the car will randomly not power up the ecu after driving and then randomly start working (not for long) after sitting. i can't seem to develop a pattern to chase the issue down. NOTE i have had 7 different main power relays the first 2 were known good used the rest were new all factory bmw and 1 bosch.
using this diagram to check the pin outs on the harness at the ecu (with it disconnected and key on and off as follows:
link to diagram http://www.megasquirt.325ix.com/MS_t..._motronic.html
with the ecu disconnected and the key on it reads as follows:
#2 no ground
#3 ground, but no buzz (indicating a weak ground)
#14 has no pin
#19 ground with key on
#24 ground with key on
#36 reads (+) should be ground and reads the same key on or off
#37 reads (-) with no buzz key on or off
at the main relay:
key on:
#30 (-)
#85 (-)
#86 (-)
#87 inside nothing
#87 outside nothing
key off:
#30 (+)
#85 (+)
#86 (+)
#87 inside (-)
#87 outside (-)
sometimes the main relay will rapidly click, but again without any pattern, just sometimes.
ALSO: i have run the MS seperate from the car on the stim with the laptop and let it run for 4 hours cycling it off and on with the toggle switch 50+ times and everything seems to be working correctly with it on the stim.
using this diagram to check the pin outs on the harness at the ecu (with it disconnected and key on and off as follows:
link to diagram http://www.megasquirt.325ix.com/MS_t..._motronic.html
with the ecu disconnected and the key on it reads as follows:
#2 no ground
#3 ground, but no buzz (indicating a weak ground)
#14 has no pin
#19 ground with key on
#24 ground with key on
#36 reads (+) should be ground and reads the same key on or off
#37 reads (-) with no buzz key on or off
at the main relay:
key on:
#30 (-)
#85 (-)
#86 (-)
#87 inside nothing
#87 outside nothing
key off:
#30 (+)
#85 (+)
#86 (+)
#87 inside (-)
#87 outside (-)
sometimes the main relay will rapidly click, but again without any pattern, just sometimes.
ALSO: i have run the MS seperate from the car on the stim with the laptop and let it run for 4 hours cycling it off and on with the toggle switch 50+ times and everything seems to be working correctly with it on the stim.
Comment