LQ9 Doesn't Start first Time

[Ultimate_Potato_Chip]

Hi there everyone. Very new to the world of LS Swaps and HPTuners. I just swapped an LQ9 (with LQ4 pistons) into an 88' G20 van and I would say that it really hasn't been a smooth process. But I finally seem to have sorted out my ground issues with the TAC module and am finally getting it to run relatively consistently, however, I've got a small issue that I'm hoping is an easy fix.

For some reason, the engine will not start on the first crank attempt, yet it will fire immediately on the 2nd attempt and I'm too much of a noob to tell what's going on. Fuel pressure is as a solid 60psi, and the pump primes before cranking, however, the engine will sit there and seemingly freewheel (with the occasional backfire out the tailpipe) until i give it a rest, and then crank it again. The second time I hit the starter? *boom* fires great. I took a log of this happening, but admittedly am a little too dumb with the software to see exactly what's going on - or rather- what I should be seeing? It does this with cold starts, but will also do it if it sits for more than about a minute or two between starts.. IE. Fill up with gas? 2 cranks.

I'm assuming this has the possibility of being some sort of calibration/tune issue, but I don't know what to do. Any advice is appreciated!

Log 7-14 - Trouble Starting.hpl
Current Tune 7-14.hpt

[gametech]

Typically an every other crank condition is a bad cam sensor signal. Log it in your scanner channels and see what that sensor shows.

[gtstorey]

Cam position sensor probably isn't working. So, it is having to guess if it on compression stroke. If it guesses wrong, it won't start. It changes the next start and works.

[Alvin]

There are changes to IAC effective area + throttle vs pedal stuff that should be put back to stock. Basically if you don't fully understand what your changing go back to stock. Else things like this might happen. You can do a damn good job tuning a radical setup with just a handful of proper changes. Less is more in this situation

Other than that on swaps I'll see guys who wire the ignition cylinder where things that should have power in RUN will not have power in START.. In those the car might not hit consistently on first key but if the engine speed is high enough when you let go of the key the car will start.

Cam sensor issues will also cause a 50/50 no start. Most of the time you'll get a small backfire on the non- starts. It's common not to have a code with cam sensor issues which makes it harder for people to diag.

[Ultimate_Potato_Chip]

There are changes to IAC effective area + throttle vs pedal stuff that should be put back to stock. Basically if you don't fully understand what your changing go back to stock. Else things like this might happen. You can do a damn good job tuning a radical setup with just a handful of proper changes. Less is more in this situation.

Thank you for the input! To be honest, I'm not sure I changed anything in this area after I got some initial help from someone on this forum. Can you possibly expand upon this? Because I had been having plenty of issues with the TAC modules and things of that nature, so honestly, it could absolutely be an issue with the settings you mentioned above.

Also, I went to a junkyard earlier today and grabbed a delphi cam position sensor (fingers crossed it's good) to swap in and see if the issue gets rectified.