1985 240 intemittent no spark ?

I've experinced this problem a couple of a couple of years ago and it
was a bad Hall sensor . However it checks out fine with a meter .
Could someone please help me with the diagnosis of the problem here .
thanks

 

You say it's intermittant, does the hall sensor check out good when the
spark isn't there? I've heard of the vacuum advance intermittantly breaking
the connection.

How's the wiring harness?

 

I have an '86 240 and also experienced intermittent at first and then no
spark - at the sparkplug wires. The rotor has a resistor in it that had
disintegrated (the rotor looked very normal - virtually the same as the
replacement). Check this if you have spark at the coil but not the plug
wires.

 

The last time I caught it not working, there appeared to still be
continuity in the Hall sensor , The wiring harness is not great but
Ok I thing with the only visible deterioration around the gray
firewall connector which was repaired by stripping back and splice in
new wire as necessary . Are there any other connection points ( other
than the ECU plug, Coil terminals , distributor Hall sensor
connections - has Bosch distributor ) to check in troubleshooting
this sort of problem ?

BTW- does this model have a separate ICU ( different from the ECU
located near the windshield washer bottle ) , if so where is it ?

- thanks

 

The last time I caught it not working, there appeared to still be
continuity in the Hall sensor , The wiring harness is not great but
Ok I thing with the only visible deterioration around the gray
firewall connector which was repaired by stripping back and splice in
new wire as necessary . Are there any other connection points ( other
than the ECU plug, Coil terminals , distributor Hall sensor
connections - has Bosch distributor ) to check in troubleshooting
this sort of problem ?

BTW- does this model have a separate ICU ( different from the ECU
located near the windshield washer bottle ) , if so where is it ?

- thanks

 

Update - I still have not isolatign the problem . Howver wiggling the
harness at verios points gets it going. I am pretty sure that it
either a bad connection or a broken wire in the harness but I want to
check at all the typical places for failure before going all the way
replacing/ rebuilding the wiring harnesses ( engine haness ? ,
ingition harness ? ) . Where ? -thanks


My Previous post -

The last time I caught it not working, there appeared to still be
continuity in the Hall sensor , The wiring harness is not great but
Ok I thing with the only visible deterioration around the gray
firewall connector which was repaired by stripping back and splice in
new wire as necessary . Are there any other connection points ( other
than the ECU plug, Coil terminals , distributor Hall sensor
connections - has Bosch distributor ) to check in troubleshooting
this sort of problem ?

BTW- does this model have a separate ICU ( different from the ECU
located near the windshield washer bottle ) , if so where is it ?

- thanks

 

Your 240 uses an ignition system sourced from Chrysler, which has
serious problems with the connector to the ignition computer. In fact
Volvo recommends changing that harness if it is ever disconnected from
the computer for any reason.

--
Mike F.
Thornhill (near Toronto), Ont.

NOTE: new address!!
Replace tt with t (twice!) and remove parentheses to email me directly.
(But I check the newsgroup more often than this email address.)