2004 astro van.started fine in the morning put rear brakes on now won't start.fuel pump works.when cranking over backfires through intake.didn't touch any wires when putting on rear br

Could be low fuel pressure. Should be 50psi min.

chk in line fuel filter for obstruction, also could be a lot of sediment in the tank clogging up the filter. Hope this helps you resolve your problem.

check for your cam sensor or crank sensor .

Have you checked Google I found this hopefully it's not your timing or it may be flooded but doubtful have you tried spraying starting fluid into the intake while cranking it

Do you notice crank when you turn over the key in ignition to start. Does it turn over but does not start, or no start nothing at all. ---------- If its not cranking and nothing happens when you turn the key, then its battery and starter related problem, both needs to be inspected.Either battery is not completely charged or its weak battery,that is not holding charge or its faulty battery or its connections are loose.-------- BUT if it is cranking and not starting, this clears that battery has juice in it and battery is doing its job and other possibilities needs to be checked. -------- The other possibilities are ,is the fuel pump coming on when you turn the key to start,is the spark is noticed at spark plug, is the check engine light coming ON. For more troubleshooting regarding this problem,click the link below:--- http://technoanswers.blogspot.com/2011/10/2000-chevrolet-astro-van-wont-start.html -------------- This should help.Thanks.Helpmech.

It won't die when pulling the relay because it has another power path to the fuel pump through the oil pressure switch . Fuel Pump Electrical Circuits Description and Operation watch this video on fuel pump control , shows chrysler first , ford ,then gm . wait for gm an he explains the oil pressure switch . Plus when it won't start ,don't guess or theorize ! Test what's missing ? check for spark , no spark check ignition system , coil's , ignition module , crank sensor etc... has spark ,do a fuel pressure test etc... don't think computer , when it won't start does the check engine light come on with the key on run not start . If light is lit ,nothing wrong with the cumputer . If want to fix cars you really should take some automotive classes . Test don't guess .Watch some other videos crank no start videos etc...

Try having someone pound on the bottom of the tank while your cranking if the van runs replace the pump.

With the upper plenum removed and spark disabled turn on the key and allow the fuel pump to prime while watching the fuel lines from the back of the intake to the injector. I suspect you lines are leaking. Have seen this before. ALOT.

by missing gas you pick up all the dirt in the gas tank if the gas pump dont start there nothing else then dirt in the gas pump if it was running good before so there no other reason then gas pump you try something get somebody to crank the truck at the same time go underneat the truck with a hammer hit the gas tank many time while the engine crank with the shot of hammer the vibration activate the gas pump check it out let me no pierre

I have the same problem, I replaced the fuel pump. Did NOT solve it. i was told that it is a computer problem. The computer is not sending electric to the fuel pump, by cranking it several times the oil pressure builds up and will over ride the computer and send power to the fuel pump. This is a common problem on these asrto vans.