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1575 Views 23 Replies 4 Participants Last post by  esean19
Came out of the store and no start. Kept cranking with no sign of firing up. Towed home. Replaced fuel pump relay, checked fuses, no luck. Removed air filter housing, poured some gas into air intake and it fired up and running for few seconds smoothly. Repeated several times and fired up every time running normally then died. Concluded not getting fuel. Ordered and replaced both fuel pump and fuel filter breaking my back with no results. No codes. No history of not firing up. Have had the car for about 5 years. 160K miles. Both batteries new. I thought because it fires up when I pour gas in the intake it shouldn't be any of the sensors or the key not communicating. What else should I look into? I don't have any advance tools or software just a basic MB code reader. If aware of any previous discussions here, please guide me to. Please help. Thank you.
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If you have a mechanic's stethoscope, put it on, hold the sensing rod on a fuel injector, and have a helper try to crank the engine. You should hear the injector clicking - no clicking no fuel, no run.

If you don't have a stethoscope, you can try it by holding a metal or wood rod against the injector and your best ear, but a mechanic's stethoscope is $20, and will be useful many times.
There are fuses and relays involved, both for the pump and for the injectors. There should be a chart for the fuses and relays in your truck - if not, search using Duck-Duck-Go, Google, or your favored search engine to find the information.

The fuel pump just supplies fuel at 55psig to the injector rails. Absolutely no fuel enters the intake or the combustion chambers other than by being injected by computer-controlled fuel injectors.

There is at least one fuel cap on the injector rails. Slightly loosen - do not remove - the cap, then turn on the ignition very, very briefly. If the fuel pump works, you will be leaking or spraying gasoline into the engine compartment, which is very dangerous. A quarter of a second is plenty of time to see if fuel is being delivered to the rails.
The correct fuse/relay chart should be in the tool kit in the spare tire well.
Leakage around the taillight housing is a known problem.
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