Maybe ECM problem, or should it be like this?

[LT1 Kayker]

I got a timing gun and tried to set the base timing on my 89 C1500, so I hook it all up and start it. Well the timing mark stayed in one spot, like if you pulled the signal wire out of the control module in a car to make it go into 'timing mode" or whatever they call it. Shouldn't the ECM advance and retard the timing depending on load, rpm and such? Cuz mine stayed in the one spot no matter what, and do I even have an ECM on this pile?

Also I tapped on the intake manifold and the timing stayed the same. Does this mean my knock sensor doesn't work, or do I even have one? gah!

[Mikado14]

Yes, your '89 should have an ECM. And do you really think that watching the engine idle with the timing light on the mark will show any variations unless you move the distributor or rev the engine? As far as the ECM changing the timing under load, rpm or whatever, yes, the ECM does alter the timing depending upon various sensor inputs, and if you are aiming the timing light at the mark at idle and then rev the engine light, you will see the mark jump, but timing is set at idle. I suppose banging the intake and looking for a timing change you are attempting to see if the knock sensor is working. You need to hit in the vicinity of the sensor.

Did you ever get your fuel problem fixed?

[LT1 Kayker]

Naw it still drinks about $50 of gas a week. But yeah, I was tapping in the right pot, and the timing mark stayed the same, and when i revved it up the mark stayed in the same spot. This means that its disconnected or not working right? Even at WOT it would stay in the one spot, like not move at all, and if it did it was less than 1 degree or just a figment of my imagination heh. So what should i do about this? the ECM signal wire is brown with a white trace I think...right? If I pull that out and it stays the same or runs better that means somethings wrong...right? Im not much into these crazy ignition systems all the wires and volts hurt my head.

[leftmullet4]

You have to disconnect the timing control wire "the ECM signal wire is brown with a white trace I think" otherwise the computer will automatically adjust the timing. Also as MIkado said you have to loosen the dist. bolt and move it until you get the desired amt of timing degree.