jlwardn

I first checked for the pressure problem I waited 15 secs after turning the key over to give the fuel pump time to pump gas....then I cranked to start.....It took several attempts to start but with a little gas it will start. It seemed not to help by waiting the time...I tried several times. I then replaced the coolant temp sensor. The first time I started it cold it did fire up. Then next cold morning however it did the same....crank start and stall....it takes a little gas pedal to keep it running and once it is running for about 10 secs it does just fine. It has new factory Nissan plugs......and checks out ok for idle speed on Consult. Any one got other ideas??? I know there are lots of posts but the 2 suggestions did not work for me....all seems to be a problem under 35 degrees....on warmer days it starts just fine....Thanks...

Daniel B. Martin

I don't see anything wrong with pressing on the gas pedal if it helps your engine start. Just avoid causing it to race when it does fire.

Daniel B. Martin

Idea #1) You replaced the wrong sensor. There are two of them, right next to each other. One drives the dashboard gauge, the other sends signals to the Engine Control Module.

Idea #2) The replacement sensor was BOB (Bad Out of the Box). Every technician has experienced a few BOB parts. It's frustrating.

Idea #3) The Idle Air Control Valve - Auxiliary Air Control valve is misbehaving. For an engine to start it must have fuel and air mixed in the right proportion. When your foot is off the gas pedal the butterfly valve in the throttle body seals tightly. The air the engine needs to have in order to start comes from the IACV-AAC valve. If that valve isn't opening the engine won't start unless you press down on the gas pedal. We call it "the gas pedal" but on modern fuel injected engines it's really "the air pedal".

Here's the factory service manual component inspection procedure for the IACV-AAC.

1) Make this test with the ignition key OFF. Disconnect the IACV-AAC valve harness connector.

2) Looking into the valve connector with the latch at the top, you will see two rows with three terminal positions in each. They are numbered 1-3 (top row, right to left) and 4-6 (bottom row, right to left). Check resistance between the following terminals.
2 and 1.
2 and 3.
5 and 4.
5 and 6.
At a temperature of 68 F, the reading for all measurements should be approximately 30 ohms.

3) Reconnect the IACV-AAC valve harness connector.

4) Remove the idle air adjusting unit assembly (IACV-AAC valve is built-in) from engine. The IACV-AAC valve harness connector should remain connected.

5) Turn ignition switch ON and OFF, and verify that the IACV-AAC valve shaft smoothly moves forward and backward. If NG, replace the IACV-AAC valve.