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sprinkles08, ASE Certified Technician
Category: Mitsubishi
Satisfied Customers: 23112
Experience:  ASE Master and Advanced level certified. Factory trained with 17 years dealership experience
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97 mirage 1.8 manual. Replaced fuel pump two weeks ago,

Customer Question

97 mirage 1.8 manual. Replaced fuel pump two weeks ago, everything's been great. Now while on my way to work stop at gas station car won't start. Cranks fine. Runs with starting fluid. Now power to the brand new pump. Switched the two relays under the radio, I don't have on by the glove box.
Submitted: 3 months ago.
Category: Mitsubishi
Expert:  Mechanic01 replied 3 months ago.

Hello my name is ***** ***** I will be assisting you with all of your vehicle questions today. Give me one moment while I review your question and come back with a answer. Please be aware I do not know your skill level or abilities so I will be asking a lot of questions and in a lot of cases we will respond to each other quite a lot before we find a solution. As far as phone calls are concerned that is the system prompting you, not me, and they do cost more money, I prefer text but in some cases a phone call is required.

Expert:  Mechanic01 replied 3 months ago.

Are you able to check it with a fuel pressure test gauge?

Customer: replied 3 months ago.
No. Car doesn't have a port for one. I removed the FPR and there was barely a trickle of fuel in the rail. I just tried hot wiring the fuel pump directly to 12v I can hear it coming on. But still no good. As far as I can tell the ignition isn't firing either because with the pump hotwired there is now gas in the rail. Also, no CEL. Fuel gauge is reading 1/4, even with key out. Normally it resets to empty with the ignition off.
Customer: replied 3 months ago.
I thought given the discrepancy of the fuel gauge (never happened before) maybe I was just out of gas, so I added some fresh fuel. If I knew what sensor fed the ecu to signal the mpfi and fuel pump relays I could try that. But I don't know if the Ecu gets signal from the CAM, CRANK, THROTTLE position sensors, or somehow through the ignition failure sensor. Or something else. The lack of CEL - and the fuel pump doesn't just come on when you put the key in. So I know the Ecu isn't driven off the IgnOn state.
Expert:  Mechanic01 replied 3 months ago.

The sensor is #11 in the picture, we have to start somewhere, so this is as good spot as any.

1. Locate and test the ignition failure sensor.
Check for 12.0 volts key on at the Black/White (BK/WT) wire at the end terminal of the four wire sensor plug.

2. If there is voltage at pin four, check for 12.0 volts at pin three BK/WT wire of the sensor plug. If no voltage at pin three, replace the ignition failure sensor.

Customer: replied 3 months ago.
Keep in mind this is a brand new walboro 255 fuel pump. Worked perfectly for two weeks. And right up until about an hour before I submitted my question. Car was springing to life effortlessly. I check the FPR and the diaphragm is in tact. Car has compression. Also nothing was progressively worsening. No rough idle. No stalls. No hesitation. Perfect acceleration perfect 500-700 base ideal (depending on state of A/c compressor). Worked on second then won't the next.
Expert:  Mechanic01 replied 3 months ago.

Yeah I was thinking about that when I thought it could be that sensor I sent. We will figure this out!

Expert:  Mechanic01 replied 3 months ago.

let me know if the sensor checks out or not

Customer: replied 3 months ago.
Ok. Four wires. Pin 3 and 4 are both black with white stripe neither have +12 volts.
Expert:  Mechanic01 replied 3 months ago.

then the sensor is bad and needs replacement

Customer: replied 3 months ago.
that sensor controls the fuel pump relays too? I thought it only handle the ignition coils in case of misfire.
Expert:  Mechanic01 replied 3 months ago.

Im trying to pull that up in my diagrams, this is taking a moment

Expert:  Mechanic01 replied 3 months ago.

I cant find it in my database, ill have to open this up to see if another tech has that information

Customer: replied 3 months ago.
I've got the new sensor. I'm at work now and should be swapping this out at the gas station on the way home tonight. I'm just nervous because if this doesn't get the car started it's sitting there overnight. I'd like to explore all other possibilities before leaving work. I work at Advance Auto Parts.
Expert:  sprinkles08 replied 3 months ago.

Hello and welcome to JustAnswer!

There are quite a few things that can prevent the fuel pump from receiving power and it will require some testing to determine what is going on. It could be a wiring or relay issue, blown fuse, or the engine controller may not be awake.

Have you physically checked for spark?

Customer: replied 3 months ago.
Pulled one of the connecting plug wires, stuck a screwdriver in it and placed it near a grounded bolt. No spark.
No spark. No fuel pump or mpfi relay (they are identical relays and placed side by side on the mounting bracket).Engine is not spinning fast (like no compression), no spark, no fuel. Brand new OEM ignition failure sensor, BWD camshaft position sensor, fuel pump. MAS is plugged in, air filter clean, fuel filter less than two years old, spark plugs are NGK iridium less than a year old, the Mitsubishi body control computer was swapped out recently (about 2 months ago) for a junk yard unit because of a faulty blower motor speed control switch. All fuses, relays, diodes, and maxi fuses are intact.
Expert:  sprinkles08 replied 3 months ago.

I suspected you didn't have spark either.

Do you have a scan tool to see if the engine controller will communicate?