No Fuel Pump!

[SolidState]

Car quit on my way home on the highway. No fuel.

I have been working all night on it. So far I have:

Tested the pump out of the car on a 12v car battery. Tests Fine
Tested the voltage at the fuel pump/sender plug, which is inline with battery voltage.
Verified that the IRCM 'clicks' when the FP is jumpered and key is set to on.

I got the car running fine, and then while return after the shake down, it quit again. No consistent power at the leads to the actual fuel pump inside the tank.

My gas gauge is all over the place.

My thoughts are sender

Comments? I really need some help here. As of right now, I can't get to work.

 

[Mr Anonymous]

I'd suspect a harness issue. Check for signs of pinched wires, corrosion, etc. Could also be a problem with the CCRM that appears with temperature or vibration.

 

[SolidState]

I checked the harness as best I could. I am not seeing a drop in the voltage at the plug's pins.

Is it possible to get enough voltage but not enough current?

 

[92inPA]

Since both the pump and the gauge are malfunctioning, I would suspect a bad ground connection. As Chris noted, it's a harness problem.

 

[93rev2sev]

Check the harness next to the drivers seat. There are 2 large bundles with connectors that like to get corroded.

One definately contains the power to the fuel pump. It's the one with the smaller wires, IIRC. The one with the larger black with white stripe wire is the door locks and seat power. The other one has the fuel pump lead.

 

[SolidState]

I just went and checked all grounds. My Negative cable on the battery is a little loose, but everything else works correctly.

The gas gauge has been acting up for a while. Sometimes it'll go a good inch past FULL. I was going to swap the ASM behind the cluster to see if that helped.

I have wiggled every wire, removed and checked every ground I can find from the FORD CD, from the engine bay to the trunk. I am at a loss here.

The manual lists the grounds for the fuel pump as G301, located on the drivers side just in front of the gas/trunk release levers. It seems tight.

It also lists the ground for the gauge as G103, found on the drivers side apron right in front of the starter solenoid.

All other functions of the ICRM seem to function.

 

[Phoenix]

I just went and checked all grounds. My Negative cable on the battery is a little loose, but everything else works correctly.

The gas gauge has been acting up for a while. Sometimes it'll go a good inch past FULL. I was going to swap the ASM behind the cluster to see if that helped.

I have wiggled every wire, removed and checked every ground I can find from the FORD CD, from the engine bay to the trunk. I am at a loss here.

The manual lists the grounds for the fuel pump as G301, located on the drivers side just in front of the gas/trunk release levers. It seems tight.

It also lists the ground for the gauge as G103, found on the drivers side apron right in front of the starter solenoid.

All other functions of the ICRM seem to function.

That doesnt tell you that the CCRM is good. Each circuit all have their own relay , so if the fuel pump relay goes bad in the CCRM , the rest can still operate properly.

Im not saying its the ccrm , but I just wanted to clear this out for you. Do you have a M code CCRM handy to do a quick swap and see?

 

[SolidState]

No, unfortunately I don't.

The idle speed circuit works fine, and I get 12v at the plug.

I ordered a new sender. I am hanging my hat on the fact that the leads to the fuel pump weren't registering the same voltage as the plug for the pump/sender.

 

[SolidState]

Thanks for all you help guys.

Check the harness next to the drivers seat. There are 2 large bundles with connectors that like to get corroded.

One definately contains the power to the fuel pump. It's the one with the smaller wires, IIRC. The one with the larger black with white stripe wire is the door locks and seat power. The other one has the fuel pump lead.

Thank you for this. I checked there, but the green fuel pump plug was tucked under the main harness that it splices into, and I missed it the first time.

Turns out that plug was severely corroded and melted. With the car running, I moved the plug and the car stuttered to a stop.

 

[93rev2sev]

My pleaseure. It's always nice to be able to nail it on the head like that...

You were lucky my door locks stopped workin'. I found that plug 2 weeks ago looking for the reason my door locks stopped. Forgot to plug it back in and the car would not start...and I didn't hear the fuel pump...

 

[SHOZ123]

Just to add I have seen normal voltage in a circuit. But when put under load it will drop out. This can be caused by a few things but usually is corrosion or broken wires.

Think of a wire that has all but one strand broken. Under no load the voltage reads fine. Under load the single strand cannot carry the current and the voltage drop is so large the device is dead.

 

[SolidState]

I think that is exactly what it was. The idle speed circuit would go for a while, showing full voltage. But the pump wouldn't run.