Nissan Repair: 94 sentra cold start, soleniod, cold start

Question
runs excellent except on cold start ,done tune up and cleaned air idle valve and replaced temp sensor and still won't idle when cold i checked the fast idle soleniod  and it getting no voltage any other ideas to check why the comp. will not activate cold start ?  tested TPS and MAF and both were in specs thanks  Allen

Answer
Allen,

If you replaed the correct temperature sensor then I would be looking at backprobing the circuit to the ECM.  You could have a relay failure on the ECM mother board.  That is, it is easier to pull a ground than to push power.  So, the way the quad circuit on the mother board works is to ground the cold start circuit when it receives the signal from the temperature sensor.  You could check the circuit by bridging the switch.  If the cold circuit does not activate start checking the wires back to the firewall.  Also, I have seen some crazy ECM issues where disconnecting the battery and then disconnecting and reconnecting the ECM harness, with the battery disconnected and reconnecting it and then hooking up the battery and the car works great.  Check these and email me back if you need more.  Try the harness connector first.