TBI pulse going nuts tachometer twitch

1994 CHEVROLET 3500
172,000 MILES • 7.4L • V8 • 2WD • AUTOMATIC
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C3500HDLIFE
Truck listed above is a c3500hd.
As I start truck it doesn't start; I look at TBI barrels are filled with gas. I pull pulse sensor on top of injectors start truck reinstall pulse sensor on truck with a good amount of rpm's pulse is erratic and fuel injectors spray skipping. ides high then low, I know it's something with pulse or maybe bad injectors or faulty ECM.
May 7, 2020 at 11:33 PM
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ASEMASTER6371
  • ✓ASE Certified Mechanic
  • 52,796 POSTS
  • ASE Certified Mechanic
Good morning,

You did the testing for this already.

When you disconnected the injectors and the fuel did not flood, that means the injectors are good.

The erratic operation indicates the ECM is the issue.

I would replace the ECM. I attached the part from Rock Auto. You need to match the numbers on the ECM. This is a plug and play module.



Roy
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May 8, 2020 at 8:03 AM
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