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Understanding Cranking Tuning - How difficult should it be to start a mild cam build?
Hi All,
All my previous tuning and problem solving has been on a SBC 24x conversion which was working great but for some reliability and less oil leaks decided to move across to an LS1 5.7L.
The motor is stock bottom end, has a VCM710 cam, 232/234@110, 241 higgins ported heads, shaved down 30 thou, and a fabricated intake manifold (ebay ripoff of holley sniper).
Using stock injectors, 58psi fuel system with return line, 102mm TB, and trying to do a MAFless tune.
Cam: https://www.lsxperformanceparts.com....ance-camshaft/
My main question is, should it be so very difficult for this type of build to get started?
From a lot of videos I've looked at most people can put a different cam in and still get the car started after cranking for a bit.
I cranked for about 30 seconds with the engine popping and banging and almost starting but never got it to fire and run on its own.
I'm trying to understand and determine if I should be looking for electrical issues (wiring, grounds, power, sensors etc), or if I should be looking at the tune, or worse, mechanical issues.
Currently the motor has open headers, no o2 sensors installed, and MAF disconnected.
Question 1. With the motor specs I have, should I expect it would start without a significantly different base tune, or would this never start without changes?
Question 2. with the P0101, 102 & 103 disabled, will I be able to start the motor with maf disabled, or would this be half my problem?
Question 3. Should I install the MAF and get it tunes that way first, then look at MAF delete / SD only?
Question 4. Do I need the o2 sensors plugged in to get it started, or will it be ok until the PCM tries to switch to closed loop?
Current base tune attached (modified VY commodore LS1 manual with VATS removed, 4l60e selected, some changes to crank spark (+4degrees)and slight change to primary VE)
and the log of trying to start it.
Edit:
Also noticed the TPS is sitting at 0.11v but there's no way to adjust it like the old TPI ones, will have to drill out the screw holes or adjust via the TB adjustment but that might be a bit much to get to 0.48-0.52v
2nd Edit:
I'm not looking to get the complete tune done on this, just enough to start, idle and drive it easy 5kms to get the proper tune done.