E350 Fuel gauge issues

sierraoneill · 01-17-2021, 12:04 PM

Hi

I’ve got a 2007 V10 E350 with fuel gauge issues. I Went and replaced both the pump/fuel sending unit thinking that was the issue, but after doing so I’m still getting inaccurate readings. On a full tank, just after filling up, it will go from completely full and then read empty, but not throwing any codes (I was getting fuel sender codes on the old sender unit). Anyhow, after driving and a few on and offs it will go from completely empty to just a bit over 3/4 tank (probably should read1/2 tank) it will never drop below 3/4 tank.

Any ideas? Cluster issue??

I’ve yet to pull the pump again and manually move the float on the sender to see what happens on the gauge, but any thoughts?

carringb · 01-17-2021, 12:12 PM

Check the fuel pump connector for corrosion. You can also put meter on the sender pins. Expected range is 15 ohms empty to 150+ full. If you get a good reading there, and there’s no corrosion, it might be a gauge. If you have a scan gauge, I think one of the x codes is fuel level %. Could verify using that too.

sierraoneill · 01-17-2021, 01:16 PM

Thanks,

I’ll check the connector again. I did give it a good blast with contact cleaner, but will look again as well as checking resistance on the pins while moving it full range once I pull it again.

Any thoughts that a gauge issue would prevent any codes from being thrown? I have a SCT Tuner/programmer and it is not seeing any codes.

carringb · 01-17-2021, 01:46 PM

On the CAN-BUS Fords, the fuel gauge strategy is a little weird. The sender mostly tells it when it's full, then the PCM counts injector pulses to meter the fuel gauge. That's how it keeps it from fluctuating with hills like our older vans. And it also why adding 5 gallons won't always register on the gauge. And also why it even has a fuel sender code. But it might be ignoring the sender at this point, if it "knows" its bad. This might be one of those items where you need to actually pull the battery lead for 10-15 minutes to clear the KAM (keep alive memory) and make it recognize the new one. Does the SCT let you do a gauge sweep test? That would be easiest way to rule out the cluster.

The pickups have a gauge-sweep mode built-it, where you hold the trip-reset button while starting up, until the test lights go out, then it sweeps when you release the button. Not sure if this work on the E-series.

sierraoneill · 01-17-2021, 05:31 PM

Well, went for the easy access fix first... one hour disconnect, then filled the tank, after about 2 minutes of driving away from the gas station, it dropped to empty. I saw that the SCT lets me do a KAM reset. I tried that too... no change..

I also tried the Gauge sweep trick, but it didn’t do anything by holding the reset button and turning the key on.... I need to google further as maya be I didn’t do the right process (kind of like the on/off 5 times to program the key fobs).

Next step i guess will be to clean the connector much more diligently before breaking the seal on the tank to pull the new pump / fuel sender assembly and to manually move the float and check resistance.

I always love it when the easy fix works, not so lucky this time I guess.... I might just disconnect the battery for a few days to ensure the KAM fully resets.