1992 K1500 5.7L Loud Bang and All Dead

1992 K1500 5.7L While Driving Loud Bang and All Dead. My wife took the truck for a food run and never made it back. She said the truck made a loud bang from under the hood and she lost steering and brakes.
I assume the engine quit. I am trying to figure out what went wrong so I can repair it myself before winter as I cannot afford to take it to my local garage right now. Anyway the battery was extremely low when I met my wife at the side of the road, probably from her trying to start it. The injectors are firing and it seemed to want to start for a minute while cranking with the last of life from the battery. I am assuming good spark and timing and from the bang figure it might be a timing chain. Truck mileage is approx 135k. Seeing how tomorrow is Sunday I plan on going up to the lot and cking things out a little further. How can I tell if the timing chain is indeed the culprit? It did not seem to turnover very fast as I would think it would if the chain were broken. If remove the cap and verify that the distributor turns when cranking, does that mean the chain is good?? I am not sure what the distributor runs off of the cam or oil pump shaft?
Thanks for any advice in advance!! This has always been a great newsgroup. Whoops my nose got brown..... Thanks JRE
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On Sat, 13 Nov 2004 19:17:12 -0500, "Mastermech"

if the rotor turns, the timing chain hasn't broken. the power flow from the crank to the distributor is as follows: crank to camshaft to distributor to oil pump. I wouldn't assume that you've got spark unless you've observed it.
--Bret
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Mastermech wrote:

functioning chain.
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Fastest reply I have ever seen. You dudes are great. OOPS more brown on my nose!! I will ck for rotation in the A.M. If the distributor rotates I will look into Spark. Thanks Again JRE
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sounds like a classic bad fuel pump
the bang was a backfire from lean mixture

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The mileage is probably about prime for the fuel pump as well.
Brian
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Fuel pump was replaced last year with a gm pump, but I will keep that in mind.
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It wouldn't hurt to check and see that the timing chain didn't jump time also.
Brian
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Check the hei module inside the distributer. My truck did the same thing last week.
Unfortunately, there is no way to test exept for replacing it. Anyone else know how to test the hei module?

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CKed this A.M and injectors are firing, Rotor is turning, but will not fire off. I disconnected the timing connector and still would not fire off. I will go back up this afternoon and ck for spark with my spark tester. Assuming I have spark how would I ck to see if the timing chain jumped a tooth?? Thanks Again,and again, and again. JRE
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The two easiest ways to do this is #1 remove the spark plugs so the motor turns easier, take the valve cover off the drivers side and turn the motor until the intake valve closes. Then take a stiff wire or a thin long screw drive and place it in the #1 spark plug hole while SLOWLY turning the motor by hand until the piston is at top of the stroke. The rotor button should then be pointing right at the #1 cylinder terminal on the distributor cap.
#2 method is bump the motor over with the starter and holding a finger over the #1 spark plug hole until you feel compression. Then SLOWLY turning the motor by hand use the wire or screw driver to feel your way to the top of the piston travel. Again the rotor should be pointing at the #1 spark plug terminal on the cap.
Brian
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Thanks for all the input. I guess the "loud bang" threw me a little. Anyway I cked for spark and there was none, rang out the coil and pickup both were good so I replaced the Ignition Module. All Fixed Thanks Again JRE
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