I am helping someone with a 1988 Isuzu Trooper (gasoline). I will not
pass emissions test for the idling part of the test, and it seems to
have low power and feels like it "floods" when you first press on the
gas to go, instead of the engine winding up smoothly.
The owner just finished replacing several different parts, including
the EGR valve and O2 sensor, spark plugs and wires, mass air flow
sensor, and it gives no error codes now. It runs a little better but
I put a timing light on it and the timing appears to be way off, the
mark is maybe 30 degrees to the passenger side as you look down at the
crank. I did pull off and plug up the two vacuum tubes that you are
The timing is so off that you can't twist the distributor enough to
bring it to the correct spot. I even thought that I might have it on
the wrong plug wire but I was on the No. 1.
I noticed that as the engine was reved, the timing stayed steady
instead of moving as it would if the ignition timing advance was
operational. I think that the problem is that the ignition timing is
not advancing, and that a previous mechanic set it far in advance when
tuning it "by ear" and got it barely running that way.
Does this make sense ?
What part controlls the ignition timing advance, that I can replace ?
Thanks in advance,