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I just finished swapping engines in a 2004 Impala LS 3.8 v 6. Old engine had 236K on it and blew a head gasket bending a rod. After installing the new engine I am not getting any gas to the motor. Relays and fuses are all good. All connectors are good and I have found no loose or broken wires. The schematics show a low/no oil pressure switch or relay in the fuel pump circuit but I can not locate this part. Are they talking about the low oil sender unit down by the oil filter> I have tried jumping this sender to see if it made any difference. No joy. Any ideas short of a new fuel pump???

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have you checked out the operation of your fuel pump relay in the underhood junction box? It is powered by the F?PMP RLY fuse (15A) in the same junction box. the computer sends out power on the dark green and white wire to turn on the relay. Don't go jumping to conclusions that it is the fuel pump before you check to see if the fuel pump is getting a good power and ground and then it is not working. I know this may sound like a stupid question but you do have gas in the tank right? Hey, it has happened before... I had a Nissan Titan truck come in for a crank no-start and the gas gauge said 1/4 tank. Scanned the engine for codes and it had a code for fuel tank level sensor. I took the filler cap off for the tank and put a funnel in the filler and had another person cycle the key while I listened by the funnel. I could hear the fuel pump run. (fuel pump comes on to prime the system before you turn to the start position) I added some gas and then tried again, it started right up. It was out of fuel.

have you scanned the car to see if you have any codes that may turn off the fuel pump relay? How do you know you are not getting fuel? did you measure the fuel pressure and volume? Did you verify that you are getting fuel injector pulse while you are crank the engine? Do you have good ignition spark to the cylinders? (security will shut off the injectors. so, even if you have good fuel pressure the gas won't get to the cylinders.

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If the engine turns over but doesn’t start running, the first question you need to answer is whether your fuel tank is empty. Even if your fuel gauge says that you still have some fuel, the gauge may be on the blink. If you’re not out of fuel and your vehicle lost power before it died, fuel is probably not getting to the engine. Here are some additional reasons that specific types of vehicles may not be getting enough fuel.

Gasoline- and diesel-powered vehicles: If you have a modern vehicle with a multiport or sequential fuel injection system, either the fuel pump isn’t pumping fuel or the ECU isn’t triggering the fuel injectors. In either case, a professional will have to troubleshoot it.

Ethanol, methanol, and flex-fuel vehicles: The potential problems are the same whether the vehicle is running on pure gasoline or on gasoline mixed with alcohol: Either you’re out of fuel or the fuel pump or fuel injectors aren’t working properly. In any case, there isn’t much you can do but call for help and be patient until it arrives.


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