What's my problem?

[scexy]

Hello All:
I joined sometime ago but lost track of the forum...

I have a 2000 Expedition XLT, 5.4L, with a Kenne Bell Twin Screw Supercharger and Stage II heads, catback exhaust.

I normally do not drive it due to the fuel consumption and my commute but lately I have had to drive it daily. My past mpg has been 18hwy and 12-13 in town. Right now, I'm getting closer to 11mpg. (I drive like an old lady so I think it should be higher).

I even swapped my heavy 20's for some lighter 18's (Ford Lightning svt rims) and there isn't much difference...

So, my issue is twofold:

1. What can I do to get better mpg?
2. Why does the truck feel gutless? (Factory specs state 260hp and 345 tq-- the SC should add about 100 more hp according to them- it has a pulley for 8lbs of boost only and no intercooler)

I'm thinking I should be close to 400hp but it sure doesn't feel like it. Wondering if there is a tuner that can look into this or if someone can point me in the right direction.

 

[rburch]

How many miles are on it and when is the last time the MAF sensor was cleaned?

 

[toms89]

Hello All:
I joined sometime ago but lost track of the forum...

I have a 2000 Expedition XLT, 5.4L, with a Kenne Bell Twin Screw Supercharger and Stage II heads, catback exhaust.

I normally do not drive it due to the fuel consumption and my commute but lately I have had to drive it daily. My past mpg has been 18hwy and 12-13 in town. Right now, I'm getting closer to 11mpg. (I drive like an old lady so I think it should be higher).

I even swapped my heavy 20's for some lighter 18's (Ford Lightning svt rims) and there isn't much difference...

So, my issue is twofold:

1. What can I do to get better mpg?
2. Why does the truck feel gutless? (Factory specs state 260hp and 345 tq-- the SC should add about 100 more hp according to them- it has a pulley for 8lbs of boost only and no intercooler)

I'm thinking I should be close to 400hp but it sure doesn't feel like it. Wondering if there is a tuner that can look into this or if someone can point me in the right direction.

This is difficult to answer without much more info. I have been tuning my combo myself and starting to get a good grasp on the tuning aspect of it. I learn more each day... .

I assume you have stock compression short block since you made no mention of it. The higher compression combined with no intercooler makes for a temperamental combination in the summer heat. If the intake temps are kept in check it will run strong... if they get excessive the ecu can pull a lot of timing killing power and efficiency negating much of the superchargers benefits. I have the intercooled kit from a lightning with fluidyne heat exchanger. I also have a "Killer chiller" which uses the a/c to cool the fluid even more. My iat temps on a 90+ degree day runs 120+ and can climb under longer periods of boost. Most tuners start pulling timing when the iat reaches 140. The higher it goes the more timing is pulled. With no form of intercooling your iat temps are certainly 140+. When you are not into boost the blower is still recirculating the air via the bypass valve which heats it up.

If you have no intercooler I would highly recommend a water/meth injection kit and have the tune revised for it.

 

[scexy]

Thanks for the quick responses...

She has 102k and the top end was rebuilt at 100k. Everything was cleaned. (Yet I also keep getting the P0401 code--and I did replace the DPFE so I'm sure it's a matter of better cleaning.)

I had wanted to swap to a lightning set up with the I/C but it wasn't in the cards. However, I have been considering some alky/meth injection for it... Sadly my tune was done in SoCal by Stillen and I am not aware of any tuners near to me.

 

[toms89]

The dpfe sensor monitors egr function. I believe the code points to insufficient egr flow so I would check the egr valve and plumbing for carbon deposit buildup.

 

[scexy]

Do you guys know of any tuners nearby me here in KY? Or do you all do your own tuning? I haven't touched the ecm and frankly should probably not be fooling with the tune as it's beyond my capabilities.

I do have a scanproII (I think that's what it's called) that lets me monitor the majority of functions (for MPG purposes)- it reads mal codes and can give you a baseline mpg and so on... Not sure if that is helpful enough.

 

[Big Red Monster]

the dpfe has two hose coming out of it, one hose may be cracked so check that out if you want, thats what was wrong on mine, put on two new hoses and the light went off

 

[toms89]

Do you guys know of any tuners nearby me here in KY? Or do you all do your own tuning? I haven't touched the ecm and frankly should probably not be fooling with the tune as it's beyond my capabilities.

I do have a scanproII (I think that's what it's called) that lets me monitor the majority of functions (for MPG purposes)- it reads mal codes and can give you a baseline mpg and so on... Not sure if that is helpful enough.

I don't know of tuners in your location but there are many good tuners available online. Its not ideal and can take longer but they can be tuned via datalogging. You just need a flash device or "tuner" that supports the software the tuners are using. I have an SCT 3000 because it seems most use their software.

Check out LightningRodder.com and their vender section.
I feel its a good place to search because the lightnings are supercharged and practically all of them have been tuned by some vender.

 

[Stoned06]

I would guess the Summer heat without an intercooler is killing your power.
As far as a tuner in your neck of the woods, I don't know where in KY you are, but MD Motorsports in Alexandria KY (just south of Cincy) worked on my Harley truck and did a very nice job.

 

[scexy]

Thanks to all of you for the good info... I need to double check my dpfe lines. IIRC they were all good. I think it's in the t/b that I need to focus... It's just a royal PITA to mess with this truck. Even lowered, it sits too high and everything is so tight in the engine bay=== well, you guys already know this...

I also checked out MD Motorsports. I couldn't find a web page for them but I did find them list on BBB with an "F" rating due to unresolved complaints....

I have also spent some time on the lightning forum. I have been hesitant to get a flash device as I am not computer literate enough to fool with the programming stuff.... I'm trying to get a friend of mine who tunes WRX's to look at my truck. We'll see... Till then, I'll keep reading and learning.

Thanks again.