Truck won't start - HELP
11-30-2017, 01:37 AM
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Truck won't start - HELP I put a 2003 5.3 motor in a 84 Chevrolet truck. It cranks but it won't start. Hot at coils and injectors but no spark at the plug. The pcm grounds are good. Any suggestions?
11-30-2017, 02:21 PM
#2
Is the computer from the same vehicle that the engine came out of? Later engines had the 58X reluctor ring, and the earlier engines had 24X. If you have a computer mis-match, it won't fire the plugs.
Also, what about VATS? Did you disable it? Do you have HP tuners?
Does it try to start and run, but then stall again?
Can you hook a scanner up and while cranking watch to see that the crank position sensor is putting out a signal? Your CKP sensor should be right by the starter on the block. Check it to make sure it is plugged in. Also, what color is your CKP sensor? The plastic part of the sensor will be white/gray, or black. That may help us diagnose this issue as well.
Does the tach move at all when holding the key in the start position with the engine turning over? That will also tell you quickly whether or not you have a crank signal getting back to the computer.
Also, what about VATS? Did you disable it? Do you have HP tuners?
Does it try to start and run, but then stall again?
Can you hook a scanner up and while cranking watch to see that the crank position sensor is putting out a signal? Your CKP sensor should be right by the starter on the block. Check it to make sure it is plugged in. Also, what color is your CKP sensor? The plastic part of the sensor will be white/gray, or black. That may help us diagnose this issue as well.
Does the tach move at all when holding the key in the start position with the engine turning over? That will also tell you quickly whether or not you have a crank signal getting back to the computer.
