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Chevy Forum: Please help !! 93 2500 350 5.7 - no spark or start
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  #1  
Old 02-18-2013, 03:54 AM
WaltR WaltR is offline
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Default Please help !! 93 2500 350 5.7 - no spark or start

HELP! PLEASE! 93 2500 350 5.7 no spark - tried everything! New distributor (came w/new cap,rotor,pu coil,icm) new coil,plug wires. Timed 4deg BTDC. Spraying gas - power to red/pink primary wires on coil plugs - No power to white wires (no flash/pulse coming back from ICM to coil) NO SPARK from coil or to cap - no spark to plugs. Even put another working ICM in distributor. Fuel pump and relay working - no popped fuses in panel - all wires ohm good from coil to distributor - AHHHHHHH!!! WHAT COULD BE WRONG? I CAN NOT FIGURE THIS ONE OUT!? ECU? PLEASE - need an expert !!
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  #2  
Old 02-18-2013, 10:06 AM
zora zora is offline
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Default Re: Please help !! 93 2500 350 5.7 - no spark or start

try this link

http://easyautodiagnostics.com/gm_ic...n_module_1.php
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Old 02-22-2013, 08:23 AM
Chuzz Chuzz is offline
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Default Re: Please help !! 93 2500 350 5.7 - no spark or start

Have you checked for loose, broken or corroded ground wires under the hood?
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Old 03-16-2013, 12:27 PM
WaltR WaltR is offline
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Default Re: Please help !! 93 2500 350 5.7 - no spark or start

There has been more developments. Truck starts and runs (had distributor in wrong). It runs fine over 1000 rpms but as soon as I let off pedal, it stutters and dies. Took off TBI - checked press reg. and injectors all good, replaced base gasket / getting good spray. Pulled map vacuum hose went to full rich and black smoke (which it should) new cts, all vacuum lines good, new fuel filter, power to both injectors, fuel relay clicking right, unplugged 02 sensor no change, new distributor (pick up,cap,module, rotor) new coil, don't think it is ecm as it won't idle at all - even before it gets to the ecm loop, checked all wires and plugs, tps pulling.05 v at key on, fuel pump kicking on at start, IAC replaced with new one and no change, no fuses popped in IGN or fuel relay, timed with brown wire unplugged, RUNS GREAT OVER 1000rpms? I AM STUMPED ANY SUGGESTIONS?
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Old 03-17-2013, 11:55 AM
zora zora is offline
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Default Re: Please help !! 93 2500 350 5.7 - no spark or start

You correctly set the ignition timing after reinstalling the distributor? I found this and apparently you have to disconnect power to computer after setting timing.

Locate the single wire black connecter, ( Tan wire with black stripe ) on the left side of fire wall above heater box, There will be a black cover You will need to remove to see it. Start engine and allow to warm up, Then turn engine off and unplug wire, hook up timing light, Pos. and Neg leads hook to battery the other goes to # 1 Plug wire ( FRONT PLUG ON DRIVERS SIDE ) Restart engine and set timing to the specs. On the sticker under the hood 0 TDC is the timing. Then turn engine off and plug connecter back up. Then unhook NEG. Battery cable on battery for 15 min. Then hook back up and start engine.
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Old 03-17-2013, 08:37 PM
WaltR WaltR is offline
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Default Re: Please help !! 93 2500 350 5.7 - no spark or start

Ok, timed it correctly - still no idle unless over 1000 rpms
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Old 03-17-2013, 09:10 PM
WaltR WaltR is offline
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Default Re: Please help !! 93 2500 350 5.7 - no spark or start

The new distributor was purchased on the web - aluminum body with a different style of pickup coil (not the "ring" like the old dist) that has many contacts that spin and pass in front of a main sensor. Module looks the same. New cap and rotor came with it as well. Could it be this dist is not compatible? I don't have the cash to buy another. Not even sure if this problem is ignition related? Let me back up - had trans repaired(no reverse) then was flooding and hard starting. Unplugged CTS and started (replaced CTS) seemed to work ok - the truck just died while driving one day. Thought it ran out of gas, but was not giving any spark. Removed dist, and broke pickup (not plastic ring, metal star - looking part that attached to shaft). Shaft looked warped anyway so bought what I described above. If I barely touch pedal it will start and run pretty well - but right under 1000 rpms it just dies. Just ran vacuum test on MAP today and checked out fine - TPS tested out as well. Cleaned 02 sensor no difference. Sprayed carb cleaner around intake manifold no difference. I am still stumped, please - any ideas?
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Old 03-18-2013, 09:37 AM
zora zora is offline
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Default Re: Please help !! 93 2500 350 5.7 - no spark or start

Have you ever done a compression test? read the section on the IAC

http://www.justanswer.com/chevy/2bi4...tbi-found.html
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Old 03-18-2013, 06:44 PM
WaltR WaltR is offline
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Default Re: Please help !! 93 2500 350 5.7 - no spark or start

Not yet, I will but don't think that is it, because it runs decent in upper rpms, and I have even driven it like this (2 footed) to the parts store. It just sputters and dies as soon as the needle goes under 1000 rpms. No matter what I have tried, it refuses to have a steady idle. Checked oil switch and fuel pump relay circuits today all working correctly. Pulled all nuts off junction block terminals and cleaned( not dirty) pulled stud for neg terminal on intake manifold and wire brushed. Getting ready to tear into and drop tank to see what's going on with pump, strainer, sending unit and grounds in there. I can't seem to find what it is ??
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Old 03-18-2013, 06:47 PM
WaltR WaltR is offline
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Default Re: Please help !! 93 2500 350 5.7 - no spark or start

Also pulled injector terminals off one at a time - still the same thing (less power revving) but would BARELY idle at approx 1-2 rpms one or the other unhooked.
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