QuestionHey Roland... I talked to you briefly the other day regarding my car stalling and not restarting....
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Question I recently put a new fuel pump in an 88' Chrysler New Yorker (4-5 months ago). I started the car the other day to warm it up and after a few minutes it stalled and will not start. It has spark. It has a 1/2 tank of gas. I hear the pump initially come on so I removed the line right before the fuel filter, no gas pushing through. Is there a pressure relay or some type of switch that may have to be reset or replaced?
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Answer Hi Chuck,
I checked the wiring diagram and found nothing unusual about the fuel pump. It is powered right off the autoshutdown relay which also provides power to the spark coil, oxygen sensor, and injectors on a dark green/black wire. If you hear it run for a second or so, then that means the wire is connected, and it is running as it should (cuts out after a second if you don't start and continue to run the engine...as a safety precaution). So I wonder if you have pressure in the gas line. It could be the pressure regulator has worn out and is allowing the fuel to return directly to the tank. It is located on the fuel rail at the engine (3.0L). The pump might have failed too. The pressure should be 48 psi, and after a little bit of cranking when you soon go to open the outgoing line to the filter you should have found it to be under pressure. If not, then either the pump isn't putting out fuel under pressure or the pressure regulator is not maintaining it. You could check for pressure in the line between the tank and the filter using a gauge while you crank it. The fuel pump has two internal check valves: one regulates internal pump pressure and regulates maximum output, the other near the pump outlet prevents flow in either direction when the pump is not operating. The pressure is supposed to be maintained such that when you first service the system you are supposed to first open the injectors enough (by grounding the harness) to allow the fuel pressure to drop so you don't have fuel spraying around the engine compartment.
Because you have spark while you are cranking it (is it for a full 5 second test?) that means the sensors for the engine rotation are getting through to the PCM which powers up the ASD.
Let me know if there is anything else you need.
Roland
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Roland,I've narrowed my fuel problem down to either a clogged screen in the fuel tank or the fuel pump relay. I'd like to try the easier of the two first but I'm having trouble pinpointing the relay. I was told it was located in the engine compartment on the driver's side. Is it right in front of the strut mount side by side next to another relay?
AnswerHi Chuck,
The three relays starting inboard on the strut are: starter relay, radiator fan relay, then around the corner on the fender is the "fuel pump relay" though in reality this is the autoshutdown relay which provides power to the fuel pump, the spark coil, the injectors, and the oxygen sensor, all on a dark green/black wire. You can tap into it at the spark coil + post to see if the relay is putting out the 12v on that wire to all the modules including the fuel pump while you are cranking over the engine for 5 seconds. If not, then if you don't have a failure of one of the sensors in the distributor which would cause an 11 or 54 code, then you may have a failed relay. Did you check for codes with the ignition key? "On-off-on-off-on and leave on" doing this in 5 seconds or less? Then watch for the check engine light to begin to flash, pause, flash, etc.
Count the number of flashes before each pause. Repeat. Then group the numbers as they came out in pairs. They come out in serial order. 55 will always be last because that is the code for end of readout.
So, I have given you somemore to do. Please let me know what happens.
Roland
