2.1 DJ engine fast idle

[hughzt]

I’d be grateful for any suggestions as to why my 1986 2.1 DJ engine has started idling at 1600-1800 RPM. The engine was replaced 5 years ago, has less than 5000 miles on it and runs perfectly otherwise.

I’ve checked the following common problems:
1. Idle control valve - it vibrates OK and I’ve even tested a new replacement with no effect,
2. Throttle valve switch - tested and operates as it should,
3. Throttle body/throttle - cleaned and inspected and looks perfect,
4. Fitted new seal between throttle body and inlet manifold,
5. Basic throttle valve adjuster is on the end stop (minimum),
6. The idle stabilisation unit has been bypassed for as long as I've owned the van with no previous problems.

Is there something else that I should check?
The inlet manifold and hoses are the originals, could there be a leak around them?
I’m assuming the gaskets between the engine and inlet manifold are OK as they’re not that old.
Could there be a problem with the main control unit?

[davidoft1]

Check the timing , check it’s consistent and check the Max advance amount

[ajsimmo]

Check temp 2 sender (the blue one in thermostat housing facing LHS of vehicle) and the wiring to it.

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