The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post - She won't fire up. Please help me! I"m at a complete loss!

jorgensensc · 06-30-2013, 07:15 PM

Hart,
The noid light I rented for the injectors is not coming on when I crank. So I don't think the injectors are firing. I didn't check the coils or the spark plugs yet. Will do that next.
Here's a dumb question. What is acceptable voltage drop to the ECM while cranking? The scanner shows 11.89 volts before cranking. Then drops to 9.75 while cranking. That is even jumpered to another car to verify I hadn't killed the battery. Goes over 12 volts, but then drops below 10 during cranking. Have read a couple of places that voltage drop to ECM can cause no start? Is this too large of a voltage drop?
Posted via Mobile Device

06-30-2013, 07:15 PM	#15
jorgensensc Registered User Join Date: Jul 2003 Location: Cypress, Tx Posts: 4,005	Re: She won't fire up. Please help me! I"m at a complete loss! Hart, The noid light I rented for the injectors is not coming on when I crank. So I don't think the injectors are firing. I didn't check the coils or the spark plugs yet. Will do that next. Here's a dumb question. What is acceptable voltage drop to the ECM while cranking? The scanner shows 11.89 volts before cranking. Then drops to 9.75 while cranking. That is even jumpered to another car to verify I hadn't killed the battery. Goes over 12 volts, but then drops below 10 during cranking. Have read a couple of places that voltage drop to ECM can cause no start? Is this too large of a voltage drop? Posted via Mobile Device __________________ 1972 C20 Suburban- Big Blue Betty '56 Chevy Bel Air Sedan- Frame up Restoration -What would you attempt to achieve if you knew you could not fail?- -I Refuse To Tiptoe Through Life, Only To Arrive Safely At Death's Door- R.I.P. EAST SIDE LOW LIFE