440 1.8i auto misses and cuts out when warm

[marct]

Please can someone tell me what's causing the following problem with my 440?
My 440 1.8i automatic is fine when cold but when it warms up it misfires and cuts out to the point where it will not restart until the engine is cold again.
It has new plugs and leads and I also changed the coil pack for a used coil pack.
The RAC diagnosed overfueling and random loss of spark across all cylinders and referred me to a local volvo specialist garage. This garage diagnosed a faulty single point fuel injection unit.
I've just changed the fuel injection / carb unit for a used unit and still have the same symptoms.
I tried unplugging the electrics connection to the idle control motor and it just revs higher but still misses.

[billofdurham]

Welcome to Matthew's Volvo Site.

Have you checked for fault codes using the On-Board Diagnostic (OBD) Unit in the engine bay? This is a first step to diagnosing problems.

Bill.

[marct]

Only getting code 111 (no fault found).
The garage disconnected the battery to reset the fault memory and I've driven it around until it gets hot, misses and cuts out to see if it generates an error code and still only getting code 111.

[billofdurham]

Back to basics. The attached has things to check for both conditions.

440 engine hard start.pdf

Bill.

[marct]

Do you know how I can check the ignition / coil circuit other than replacing the coil pack? Thanks

[billofdurham]

It can be done with an ohmmeter or multimeter:

440 ignition coil check.pdf

If you also need the instructions for checking the ignition amplifier, post back.

Bill.

[marct]

Please will you post the instructions for checking the ignition amplifier. Many thanks

[billofdurham]

No problem:

440 ignition amplifier check.pdf

Bill.

[marct]

Many thanks Bill.

The good news is my 440 appears to be well again

Worked through the list and tests and didn't find any faults. Did clean the electrical contacts and add injector cleaner to the fuel and its driving around nicely.

The only thing I've noticed is sometimes the temperature guage does not appear to work, with the needle stuck at the bottom as though the ignition is off, but the cooling fan still worked / turned on and off.

The diagnosis module still says 111 (no fault found).

[billofdurham]

Thank you for the update.

The temp gauge problem could be a bad connection at the sensor or it could be the sensor starting to fail.

You can check the sensor by removing the plug and checking across the two terminals with an ohmmeter.

Water temperature at 0C 5,800 ohms.
At 20C 2,500 ohms.
At 80C 330 ohms.

Bill.