Discovery V8i - high idle - part 3

Setting Base Idle to 550rpm with bypass pipe clamped. It seems to idle beautifully and then as soon as I let go of the clamp off it shoots sky high and then backs off down to 1100rpm again.

Checked coolant temp resistance and this is fine both hot and cold. One thing I have figured out is that the plenum and most probably the intake manifold is off the original engine, therefore, it is just the block, cylinder heads and ancilleries from the replacement engine.

Would I be able to set Base Idle if I had a vacuum leak? The screw is pretty much all the way in - about 1 turn from bottom. Could that in itself mean there is still a leak and virtually closing the base idle off is merely compensating for that leak?

Category:

Autos & Vehicles

Tags:

• Discovery
• V8i
• V8
• Land
• Rover
• Landrover
• idle
• problem
• high
• 3.9
• stepper
• motor
• plenum

[gingeryoof]

Problem resolved - please see part 1 video