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Discussion Starter #1
Long time reader....

My ML wouldn't start last night. Tried other key and no change. IT cranks, but won't turn over. I figure either crank sensor or dreaded fuel pump.

So, I checked the rail (did not have a fuel gauge) and pressed the pressure thing and no fuel squirted out. Fuse is OK and I swapped the relay. Still no fuel in the rail.

Question is...does this eliminate the crank sensor and I should look no further and get the fuel pump replaced? I read somewhere that a bad crank sensor would also not allow the pump to run, but I can't find that thread now.

Thoughts? Help?

Thanks!
 

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I believe that is true. If it doesn't see a crank position sensor signal, it will not run the fuel pump. But, usually crankshaft position sensor fail only when they get hot. Usually if the car hasn't run for a while, they'll start up. It could be either one, though. Or it could be something totally different. How many miles are on the truck, and do you know if you have the updated larger capacity fuel filter already installed?
 

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Discussion Starter #3
Good points....
The crank sensor is original from `99 and it 'only' has 202,000 miles on it!

I bought the car in 7/99 new and in about 7/00 the fuel pump went and was replaced. I don't know the dates of the new style pump, so I don't know if it has been updated.

Although I have maintained this car, done the recalls, paid all the hefty bills and been frustrated with the issues (just like everyone else), it has been a great car when it has been running!

I was going to check for power at fuse 38 (iirc) to try and eliminate the sensor, but I am not sure if I should see power or not when cranking. The no-start was after sitting for a few hours and went back to it 1 and now 2 days later and still it won't turn over. I think that implies fuel pump....that and no fuel at the rail.
 

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Discussion Starter #5
sorry...

Hmmmm...semantics. Can I attach an audio recording?

I turn the key and it cranks for a few seconds, but does not start. I guess that means it won't fire. It sounds like no gas, but I have seen this same problem with CPS sensor on our jeep. It cranks and cranks, but no fire.

I can check for spark, but I don't hear the gas pump and the fuel rail is dry, so I figured fuel pump. BUT...I saw that a bad CPS would also not allow the pump to work.

My plan was to look at the fuse for the pump and see if it has power and measure the load on it. I read it should be 9A +/- 1.5A for a good fuel pump. Anything higher and it is a bad pump.

Any of this sound right to you?

THANKS!
 
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