304 VT 5lt in VR ute

[Mikecaprice]

I have a vt 5lt and 4l60 in my vr ute running on a vs 5lt loom and ecu vs s2 Statesman dash and body loom climate control ect
It's got 2 intermittent issues
Won't idle or will idle high anywhere from 1000 to 2500 rpm and will hunt up and down at idle and while driving at set speed
Had an issue with it shifting hard and late new TPS seems to have fixed that for now have changed the IAC for several known working ones and a new one
Swapped out ignition module and coil for know working ones
Checked cleaned and added extra earth wires
Changed temp map mat sensors multiple times for known working ones tried 2 different vs 5lt ECUs
Cut out and replaced both the IAC and TPS wiring back past the fire wall grommet with
Done inlet manifold gaskets coolant ports where ugly on manifold changed manifold for another vt 5lt manifold drilled and tapped the single wire temp sensor and mat sensor and added port for map sensor
Still running the vt dizz with a 4 pin plug added to vs loom timing is spot on 10 deg
Alternator is putting out a consistent 14.1 to 14.3v
Has plenty of fuel pressure
Get no fault codes to narrow it down
Set up was running absolutely minty on a vt loom and ecu less than 6 months ago
When it's playing ball it drives well and accelerates fine wide open throttle it pulls hard for a 5lt
Had more than my fair share of commodores and 5lts had plenty of issues over the years always simple easy to fix

 

[gtrboyy]

All the earths joined together going to back of head to avoid interference?

tps,iac02 sensor, etc all join to one earth back of head seems to be common link but non genuine sensors out of range are a nuisance now that we cant get correct parts from holden anymore.

Seeing that it's vr body,vs loom with vt driveline you're basically going to have to go everything plug & plug checking no broken or damaged wires/plugs hoping it's fluke fix or something obvious pops up.

Has it had memcal tune?
Should run ok vs memcal but vt engine slightly different comp & roller cam.

Had mafless tune ls1 vy that occasionaly did similar thing with idle & speed...had to stop turn off restart car....wasnt sure if off shelf tune or iac/tps flipping out.

 

[Mikecaprice]

Vs 5lt loom has an earth and the back and at the front of the passenger side head added the braded wire earth from the alternator mount to behind the air box and added a second from there to the ignition module just for good measure wire wheeled all the earth points to bright shiny metal including the battery to body dash loom to HVAC bracket and the abs one inside the drivers side kick panel no abs or abs unit present or air bag module but as far as I am aware in pre vt those systems are separate and don't have anything to do with the engine

The engine loom was a second hand one from the wrecker many moons ago it was fair rough and had gas wiring in it before I put it on the motor I removed all the tape fixed any broken wire temp sensors earth's ect and re wrapped it up neat

Stock vs memcal on both ECUs
Have a vs S3 caprice that has a vt roller motor in it running vs ecu no worries at all honestly runs better than the non roller motor that was in it also where I borrowed the ecu from to test that

My only other thought is the vt 4l60e is wired different or has a different sensor or value that's causing it but I've used vt thur vy 4l60es in a bunch of vr vs v6s with no issues at all bar the vr s1 12 pin torque converter lock up doesn't work and over 100km the engine light comes on