goodburbon

Let's start recording some data.

For example.

I just had the engine monitor on both of my trucks. One is getting 16mpg, the other 18+.

I noticed that the one getting less mpg had a manifold pressure of about 6.5# absolute at cold idle while the one that gets more mpg has a manifold pressure of about 8# absolute at cold idle.


at sea level


There is also a very noticable performance difference between the two, even after loading the very same " stock" tune.


I'll take a more in depth look at the differences tomorrow. pressure when not running, intake temps, exact idle pressures, 0-60 times, hot idle pressures, whatever else I can think of.

try not to opine in this thread, lets see if we can't discover a trend to the trucks, maybe something as simple as a map sensor miscalibration.

sllydderrr

Subscribed.

I hope this thread produces ripe fruit.

I have not done any measuring nor do I have the equipment to do so. All I have is the productivity screen and the torque app. So: I shall shut up and not talk now.

TuxBlackEB

X2

Theocoog

I've subscribed, but after 23,500 miles, I'm averaging exactly what the sticker says I should average: 17 mpg.

I'd be glad to contribute any data that the Torque app can provide. What would you like to see?

MadocHandyman

So is the one with less # at the manifold basically bringing in less intake air?
I'm curious about this because I still wonder if many experiencing poor mileage have intercoolers full of water.

engineermike

Even though I'm not in this club, I think I could offer some suggestions.

Poor fuel economy could be caused by too much drag or poor engine efficiency. Consider first determining which one it is.

Too much drag could be caused by malfunctioning stability control, malfunctioning ABS, low tire pressure, etc... To test it, maintain a steady 75 mph. Release the throttle and start a stopwatch. Time it to see how long it takes to decelerate from 75 to, say, 55 mph. Compare this to others to see if there are significant differences.

Poor engine efficiency can be caused by lots of things. Reading data can be helpful, but I urge you to get a computer scanner, scangauge, or any number of smartphone aps to read engine data. Pick a speed for everyone to get data. Faster is better because it's very difficult to hold the throttle steady enough at lower speeds. So, again, maintain a steady 75 mph and record data like: manifold pressure, A/F ratio, rpm, TC status, fuel flow rate, and ignition timing. Cam timing, knock retard, and EGT would also be helpful, but I haven't been able to read this with my scangauge. This can tell you if the engine is under increased load (higher manifold pressure), if you're getting false knock (low ignition timing), or just identify differences between high-mpg trucks and low-mpg trucks that could point you in the right direction.

Hope this helps.

sku11ey

How about crapy gas stations that put 89 in in all + tanks. I worked at one in the 80' that put unlead in the leaded tanks. Is their a portable breathalyzer for gas octaine. Pore gas could be the factor.

engineermike

It's been discussed many times, but octane makes no difference in fuel mileage except a rare few specific cases. Ethanol content, however, makes a difference.

Even still, I don't think octane or Ethanol content is you guys' issue, unless you're getting ripped off and running more than 10%. Many folks running 87 E10 gasahol are still getting much better mileage. I just made a 2400 mile trip, running 87 octane gas with Ethanol (the crappiest stuff you can buy) for 1800 miles of it. My overall average for the trip was 23.7 mpg's loaded down. The pure gas (87) tank was over 24, but the Ethanol gas (87) was still 22+ mpgs.

I suppose it's possible some of the stations are diluting the gas down with more Ethanol. Ethanol is cheaper, so they will clear more profit. They do sell Ethanol meters you can analyze the gas with. I've heard of this being done and some stations were selling >10% Ethanol gas.

Bills96TA

Is there a program for Fords like HPtuners? I haven't really got into the tuning side of fords so I don't know but with the GM's this program can be setup to monitor almost any engine function and log the readings as well. I would think it would be an amazing tool to figure out what is going on as you can see everything, save the data and then play back or export to Excel and look for gross irregularities.

EBinMT

California (maybe others) uses extra oxygenators on top of Ethanol in their fuel for pollution control further lowering mileage.

I have read that in some cases the e10 we buy in many cases can actually 15-20% ethanol.

I have noted as well that when I fill gas in North Dakota or Wyoming I have much lower fuel mileage. I attribute this to ethanol blend vs the Exxon station I frequent that I know that has 0 ethanol.

Montana is supposed to mark pumps that have ethanol, yet when I fuel at the Cenex station near my home that has no ethanol markings I get much lower MPG in all my vehicles. This is the one that boggles my mind.

One more thing I have noticed. Highway rpm. My 2011 with 3.31 gearing would do 20 at 70, 18.5 at 79. My 2012 with 3.73 will do 19 at 70, and 15.7 at 79. I think the dramatic drop can be attributed to the rpm at cruise rising above 2000.