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I have a 2007 C6 Base Vert with 26000 miles, all stock engine. Never had an issue in 4 years. HB replaced with Summit Racing last year as a preventive measure. All maintenance history up to date. Went to AutoZone to pick up some Mobile 1 and a filter. Planned to change oil when the wife and I came back from our road trip this weekend. Came out and car cranks but won't start. Dash goes black with only the engine light on. Gauges don't sweep. No codes found and red top battery tested good. Swapped the fuel pump relay and opened the fuse box under the hood and the connections look good. What should I check next? Crank sensor? Thanks
You need 3 things for the engine to start: fuel, timed spark, compression. You should be able to check for fuel pressure at the fuel rail. If pressure is good then move onto spark.
You need 3 things for the engine to start: fuel, timed spark, compression. You should be able to check for fuel pressure at the fuel rail. If pressure is good then move onto spark.
Will do. The gas cap is very loose. Third cap in three years.
Change the battery and still crank no start. When I reconnect the battery I get the following codes. I cleared them all but the Digital Radio Receiver comes back. I need a new Clock Spring because Bluetooth and steering wheel controls haven't worked since I replaced my steering wheel and pulled on the cable, but it ran fine after that. I do have an after market radio and amp. I'll check the spark and fuel pressure then pull the radio. Pulling the radio fuse did nothing. I have a Crank Position Sensor on stand by, ordering the Clock Spring today as well. .
Digital Radio Receiver U1000 Class 2 Data Link Malfunction
U1301 Class 2 Data Link High
You need 3 things for the engine to start: fuel, timed spark, compression. You should be able to check for fuel pressure at the fuel rail. If pressure is good then move onto spark.
Fuel pressure is 0 while even while cranking. Spark is good and constant.
Did you check the fuel pump fuse? It’s a 20 amp in #13 position in the under hood fuse box. If you hold the start button to put the car into run mode (not accessory mode), the gauges should sweep and you should be able to hear the fuel pump prime. To do this on an A6, leave in P and don’t press on the brake. Not sure on the M6, but it should be in the owner’s manual.
Did you check the fuel pump fuse? It’s a 20 amp in #13 position in the under hood fuse box. If you hold the start button to put the car into run mode (not accessory mode), the gauges should sweep and you should be able to hear the fuel pump prime. To do this on an A6, leave in P and don’t press on the brake. Not sure on the M6, but it should be in the owner’s manual.
I thought the fuel pump was number 20 below the fuel pump relay? The gauges don't sweep unless I crank it and after if fails to start they sweep.
Fuel pump won't prime with a jumper wire. I feel like I'm chasing ghost. I'll check the fuel harness in the left rear wheel well tomorrow. I bought this car so I could work on it but these electrical systems are frustrating. It will go to the shop if I can't figure it out soon.
Fuel pump won't prime with a jumper wire. I feel like I'm chasing ghost. I'll check the fuel harness in the left rear wheel well tomorrow. I bought this car so I could work on it but these electrical systems are frustrating. It will go to the shop if I can't figure it out soon.
Pins 87 and 30 are the terminals you want to jump which is the load side of the relay…do you have a 12 volt test light??
Pins 87 and 30 are the terminals you want to jump which is the load side of the relay…do you have a 12 volt test light??
Yes, I do. I'm getting 12v at the fuel pump while cranking. Now I need a 12v load to test the pump. I don't see how a car with 26000 miles could need a fuel pump.
Originally Posted by wjnjr
Check the fuel pump +12v power connector under the fuse box while you're in there.
I split the fuse box and didn't see an issue. I closed the contacts so all fuses and relay are nice and snug.
Yes, I do. I'm getting 12v at the fuel pump while cranking. Now I need a 12v load to test the pump. I don't see how a car with 26000 miles could need a fuel pump.
I split the fuse box and didn't see an issue. I closed the contacts so all fuses and relay are nice and snug.
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.
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.
Yes, I was checking the plug in the rear wheel well. I haven't tested the fuse with the light. Pin 87 and 30 show power but I haven't tested from the battery positive to 87. Will check both. Thank you so much.
06-01-2023, 07:38 PM
The Notorious Crank No Start Issue
