Skip the auto shop - Our mechanics make house calls

Q: no pulse on injector so not getting any gas

asked by on

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

A: Three things are needed in order for the in...

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.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: The clutch pedal has lost all tension what should i check?

The clutch pedal going all the way to the floor without disengaging the clutch is caused by a failure in the hydraulic clutch linkage. There is a clutch master cylinder (and reservoir) and a slave cylinder down underneath near the...

Q: Replaced master cylinder and brakes still going to the floor and not working. Bed both master cylinders and each wheel.

If your vehicle has ABS brakes, it is possible that there is an air bubble in the ABS system. Many vehicles require a special bleeding procedure for vehicles with ABS. This will require you to do the bleeding in a...

Q: Check Engine Light P0420 trouble code

Hi there, thanks for writing in. Typically, a P0420 code (catalyst efficiency insufficient) is the catalytic converter not properly functioning. Chances are, the Check Engine Light going off and then back on, it's still the P0420 code that is present....

Related articles

What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.