870 2006 fuel lift pump

[Rawze]

I have seen dozens of people describe those exact symptoms...

I have seen plenty of people replace their lift pump,.. only to have it take out the gear pump because they disturbed everything and old pieces of the lift pump went straight into the gear pump, sheering its input shaft.

* The symptoms are -- engine cranks and sputters a bit,.. then dies,.. and it does not matter what they try,.. they can't get it to keep running. they blame the ecm,.. they blame the wiring, they blame a hundred things to no avail.

-- Although I don't recommend this, I have seen people do it ... engine runs fine when ether (or brake cleaner) is sprayed into the intake manifold to help keep it running, but it just can't seem to keep running on its own.

Here are some things to check first though, they are...

* First make sure your getting oil pressure reading in the dash on the oil pressure gauge while cranking. It usually takes 10 seconds or so of cranking for this to happen. -- No pressure in the dash at all,.. == possible bad ecm or power to ecm.

* make sure coolant, etc. is up at normal level and that your not getting any engine shutdown codes in the ecm via Insite.

* Monitor the fuel pressure in insite while cranking. It takes a minimum of 50 psi from fuel system for the engine to fire off while cranking. It takes a minimum of about 250 psi for it to keep running once it gets going.

* If your getting the above 50 psi,.. but it is not going up to 250+psi after it fires off,.. the gear pump is most likely bad, just like described above, and for the reasons mentioned in previous posts.

--------HOWEVER-------!!!!!!


I have also seen plenty of people who end up with the ecm of intermittent engine dies syndrome too,.. BUT this usually is a very different scenario,.. It usually involves the engine running just fine for a few minutes after it has sat and everything cools off,.. or for 30 minutes,.. or for a day or so,.. and then engine dies without any warning or codes or anything, putting you in the middle of the road randomly.

you can check to see if this is your problem by turning on the keyswitch, listening to the gear pump run,.. and tapping the top of the ecm with something to see it the lift pump suddenly dies. here is some references to that scenario...
http://rawze.com/forums/showthread.php?t...8#pid25328

(sluggish cranking problems)...
Lastly, if the engine is not turning fast enough, it will not fire off. Could be weak starter, but before assuming it is the starter or batteries, bar the engine by hand. make sure it turns without excess resistance. If it has high resistance, remove the drive belts and see if it frees it up a bit. It is common for a bad alternator or AC pulley to cause a lot of lag in engine start. - if the engine has been sitting for a long time, someone should also check the turbo turbine to ensure it spins freely. That can make one not start either.