1996 chevy c1500 silverado 5.7l, crank will not start issue

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#1
Make
Chevrolet
Model
C1500 Silverado
Year
1996
Miles
350000 on truck new engine has 400miles as well as rebuilt tranny 400 miles
Engine
5.7l
I am stumped with this one. I have a 96 c1500 with a new factory GM 5.7l engine I installed last year,(Original was a 5.7). due to issues such as hurricane Micheal and a severely torn rotator cup It took me dang near a year to get this thing done. engine has 400 miles on it. It was running fine with no issues. I went out and started it up one morning and it fired right up as always, I went back in the house for a few and when I came back out it had cut off. went to restart it and it would crank over but not start. so this is were I am. list of parts that were replaced during engine install: new dist, new MPFI system, new crank and cam sensors, new Throttle body sensor, Idle air control sensor, new MAp sensor, new oil pressure sensor, new cap and rotor, new spark plugs, new spark plug wires. and new cats as well. I have confirmed, that I have good spark and fuel. I have replaced both the Ignition coil and Ignition control module, since the issue and I went ahead and replaced the fuel pump with a delphi pump, the other was only holding 55 psI. new one is at 63PSI. I have pulled and inspected the distributor for any damage it has none, reset engine at TDC comp stroke #1 cyl and reinstalled dist. inspected both cap and rotor find no damage, I did swap with the ones from original engine which were working, and no change. I removed the upper peiluim and inspected the spider injection system for damage, leaks, and confirmed all 8 injectors pulsing and spraying fuel. I have check 12v at both the crank and cam sensors, as well as ground and signal, getting spark so I know CPS is good. I have spot check for compression 185psi on #s 1 and 2 cyl. I had 185 psi on all 8 cyls on the initial start up when engine was installed, and I was following manufacturer recommended break in procedure. I find it hard to believe this is a internal issue. Only code I have is a P0102 for the MAF sensor but I have had the sensor disconnected at times. I am at a lost with this thing. so I am open to suggestions I am going to drop the exhaust this weekend just make sure that it is not plugged for some reason as well check compression at all 8 cyl. pull valve covers and inspect valves rockers and rods.
 

billr

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#2
Two more "basics" besides checking compression and that there is spark:

1) Disable fueling, so it can't possibly be flooded, by pulling the fuse for injectors; then try starting fluid.

2) Check spark timing with a strobe light. Check more than just the #1 cylinder, I suggest doing all eight if there is a problem. (I kind of think crank-but-no-fire is a problem...) Make certain the spark is occurring on the correct stroke. One sure-fire way to do this is to remove a valve cover and use the timing light to observe the valve rockers.

I don't think a plugged exhaust would prevent it from firing completely; it would fire for a least a few seconds, similar to using starting fluid. I wouldn't wrestle the exhaust off of there.
 

nickb2

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#4
I am stumped with this one. I have a 96 c1500 with a new factory GM 5.7l engine I installed last year,(Original was a 5.7). due to issues such as hurricane Micheal and a severely torn rotator cup It took me dang near a year to get this thing done. engine has 400 miles on it. It was running fine with no issues. I went out and started it up one morning and it fired right up as always, I went back in the house for a few and when I came back out it had cut off. went to restart it and it would crank over but not start. so this is were I am. list of parts that were replaced during engine install: new dist, new MPFI system, new crank and cam sensors, new Throttle body sensor, Idle air control sensor, new MAp sensor, new oil pressure sensor, new cap and rotor, new spark plugs, new spark plug wires. and new cats as well. I have confirmed, that I have good spark and fuel. I have replaced both the Ignition coil and Ignition control module, since the issue and I went ahead and replaced the fuel pump with a delphi pump, the other was only holding 55 psI. new one is at 63PSI. I have pulled and inspected the distributor for any damage it has none, reset engine at TDC comp stroke #1 cyl and reinstalled dist. inspected both cap and rotor find no damage, I did swap with the ones from original engine which were working, and no change. I removed the upper peiluim and inspected the spider injection system for damage, leaks, and confirmed all 8 injectors pulsing and spraying fuel. I have check 12v at both the crank and cam sensors, as well as ground and signal, getting spark so I know CPS is good. I have spot check for compression 185psi on #s 1 and 2 cyl. I had 185 psi on all 8 cyls on the initial start up when engine was installed, and I was following manufacturer recommended break in procedure. I find it hard to believe this is a internal issue. Only code I have is a P0102 for the MAF sensor but I have had the sensor disconnected at times. I am at a lost with this thing. so I am open to suggestions I am going to drop the exhaust this weekend just make sure that it is not plugged for some reason as well check compression at all 8 cyl. pull valve covers and inspect valves rockers and rods.




































That is a whole bunch of information, my french brain went into overdrive.
 

nickb2

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#5
Who the f would put in a new crate gm engine in a 96? You need to do some VIN engine check. Spider, tbi, learn engine basics of back in 86. Or maybe this

 

nickb2

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#7
To all that read this, this post is screechy sketchy and until op actually tells me hoe he went to a conclusion that a new crate engine deserved the effort is beyond me. :oops:,