also double-check the fuel pressure tomorrow, just in case that is causing the problem.

I'd say something is wrong with the harness if you are getting cam and crank sensor codes like that.

disconnect your maf sensor and try it again. I too have a similar setup and the computer doesnt recognize the new card style maf. I had it bog down on me on start up as well. Disconnect your maf and the system will automatically run off from air density. Hopefully this helps. I need a tune that will get me the right tables to get started with fine tuning the maf

Any update on this? I?ve been trying to figure out the same thing for my setup. I went card style mag and my system bogs down on me as well. I know our maf tables on the e40 ecu stops at 12200hz help!!!

Sorry, I didn't realize I forgot to close the loop here. My problem was that the machine shop installed the wrong cam timing gear so the cam position sensor wasn't getting a signal.