Q: I have a 1976 Cadillac Eldorado 500 with an 8.2L fuel-injected engine. The engine cranks but doesn’t start. Both fuel and spark are present. What could be preventing the engine from starting?
– Rod T McClashie from Mesa, Arizona
A: Hi, Rod. When you say the engine is getting fuel, I’m guessing you mean that there is good fuel pressure. What you might be missing, however, is injector pulse—the onboard engine management system “pulsing” the injectors on.
Your vintage Cadillac has a fairly modern electronic fuel injection system that includes an electronic control module (ECM), sensors, and fuel injectors. The ECM uses input from the sensors to determine when to fire the injectors.
One of the easiest ways to check for injector pulse is with a noid light. You simply disconnect the electrical connector from the injector, then insert the noid light into the female side of the connector. Crank the engine and monitor the noid light. Repeat this test on a few different cylinders. If the light does NOT illuminate during testing, there’s no injector pulse, which indicates the ECM is not commanding the injectors on.
From there, you’ll need to determine why the ECM is not pulsing the injectors. The issue could be a faulty sensor (e.g., engine speed sensor), a wiring problem, or an issue with the ECM itself.
The other possibility is that you have an engine mechanical problem, such as a damaged timing chain, preventing the engine from starting. But if the engine cranks normally, I would lean more towards a lack of injector pulse.
Good luck!
Product Mentioned in this Guide
Engine Control Module
Fuel Injector
Timing Chain
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