Vs 5.0L conversion into VK help

[hsvt472]

Hey everyone. Sorry will be a long one...
Have swapped a vs 5.0L and t5 I to my vk.
Having a few issues which I believe are tune/ecu related.
After first start, 3 min 15 sec, engine will start to die and struggle and will occasionally stall. (3.15 min everytime).
If it doesn't stall it will idle real low and struggle for around 10 seconds and then like some one flicks a switch it will spring back to life and will be fine.
Drives around fine but hates being under vacuum for too long. Coasting down a hill with no throttle input, as soon as you start accelerating it coughs and is very sluggish till you get to approx 20% throttle and clears itself and will run fine. Also pops like crazy on decel.
Thinking maybe vss issue but have the crs adapter for vss and speedo cable. Vss is wired straight to ecu

Any thoughts guys would be appreciated

[Dylan]

Is the engine standard?

The timing of the stalling would align with the ECU going to closed loop idle.

[hsvt472]

Yes standard engine, just a ebay standard tune with no vats

[Dylan]

Ensure base idle and base timing are set correct.
Then we can look at the speed sender possiblity after that.

[hsvt472]

Checked base idle and timing and they're OK. If I'm coasting down a hill it's almost like it's over fuelling. Popping like crazy out the exhaust and intake. Then when you get back on the throttle it runs really ruff until you give it approx 50% throttle then will be fine again

[Dylan]

Is the speed sender hooked up?

[antus]

It sounds like it could be fuel problems, and to do with the end of cold start enrichment. Im not exactly sure when the cold start enrichment ends, it could be that late. If you are suspecting fuel for other reasons I'd consider fuel pressure - regulator, pump (probably not, but could be intermittently failing) and injectors for proper function. When you say ebay stock, do you know its stock or might it have been messed with?

[hsvt472]

Is the speed sender hooked up?

Yeah it has the rod shop right angle adapter and inline speed sensor so I can have cable speedo and vss for ecu. Sensor wired straight to ecu. No fault codes

[hsvt472]

It sounds like it could be fuel problems, and to do with the end of cold start enrichment. Im not exactly sure when the cold start enrichment ends, it could be that late. If you are suspecting fuel for other reasons I'd consider fuel pressure - regulator, pump (probably not, but could be intermittently failing) and injectors for proper function. When you say ebay stock, do you know its stock or might it have been messed with?

Fuel reg is new, checked fuel pressure and it's consistent and doesn't change when it starts to play up.

Can't remember who the seller was now to be honest. Was just a vats removed memcal

[antus]

Consistent is good, but is it right? If its 10% out your fueling will be 10% out. Can you get any data out of the car? If fueling is way out you should be able to see it in the data logs. Are there any errors codes?