1988 220 micro computer

[etecbull]

Engine runs great when computer bypassed, but how long can it run like that? Does anyone repair the micro computers on these engines?

[rodbolt17]

may not be the computer.
in bypass spark is still generated by the charge coils and cdi.
iys con*****ed by the fixed pulser coils.
you should note an increased idle speed as ign timing is now fixed at 7*BTDC.
top speed cannot be reached as timing is fixed.

the computer modifies base fixed timing based on various input signals.

[etecbull]

May not be computer

How do I figure out if is the computer or something else. Can I send the computer somewhere to have it checked out.

[99yam40]

Test things that can be tested according to the service manual to eliminate all you can

[rodbolt17]

no place I ever heard of to test the computer.
I have never seen one fail personally.
however I have only been doing this type work for a living for only 30 or so years.

I have seen knock sensors fail, ground and 12V feeds fail.
TPS fail, pulser coils fail and such whatnots.

ALL the computer did on that model,for ign, was MODIFY the base ign timing curve.

myself I would carefully test the inputs as that computer is rather expensive new and hasn't been used in about 25 years.

kinda like your 25 yr old car or TV.

[etecbull]

1988 micro computer

Thank you for the help, I don't have a manual, but I can check many of the inputs. Based on your statement it would seem ok to operate the engine with the computer bypassed for awhile.

[rodbolt17]

not really.
the ign timing will be to far advanced for normal idle and wont advance far enough for proper ign at high speeds.

but its your motor. fix it or tear it up.

[etecbull]

220 micro computer

Thanks, I will find a manual and do the best I can to check it out.