# 2008 Nissan Quest cranks but doesn't start



## Brainbucket (Mar 30, 2015)

Looking at the wiring diagram, fuse #35 with a 15 amp fuse in under hood fuse box supplies power to the ECM relay and crank, both cam sensors, ignition coils, and other stuff. I would check that first after I pulled codes. Either fuse #35, ECM relay, broke wire, ECM. If you have power at the coils on the red wire, then this is ok. Then I would check if the coils are being triggered by sticking a test light on coil pack #2, first on front left of engine standing in front of car, green/red wire and crank it. If test light flashes, it's working. If not, it's not being triggered. Then the fun begins. :vs_cool:


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## Bigplanz (Apr 10, 2009)

Any codes?


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## kuzya (May 2, 2010)

I checked the fuse and it is ok. There is 12 volts on red wire for ignition coil. No spark. No codes. I checked the signal wire on ignition coil with a test probe by cranking the engine. There was no signal while cranking. LET THE FUN BEGIN! What else can I check? Thank you!


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## kuzya (May 2, 2010)

Checked the crankshaft sensor and resistance is ok. The red wire is geeting power. Checked one of the camshaft sensors and resistance is ok and red is getting power. I will check the second camshaft sensor tomorrow. It is difficult to get to the second sensor.


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## kuzya (May 2, 2010)

I will also check for continuity between sensors and ecm. Anything else to check? Any other sensors? Thank you!


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## Brainbucket (Mar 30, 2015)

When you turn the key on, does check engine light come on? Can you see rpm's on scan tool? Check all fuses under hood and inside pass compartment. 1. Pull the ECM out of the cowl to test. While it is out, flip it over and inspect the bottom of the ECM case for excessive corrosion. Excessive corrosion can allow water into the case which could short out the ECM. 

2. Check powers, and grounds at the ECM. 

3. Check the 5 volt reference wires for potential shorts that could pull down the ECM.:vs_cool:


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## kuzya (May 2, 2010)

Couple of questions: i am not sure if the tool I have can read rpms. I can't start the minivan. How can the tool read the rpms? Does the ecm send the signal to the ignition coil?
Thanks.


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## huesmann (Aug 18, 2011)

If you're getting spark, a timing light with a tach should be able to give you an rpm, even if the engine isn't catching. It's just induction on the #1 spark plug wire.


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## Bigplanz (Apr 10, 2009)

Is the tach moving on the dashboard when you crank? If not, no crank signal.


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## kuzya (May 2, 2010)

No corrosion on Ecm and the service engine light is on when cranking. The tachometer is not moving when cranking.


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## Bigplanz (Apr 10, 2009)

kuzya said:


> No corrosion on Ecm and the service engine light is on when cranking. The tachometer is not moving when cranking.


No tach, equals no crank signal, equals no spark. Some cars will start on a long crank with no crank signal. After cranking for a few seconds, the PCM will use the cam signal instead. Not sure if Nissan does this. You might give it a try (long crank, that is).


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## kuzya (May 2, 2010)

Tested camshaft sensors and crankshaft sensors signal wire for continuity with ECM. All good. All sensors are getting power. Anything else to check on the ECM? Any other sensors?


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## kuzya (May 2, 2010)

Maybe I am not testing the sensors properly. I checked for resistance between the 3 connectors. I also tried a new oem crank sensor still nothing.


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## Brainbucket (Mar 30, 2015)

It almost sounds like a bad ECM but without being there idk.:vs_cool:


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## kuzya (May 2, 2010)

Tried cranking for a while and nothing. Is there a way to check if crankshaft sensor is working when it is plugged in and I am cranking the car? I only checked 3 wires on the ecm connector for continuity with the sensors signal wires. Should I check any other wires on the ECM? 
I checked all the fuses inside and starter fuse doesn't get power until I try to start. Is that normal? Thanks for all the help.


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## Bigplanz (Apr 10, 2009)

kuzya said:


> Tried cranking for a while and nothing. Is there a way to check if crankshaft sensor is working when it is plugged in and I am cranking the car? I only checked 3 wires on the ecm connector for continuity with the sensors signal wires. Should I check any other wires on the ECM?
> I checked all the fuses inside and starter fuse doesn't get power until I try to start. Is that normal? Thanks for all the help.


Yes, but you need an oscilliscope.


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## Brainbucket (Mar 30, 2015)

Check the resistance of the cam and crank sensors from the ECM connector to make sure that there are not a broken wire. And if memory serves me correctly, you should get about 1 volt while cranking. That tests wire harness and sensors. If all that pans out and your anit-theft isn't engaged, then it has to be ECM. :vs_cool:


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