Excessive Fuel Consumption

mojo racing

Active member
I'm hoping someone would have some ideas as I know I'm overlooking something. I went to a new position at work that now requires me to drive 30 miles. I put my truck back to completely stock except a MSD coil and a Mad Ramper CAI. So my issue is, in a 60 mile round trip my truck burns over 1/2 tank of fuel. I have pulled the codes and the only one that's in the memory is 332 insufficient EGR flow that was due to a stuck valve but now fixed. Any thoughts? :?
 
Stop & go 30 mi or hwy 30 mi? That's a 5 mpg diff. My front tank reads 1/2 when it's actually 2/3 so do a fill-up and see how much fuel you actually burned.
 
If you're ready for a real answer... ;)

Ford published several documents about this exact question. It's a few minutes' worth of reading, but this & the links in its caption will probably help you figure out where your gas is going:



But Fred is right - the fuel gauge is not a meter, so you can't base your MPG calculations on it. And Shaun's question is also worth checking.
 
I'm the first one to say the fuel gauge is never accurate but the tank was full and when I saw how much fuel it was using I stopped and topped the tank off and it took 9.8 gal to fill back up. Fred, all highway at 70 mph. The tanks aren't cross flowing either. This just happened all of a sudden just a few month ago I took it on a trip and it was completely normal.
 
On the one day a year I decide it's safe to take mine out of the garage and drive it to the office I typically use (per the gauge) about 1/4 of the rear tank ... that's just about a 21 mile and 20 to 30 minute drive round trip.

As I recall on the front tank I can get about 170 miles out of it.

I'm thinking you may be experiencing an aged float and your gauge indication is a tad inaccurate.

But ... gather some empirical data ... what Fred said.
 
Well, if you're really getting only 6 mpg then yes, that's cause for concern. Read thru Steve's post for starters - lots of good stuff there.

Check the obvious stuff first - plugs fouling? Exhaust smell like fuel? Hold a clean white rag over the exhaust pipes at idle for a few seconds then check the rag for carbon, fuel smell.

Assume you've already checked fuel system for leaks?
 
Thanks for the input guys! Fred, I did check the fuel system for leaks and I did the rag on the exhaust thinking maybe I had a leak in the exhaust upstream of the o2 sensor causing it to get a false reading and sending it askew. I haven't pulled any plugs yet it's been too dang hot! I plan on trying to do that Saturday morning. But something I did notice, not sure if this would matter but the temp gauge was reading really low (below the normal line). My mechanical gauge was at 170* when the gauge reached 190* it was slightly higher but just barely in the normal range. Could thar cause the EEC to try to adjust the fuel and cause a rich condition?
 
Yes, if the truck is running at that temp then it would be staying in open loop configuration and would causebitvto use more fuel. Posibly a thermostat that is stuck open.
 
Yes, if the truck is running at that temp then it would be staying in open loop configuration and would causebitvto use more fuel. Posibly a thermostat that is stuck open.

The truck is running at 190, the temp gauge sensor is malfunctioning or the gauge is not reading correctly......that's on my Saturday list as well....that and large amounts of bourbon!
 
The truck is running at 190, the temp gauge sensor is malfunctioning or the gauge is not reading correctly......that's on my Saturday list as well....that and large amounts of bourbon!
The factory thermostat I believe is a 190, so that seems normal to me.

Sent from my SM-G920V using Tapatalk
 
...the temp gauge was reading really low... Could thar cause the EEC to try to adjust the fuel and cause a rich condition?
No, the EEC is not connected to the gauges, so a gauge fault can't affect the EEC. The EEC uses the ACT & ECT. This caption explains how to test them:

 
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