wont start

[duckhead]

Hi Guys
I have a 2004 LS V8 the other morning I was going to work went to pull out of garage it started then staled. Will not start again sounds funny. I think it is crank or cam sensor any tips on how to check them . I do hear fuel pimp come on I read if you crank it and tach does not move it is crank sensor. 160 thousand miles new coil packs and plugs last summer.
Thanks Marty

 

[joegr]

You need a good OBD II scan tool to verify the crank and cam sensor operation. Set it to graph those, and watch as you try to start it.

I don't know why you suspect those, they hardly ever fail. More likely items would be the MAF, marginal coils, fuel pump, ...

First basic trouble shooting. Unplug the electrical connector to the MAF. Does it start?
Spray starting fluid into the intake, does it fire a few times (start or nearly start)?
Pull a coil out and put a spark plug on it. Hold the end of the plug against the metal of the engine. Run the starter. Do you see arcing in the plug gap?

 

[duckhead]

You need a good OBD II scan tool to verify the crank and cam sensor operation. Set it to graph those, and watch as you try to start it.

I don't know why you suspect those, they hardly ever fail. More likely items would be the MAF, marginal coils, fuel pump, ...

First basic trouble shooting. Unplug the electrical connector to the MAF. Does it start?
Spray starting fluid into the intake, does it fire a few times (start or nearly start)?
Pull a coil out and put a spark plug on it. Hold the end of the plug against the metal of the engine. Run the starter. Do you see arcing in the plug gap?

well have not checked for spark if the MAF was bad wouldn't it run bad prior to failing
2 pump does come on when key is turned on I guess it could be bad filter tho
3 coils and plugs last year and no miss fires prior to that trans does shift hard once in a blue moon but I think not related to it
yes getting starting fluid after work today can was MT last night was going tpo do that
Thanks for the input

 

[joegr]

MAF can fail suddenly, such as if a bug or something gets on the wire.
Hearing the pump does not mean it is pumping (though it probably is).
What brand coils?

Anyway, need fuel, spark, and compression to run. Need to figure out which one(s) you don't have and then go from there.

 

[duckhead]

MAF can fail suddenly, such as if a bug or something gets on the wire.
Hearing the pump does not mean it is pumping (though it probably is).
What brand coils?

Anyway, need fuel, spark, and compression to run. Need to figure out which one(s) you don't have and then go from there.

right on will post what I find tonight coils were not motocraft I forget what they were

 

[duckhead]

cant really understand it but I got it running. Yes thanks for the unplugging MAF sensor I really think that's what did it. Tried a few times after I unplugged it it did stumble once. So I shot some go go juice down it still unplugged. It then fired up I plugged back in the sensor it wanted to stall but did not. Shut it down and fired back up a few more times. Then I cleaned the sensor with CRS MAF cleaner just to be sure.

So Thanks a ton joegr I say you fixed it or what do you think change out the sensor it did have some carbon on it but after it was shiny like the outside of sensor.

 

[joegr]

Do you by chance have an aftermarket intake/filter?

 

[duckhead]

No motorcraft I all ways buy motorcraft oil and other parts I have bought except for coil packs they were OEM parts but Rock Auto parts damn gasbottle cap on where you fill antifreeze was sixty bucks dealer item plastic housing motorcraft for thermostat and all other parts. Premium gas also it's weird I'm sure it will do it again maybe bad gas it smelled like old gas when it fired up it's my daily driver for work so gas was just put in two days prior ?????
Thanks Marty