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No, you’re not using the 12 volt test light to test the pump…first does the test light illuminate of BOTH test points on top of the fuse ??…visual inspection is not how it’s checked if that’s how you checked it…next remove the FP Relay…with test light connected to battery POSITIVE probe terminal 87 (G7) of the relay…and don’t shove the tip of the test light in there or you will spread the terminals and have pin fitment issues…if the test light illuminates the circuit from the relay through the pump windings and then to ground is good…87 is the rear terminal closest to the engine and windshield looking at it from the fender…you said you’re getting 12 volts at the pump ??…you checking at the connector in the rear wheel well ??…getting 12 volts doesn’t mean the pump will run…you have to load test the power and ground side…the circuit has to carry the current that the pump draws which is about 5 amps…this is a 5 amp headlight bulb I use to check these circuits…I’m substituting the bulb as the pump.
I don't get a light from the battery positive to 87 but do get it on the pin right below, closest to the engine and furthest away from the window. I have a Tech2 clone but just learning how to use it. I pulsed the fuel injectors and saw fuel when connecting the gage to the valve but still no pressure. No codes other than U1000. Digital Receiver has a status of 1 but other modules have a status of 0. Relay appeared active while cranking. Thanks again and let me know if there's any else you recommend. Giving it one more week than to the shop it goes. I'm really missing it. Never had an issue in 4 years.
I don't get a light from the battery positive to 87 but do get it on the pin right below, closest to the engine and furthest away from the window. I have a Tech2 clone but just learning how to use it. I pulsed the fuel injectors and saw fuel when connecting the gage to the valve but still no pressure. No codes other than U1000. Digital Receiver has a status of 1 but other modules have a status of 0. Relay appeared active while cranking. Thanks again and let me know if there's any else you recommend. Giving it one more week than to the shop it goes. I'm really missing it. Never had an issue in 4 years.
You were checking pin 86 which is the G102 ground (control side ground) ...if no light on 87 you will need to access the fuel pump connector in the aft left wheel well to make some more checks…at the wheel well connector after jumping pins 87 and 30 at the relay you will need to see if you are getting power down there from the relay…if you put a headlight between the gray and black wires at the wheel well connector and if it illuminates you most likely have a bad pump..you can directly apply 12 volts and ground directly to the pump connector and see if the pump turns on.
You were checking pin 86 which is the G102 ground (control side ground) ...if no light on 87 you will need to access the fuel pump connector in the aft left wheel well to make some more checks…at the wheel well connector after jumping pins 87 and 30 at the relay you will need to see if you are getting power down there from the relay…if you put a headlight between the gray and black wires at the wheel well connector and if it illuminates you most likely have a bad pump..you can directly apply 12 volts and ground directly to the pump connector and see if the pump turns on.
I am getting power at the connector. I can see the fuel level and power to the fuel sensors on the pump with the Tech2. Will 12 volt start the pump if there's are power at the sending unit?
I am getting power at the connector. I can see the fuel level and power to the fuel sensors on the pump with the Tech2. Will 12 volt start the pump if there's are power at the sending unit?
Like I said previously getting 12 volts with a test light or multimeter doesn’t tell me much…if has to be able to handle the current….hook up a load like that headlight bulb between the gray and black wires at the connector…if the light illuminates brightly the wiring from the relay down to that connector is good so you have a bad fuel pump...you can also jump power and ground to the pump side of the harness to see if it runs.
Just some data from the Tech2. Cam and Crank Sensor looking good. Ran some more injector pulses to try and hear the fuel pump but I didn't hear anything. I smelled gas after the test and it wasn't near the injectors. One of my O2 sensor voltage is a bit low. Fuel tank pressure seems low. If something stands out please let me know.
Just trying to figure out what you mean by “Ran some more injector pulses to try and hear the fuel pump but I didn’t hear anything”…you need a test light on the fuel injector control wire while the engine is cranking to see injector pulse…which O2 sensor voltage is low ??…most of these screen shots look like the engine is not running…the 450mv you see is a “bias voltage”…somewhere around 450…that is what you should see…which one is low ??..a Tech 2 will not show you fuel pressure…if you jump terminals 87 and 30 at the relay and the pump doesn’t run you have troubleshoot that…I explained this in earlier posts…a Tech 2 won’t help you…with the engine off you should see 1.5 volts on the fuel tank pressure sensor…this is atmospheric pressure for most GM cars looking at the tank pressure.
Just trying to figure out what you mean by “Ran some more injector pulses to try and hear the fuel pump but I didn’t hear anything”…you need a test light on the fuel injector control wire while the engine is cranking to see injector pulse…which O2 sensor voltage is low ??…most of these screen shots look like the engine is not running…the 450mv you see is a “bias voltage”…somewhere around 450…that is what you should see…which one is low ??..a Tech 2 will not show you fuel pressure…if you jump terminals 87 and 30 at the relay and the pump doesn’t run you have troubleshoot that…I explained this in earlier posts…a Tech 2 won’t help you…with the engine off you should see 1.5 volts on the fuel tank pressure sensor…this is atmospheric pressure for most GM cars looking at the tank pressure.
The GM Manual fuel pump trouble shooting guide says to attach fuel pressure gage, pulse injectors with Tech2, look for pressure and listen for the fuel pump to prime. I can also see the Fuel Relay going active. I jumped the relay a week ago and the pump didn't go on. The only thing I haven't done is to try and jump the pump to see if it runs but I'm not sure how to do that because the pump is getting power. I can see the sensors and fuel level with the Tech2. I'm looking for the test to turn the fuel pump on with the Tech2. Why do you think the Tech2 is useless? Isn't this what the repair shops would do?
The test you are using is not for fuel pump troubleshooting…that is the injector balance test to see if the injectors are flowing evenly…if you go to…Powertrain…ECM…Special Functions…Output Controls…Fuel Pump...here is where you can find it…I believe this is the path from memory…you have to get this notion out of your head that it can’t be a fuel pump because of the low mileage…that has NO bearing on the pumps ability to work.the Tech 2 is a great diagnostic tool but you have to know how to use it for what you are trying to diagnose…the pump just needs the proper current and a good ground to operate…that’s all…these pictures show the current flow from my pump without the engine running (no load) vs with it running at 9.45 Amps...Fuel Tank Pressure is not fuel pump pressure...it has to do with the EVAP system...air pressure in the fuel tank.
It was indeed the fuel pump. Took it to MasterWorks in Madison Heights MI and they got it back to me in four days. Three days was waiting on the pump to come in. Highly recommended Corvette Specialists.
06-13-2023, 05:20 PM
