With obd1, I've never had problems checking codes with jumper wire. Maybe there is always a first time, but, hasn't happened, yet. On older vehicles, I have seen mil lamp that didn't work for some reason. On those, I used a scanner to look at live engine data, see if anything looks out of kilter.
I'd have to check for injector pulse on the injector ground circuit, engine cranking. A noid lite will work. Also, if you have a digital multimeter that has a tach--duty cycle--dwell setting, I believe any of those will react to dc pulse. If the meter has a min/max setting, that should work.
Monday, November 10th, 2014 AT 3:06 PM