2005 F150 fuel gauge nightmare...

66glide · February 24, 2017

Bear with me folks. This is a long one. On June 14, 2016 at 495,888 km the customer requested that we replace his fuel pump/module assembly. He had a complaint of stalling and hard starts at times along with an erratic fuel gauge. He requested no diagnosis and we installed a Carter brand pump assy.

July 25/2016 at 501,538 km he was back complaining of fuel gauge erratic readings. IDS showed no related codes for the fuel level circuit. The red "park" brake light was always on in the cluster, too.

Light "taps" on the cluster would cause the gauge to change position from 30% to 80% or wherever. We installed and programmed a reman cluster from Ford.

We could not retrieve data from the old cluster...it would not transfer data to IDS. We had to use "as-built" for the truck to program the new cluster. Now the red "brake" light is out, and everything appears ok. Release to customer.

January 13/2017 @ 515,817 km, the complaint is fuel gauge is erratic/intermittently drops to "empty". IDS shows cluster code B1201. On clearing, the code would return instantly. Resistance testing at the cluster showed 158 ohms...about right for a full tank. We replaced the cluster a second time and programmed using data received from the removed cluster. No codes, gauge works, released vehicle.

Feb 6/2017 @ 517,908 km same complaint of gauge dropping to zero. Again, B1201 in cluster and P0463 in PCM. Frustrated, we decided to warranty the pump/sender assembly. While apart, we supplied power and ground through the fuel gauge wiring at the tank connector and lit up a sealed beam at the cluster connector to "load" the wiring for circuit integrity and voltage drop testing. We then plugged in the sender and actuated the float through various positions and the cluster responded with the proper readings based on float position. All passed. Since the concern is intermittent, we released the vehicle.

Feb 17, 519,240 km same complaint and codes. We installed and programmed another cluster. I drove it 40 miles with the heat on high because the customer insists it only happens with the heat on. No failure, so I released it again. I just got a phone call saying it dropped to empty three times.

I really don't know where to go from here. Is it possible there is a bad batch of reman clusters out there? I'm not buying it. I am aware of the sulfur contamination TSB...maybe I need to put an OEM Ford sender in? But two bad new aftermarket ones? I dunno.

Should I just get out of the business and open a flower shop?

Help!

66glide · February 26, 2017

Anyone? Opinions?

Bruce Amacker · February 26, 2017

I'd be suspect of the aftermarker sender. If the driver is a techie you could run a wire to a DVOM in the cab and see if the resistance reading drops out when the problem occurs. In one of my classic cars I put 3 aftermarket senders in before finding an OE VDO which are out of production.

I'm an OEM guy, learned the hard way after fighting way too many aftermarket parts. Man, the stories I tell in class..........

Good Luck!

Sometimes this business sucks, but what don't kill you makes you stronger.

:grin:

66glide · February 26, 2017

I'd be suspect of the aftermarker sender. If the driver is a techie you could run a wire to a DVOM in the cab and see if the resistance reading drops out when the problem occurs. In one of my classic cars I put 3 aftermarket senders in before finding an OE VDO which are out of production.

I'm an OEM guy, learned the hard way after fighting way too many aftermarket parts. Man, the stories I tell in class..........

Good Luck!

Sometimes this business sucks, but what don't kill you makes you stronger!

I agree. OEM is my first recommendation for most tune-up and electrical parts.

mrbudge · February 27, 2017

If this is a flex fuel vehicle it may have a dc/ac converter in series with the fuel gauge sender. There is a 12v power supply wire going to the converter that likes to get corrosion in the wire, the voltage drops and the gauge drops out. The converter is in the harness near the sender. Since this truck is a 2005 it should not have it, but I have seen stranger things. It may be worth taking a look.

66glide · February 27, 2017

If this is a flex fuel vehicle it may have a dc/ac converter in series with the fuel gauge sender. There is a 12v power supply wire going to the converter that likes to get corrosion in the wire, the voltage drops and the gauge drops out. The converter is in the harness near the sender. Since this truck is a 2005 it should not have it, but I have seen stranger things. It may be worth taking a look.

Thanks, Dave. It is not a flex fuel vehicle. I can't say we cut the loom looking for a converter...it might be worth a look. Maybe a non-flex fuel vehicle inadvertently got the converter harness. How big is the converter? Can it be hidden/covered by the loomed harness? We did not notice any bulge or larger area in the harness, but then we were not looking for an AC/DC converter.

Then again, looking at the diagram, when we powered the sealed beam through the circuit, we should not have achieved the bulb lighting up through the converter...I don't think...I am not up on the internals of an AC/DC converter.

mrbudge · February 27, 2017

The converter is taped into the harness near the sender. It is just a small box 1 inch square and maybe 1/4 inch thick or so. I agree it should not have one but we had one here that we fought with the gas gauge for a while, so I opened the harness looking for wiring problems and found the converter. You will see the harness has a fat spot if it has a converter in it.

66glide · March 14, 2017

I am quite confident that the problem was the female pins in connector 220B. I disassembled the connector and did a "pin pull" test onto the cluster pin. I "adjusted" the female terminals, re-assembled the connector and released for trial.

Just goes to reinforce verifying the basics. I ASSUMED (we all know what that does) that this connector, being in a clean and relatively vibration free environment, and not carrying any heavy electrical load, would not suffer pin fit issues.

I will report back and verify a fix in a couple of weeks. Thanks to everyone for the input!