Q: no pulse on injector so not getting any gas

asked by on May 21, 2016

not getting any gas in tbi put in new ecm but still no pulse
My car has an automatic transmission.

Three things are needed in order for the injector to spray fuel: 12 volts from the ECM fuse, ground from the ECM, and fuel pressure.

A simple check to test the injector and fuel pressure is to provide 12v and ground manually to the injector. You should hear it click and fuel should spray.

  • Warning: Be careful! Connect the injector side first to prevent a spark near a fuel spray.

You’ll have to cycle the key to prime the fuel system to do this more than once. If it does not spray, the problem is the injector or no fuel pressure. The injector should have around 1.3 ohms of resistance, if it is open or zero resistance, it is bad. The injector could be totally clogged as well. Fuel pressure should be 9 to 13 psi.

Check the wiring to the injector. You can check the positive side with a test light with the key on. If that is good you will need a noid light to check the negative pulse from the ECM. A test light will not work for this. Connect the noid light, and crank the engine. If it blinks, the wiring is good.

Did you check the spark on this engine? If there is no spark as well, the pick-up coil in the distributor is the most likely problem. This tells the ECM how fast the engine is turning. No pick-up coil input, no spark or injector pulse.

If the pick-up coil is the problem, you might be better off replacing the distributor. You have to disassemble the distributor to replace the coil. This can be difficult due to carbon and sludge baking on the the distributor shaft. Plus, you will get a new ignition control module as well. If you need assistance with this diagnoses and repair, reach out to a certified mechanic who will be able to replace your distributor and fuel injector if necessary.

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