My eCU computer shot or is it the auto shut down relay?
Will not start,I hear no fuel pump action when key is turned on.checked
all fuses and fuel relays .And the dash gauges do not resgister with
key on postion. Added fuel straight into throttle body with no results .replace the auto shut down relay how? where's it located?
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Re: My eCU computer shot or is it the auto shut down...
It's under the hood usually on the driver side fender well. It's commonly known as an ASD Relay. Check the electrical part of the ignition switch. The "on" position of the ignition switch may not be working either.
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The fuel pump is powered from a relay. That relay is powered by the engine's computer ("ECU"). The relay is necessary to scale the low current control signal from the ECU into a high current switch to operate the fuel pump. The high current circuit will likely contain a fuse. That fuse or the fuel pump relay may be defective.
The fuel pump relay is activated for a few seconds when the ignition is turned on before starting the engine. If everything is working properly, you should be able to hear the fuel pump run for those few seconds before starting the engine. This is so the injectors have adequate fuel pressure before the engine is started.
IF BATTERY IS GOOD FOR SPARK THEN COULD BE A FUEL ISSUE, BAD FUEL PUMP WOULD NOT LET CAR START= NO FUEL. WHEN YOU TURN KEY HALF WAY YOU WILL HEAR PUMP GO ON RIGHT BEFORE YOU COMPLETE THE START CYCLE WITH KEY, NO NOISE BAD PUMP. THERE IS ALSO A RELAY THAT CONTROLS THE PUMP . MAKE SURE THAT IS GOOD ALSO
didnt specify year of vehicle most relays for tahoe is under hood and at side of dash on drivers side -- turn key to on and listen for hum of pump no hum try starting with starter fluid if starts test for power to connections ,pump and relay if power more than likely pump shot
The Automatic Shut Down relay is in the power disatribution center by the battery. It provides power to the ignition coil and the fuel injectors when it is turned on by the computer.Turn key to on and check for apower to the coil on the dark greeen wire. If you have power there, the relay is working. Don't believe it affects the pump on your jeep, but maybe. Do you hear the pump come on for 2 seconds when key is turned to on? It should come on to prime the fuel system, and then shut off. May have to be close to tank when someone turns key to on.
You have a ASD relay (Auto shut down relay) this is not a safety device you basically knock something loose.Turn the key on do you hear the fuel pump go on. If you dont check the fuses for a open condition and fusable link that are on the battery with key on wiggle battery negative terminal especially at the engine block and the frame ,same with the Positive part of the battery terminal .
Did you check for fuel pressure on the line from the tank while you had the filter off? Do you hear your fuel pump prime when you turn the ignition on? First I would listen for the hum of the fuel pump when you turn the key to the run position (not starting the engine) May have to get a helper and listen at the gas filler neck with the cap off. If you dont hear your fuel pump, check your fuses and relays. If the relay clicks when your helper turns the key on ( put your finger on the relay and ear down close to feel/hear the relay actuate)., and fuse is good, yet you do not hear the pump prime, I would say your fuel pump is shot.
If it is a diesel,check for fuel pressure coming off the direct drive pump hose while cranking the motor.
If you hear relays clicking sometimes and the jeep won't start, at those times, is the check engine light illuminated on the dash, or not? If no check engine light is on the dash, at times when the jeep won't start, your ecu is in need of repairs. The ecu sends power to the ignition and fuel relays and when the ecu starts to malfunction, the relays usually start clicking.
hope your not have the same problem that i had. i had to replace the ecu. my gauges wouldnt read and my odometer just flash and that would be it and the gas light would come on even though it had a full tank. but there one thing that you could try. replace the auto shut down relay first before you go and replace the ecu. the auto shut down shuts the computer off when you turn the key off. and if thats not working right then the computer wouldnt come on and the truck will not start and the fuel pump will not come on and the spark plugs will not fire.