Originally Posted by megatron-uk

So the TPS should be adjusted to bring the closed voltage up to what? The 0.3v figure? We can try that. I will say that with the ISCV disconnected and a warm, steady idle, the amal doesn't make any noise.

So far, in the last two days, we've done:

- Replaced seized ISCV with a new one.
- Reset CO screw and set to between 0.5 and 1.0% CO whilst hot and idle.
- Adjusted base idle to around 800-900rpm.
- Checked TPS voltage, which was 0.07-0.1v closed, 4.65v wide open.
- Checked fuel pressure; with vacuum blocked set to 3.5bar; it was 3.8bar.
- Found the idle bypass screw was gummed up with silicone, so replaced the o-ring.
- Checked all sensors are connected up to the right connector in the loom.

A couple of points of observation:

- The idle adjustment screw doesn't make very much difference at all (ISCV disconnected, of course); it seems to only affect the idle right at the very extremes of its range. With the engine up to temperature it will idle at 800-900rpm at almost any point of the adjustment range, other than the extreme points, where it either drops off to almost stalling, or increases up to 1200-1400rpm. It also hunts when you get to either of those extremes. This doesn't seem right to me.

- Tried spraying carb cleaner around the intake system to check for leaks; found no evidence of any.

- Without the ISCV it idles nicely when warm, revs willingly and is quite smooth.

- Even with the nice steady warm idle, hooking up the ISCV again immediately starts hunting and revs bouncing up and down again.

Again, the loom is all brand new, as supplied by MSD - so it's not been hacked or chopped in any way. There's a good solid supply to the fuel pump, direct from the battery and activated by the fuel pump output from the MSD loom.

Spark is good from the two ignition amps and coilpack.

Appreciate all the help so far!