Removing Wiring From ECM/TB Harness

Dirtbuster1

Dirtbuster1

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May 13, 2008
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Georgia
I was talking to Bird concerning my CFI problems. After installing the headers & removing the Air Pump, the engine & ECM just have not been in sync. While making my new TB harness today, I was trying to decide if I could remove the wires that go to the Air Control Solenoid, the EGR Control Solenoid, & the Air Switch Solenoid? I think that I need to reinstall the EGR Solenoid, but the 2 others have me stumped. If you trace out the wires, there is a pink/black wire to supply power. The other wires return to the ECM, but what is there function. IF these circuits are not looped back together, is it possible that the engine will stay in open loop. The returning wires are telling the ECM something, otherwise they would not be there. I could probably splice them back together, but what is the correct thing to do.
 
Dirtbuster1 said:
I was talking to Bird concerning my CFI problems. After installing the headers & removing the Air Pump, the engine & ECM just have not been in sync. While making my new TB harness today, I was trying to decide if I could remove the wires that go to the Air Control Solenoid, the EGR Control Solenoid, & the Air Switch Solenoid? I think that I need to reinstall the EGR Solenoid, but the 2 others have me stumped. If you trace out the wires, there is a pink/black wire to supply power. The other wires return to the ECM, but what is there function. IF these circuits are not looped back together, is it possible that the engine will stay in open loop. The returning wires are telling the ECM something, otherwise they would not be there. I could probably splice them back together, but what is the correct thing to do.
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Do you have those parts still? Why not just plug them in, and see if it corrects it. Unplug, and see if you get a check engine light. The check engine ight is on in open loop. Does the lamp come on at startup and go out?
 
The CEL never came on with the AIR pump disconnected. However the car did not idle up when cold as it should have. That's what makes me think that something was not right. Is there a way to tell if the engine is going in to closed loop. I think I still have some data from WINALDL that I could possibly compare it to. The CEL is coming on before cranking. The wiring harness definetly looks like it had been repaired several times. I have made a new harness, with the exception the Air Pump & EGR circuits. It seems that I ordered the wrong connectors for that circuit. I still feel that those connectors give a feedback loop to the ECM once the car goes from hot to cold, otherwise I don't think that the Pink/Black wire would feed power to those circuits,
 
Dirtbuster1 said:
The CEL never came on with the AIR pump disconnected. However the car did not idle up when cold as it should have. That's what makes me think that something was not right. Is there a way to tell if the engine is going in to closed loop. I think I still have some data from WINALDL that I could possibly compare it to. The CEL is coming on before cranking. The wiring harness definetly looks like it had been repaired several times. I have made a new harness, with the exception the Air Pump & EGR circuits. It seems that I ordered the wrong connectors for that circuit. I still feel that those connectors give a feedback loop to the ECM once the car goes from hot to cold, otherwise I don't think that the Pink/Black wire would feed power to those circuits,
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ASSUMING the cel circuit is functioning properly, the car warms up in open loop, and after 2 minutes goes into closed loop. If it does not, the CEL comes on whenever the loop is open.
 
Jeff,

What is the function of the Air Pump circuits. I since they are feeding the ECM for some reason. After losing 4 ECM's, and not seeing the CEL light come on, it makes me wonder. I guess I will leave the wires in and see what happens. What would happen if I jumped the wires at the plugs to simulate the circuit closing. I might just hook up the Air pump circuits to see what happens. I will update the results sometome this weekend when I get my valve covers finished.
 
Dirtbuster1 said:
Jeff,

What is the function of the Air Pump circuits. I since they are feeding the ECM for some reason. After losing 4 ECM's, and not seeing the CEL light come on, it makes me wonder. I guess I will leave the wires in and see what happens. What would happen if I jumped the wires at the plugs to simulate the circuit closing. I might just hook up the Air pump circuits to see what happens. I will update the results sometome this weekend when I get my valve covers finished.
Click to expand...

The air pump circuits I ASSUME you mean are the AIR pump diverter valve solenoids. These are loads, and should NOT be connected directly. I DOUBT they are sensed as connected.
When energised, they direct the air to either the manifold injectors, the converter, or vent to atmosphere.
 
Bird,
I agree on that now. I did some reading last night on the GM Service manual. It says that the Air Pump senses temp from the CTS & vacuum from the EGR valve. I think that I need to keep the EGR solenoid installed. Closed loop is only activated by the CTS & O2 sensor. One other thing that I read that was interesting was that the Speed Sensor controls the IAC motors settings. I might need to look into that circuit to see if something has a problem. I know that the speed sensor is working by reading it with WINALDL.
 
Dirtbuster1 said:
Bird,
I agree on that now. I did some reading last night on the GM Service manual. It says that the Air Pump senses temp from the CTS & vacuum from the EGR valve. I think that I need to keep the EGR solenoid installed. Closed loop is only activated by the CTS & O2 sensor. One other thing that I read that was interesting was that the Speed Sensor controls the IAC motors settings. I might need to look into that circuit to see if something has a problem. I know that the speed sensor is working by reading it with WINALDL.
Click to expand...

Yep. After the time delay has passed, if the oxy sensor and the CTS is satisfied, your in closed loop as long as the perameters are in spec.I knew the speed sensor helped control T/C lock up, did not know about the IAC function.
 
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