1988 T25 2.1 idle speed?

[xs1100515]

What is the correct idle speed for a 2.1 petrol wet boxer? Its fuel injected with Digifant petrol injection. It's been 'looked at' twice and both times appears to be racing at idle. It starts well, runs well and the high idle does not seem to affect gear changing. So what's the problem you may well ask. I have heard that boxer engines run with a high tickover but what is high? Once it warms up it's about 12 to 1300rpm. I would have thought 8 to 900 would be right. I have a Haynes manual but they aren't what they used to be and doesn't list any figure. Just a reference to manufacturers technical data. That's what I bought the book for.

[hakuna matata]

850 to 900 rpm.

neil .

[California Dreamin]

Digifant 2.1...either MV or SS engine code...880rpm plus or minus 50 rpm.

There are several possibilities:
An air leak somewhere or the inlet manifold side (vacuum pipes/gaskets etc).
A badly setup/maintained idle stabilization valve. (see idle setup notes in the Haynes) Idle by-pass valve etc.
The micro-switch on the throttle stop, not functioning properly (needs to click 'closed circuit' when the butterfly returns to it's rest position).

Martin

[ajsimmo]

Could also be...
Possible high resistance in the blue temp2 sender circuit (either faulty sender or manky wiring). ECU reads this as cold engine and increases fuelling and advances timing..
Idle air screw too far open (lets air bypass throttle butterfly thereby opening AFM a little more, ecu increases fuel).
Someone may have played with the base setting on throttle housing, leaving butterfly slightly too far open?

For full diagnostic routines see Digifant manual HERE

[ermie571]

Well - that's the OP's weekend sorted

Em
xx

[xs1100515]

Thanks everyone

Em - you like your LPG