mpg drop with reg return..

Nic · Jul 19, 2012

is this supposed to happen? My buddy says his dropped and cant break 17mpg..

windrunner408 · Jul 19, 2012

This doesn't make sense. I would think he probably has a small fuel leak. I know when I had first installed a RR kit, I noticed higher than normal fuel consumption and found I had a leak that once I fixed, everything went right back to where it was before.

Have him drive the vehicle for about 12-15 miles so everything is good and warm/hot and then have him park on a CLEAN piece of asphalt or concrete and look under the vehicle for any fuel drops. I would think it would be small but you should see something if there is a leak.

Just to make sure, is the RR kit the only mod he has done since he last checked his fuel economy??

Strictly Diesel · Jul 19, 2012

Nope, certainly should not. The amount of fuel injected is 100% determined by the capacity of the injector, size of the injector nozzle, injection pressure and injector pulsewidth. Unlike gasoline injectors, the amount of fuel injected should not significantly change based on fuel flow or pressure changes of a regulated return. Obviously, if the stock setup was not properly filling the injectors, there might be some minor change with the updated fuel system...but the statement in bold above still holds true.

Now, if there's an external fuel leak, that's a different story. There could be other issues in the truck causing poor economy as well.

Pizza pig · Jul 19, 2012

tell him to buy a tdi if he's worried about mpg...

and make sure he reads this thread http://powerstrokearmy.com/forums/showthread.php?t=17133

Nic · Jul 19, 2012

no sir, he first did the work, (studs etc) then got a set of brand new injectors, then a FASS 90, blue spring mod, amsoil bypass then RR...Hes in ND right now and recently went through a fuel gelling problem and then got a tank full of water, clogged up the FASS and ruined 4 of 8 injectors..Since then hes replaced all of them, got the problems fixed and installed the RR and got Innovative tunes. He Has the Banks IQ and six gun still hooked up but keeps it in stock when he runs the IDP tunes. He said hes tried everything for economy. He detunes it and runs the Banks in economy and still cant break 17. Ill let him know to check the leak. If he was in a dry place he might have caught it by now but hes constantly in snow and rain.

Nic · Jul 19, 2012

pizza pig said:
tell him to buy a tdi if he's worried about mpg...

and make sure he reads this thread http://powerstrokearmy.com/forums/showthread.php?t=17133

i completely understand this and so does he. But he was getting better economy before and now it has dropped. Hes not the type of person who expects 30mpg out of his truck but he knows what he was getting before and now it has dropped.

oke:

Pizza pig · Jul 19, 2012

hows he calculating it? I wonder if the banks' IQ has dropped

Nic · Jul 19, 2012

pen to paper...ill tell him to chime in. Hes on here but doesnt know i started this thread..

HeavyAssault · Jul 20, 2012

So what was his MPGs before??

jbkingranch · Jul 20, 2012

Howdy fellas. This is my truck Nic is referring to.

No leaks on the truck externally. Truck is not makin oil so I don't believer there is any internal leaks. Just sent a oil sample in for the 15,000 mile mark on my 5w-40 Amsoil. We'll see if the oil is just crap or what here really soon.

Best I ever got was 22.67mpg pen to paper. Did a leveling kit and some 305/55R20's and dropped me around 17mpg. This was going down the same stretch of highway on I-45 from Dallas to Houston. Dieseled up at the same place and ran Ford cetane booster in every tank. All 8 of the injectors that got replaced were on the right side. I was using my truck for the company I was working for. Got a ton of water one time and the second time fuel gelled up. Both time my boss bought me 4 remanned units from Ford. I did the work. #7 injector was the only one that crapped on me but was told its best to do all of them on that side.

Second time I did injectors installed the RR and can't break 15.7. That's with the IDP X-street. Can't get out of the 14mpg range with there Economy tune or the Banks Economy tune.

jbkingranch · Jul 20, 2012

The injectors on the left side are a year and a half old with around 30,000 miles and the ones on the right are 6 months with around 15,000. Could that cause a imbalance or make any kind of issue.

There are no fuel leaks. Keep it washed pretty good under the hood and constantly check on it.

windrunner408 · Jul 20, 2012

Man 15000 miles on a single oil change is a LONG way to go. I'm curious to see what your oil analysis says. I run Amsoil 5w-40 and Archoil AR9100 and I still change it out every 5-6k miles but I also don't do oil analysis.

For the life of me, I can't figure out why you would drop fuel economy. The only thing I can think of is that there is something wrong with your injectors that is causing this poor performance. You could do contribution test but I dont think it will tell you a whole lot. I hate to say it but I recommend just pulling all 8 injectors and sending them to Jesse Warren and have him go through them. If there is a problem with them, he'll find it. I know you bought them as brand new remans but even Ford Motorcraft remans have been known to be junk out of the box and right now arent being blamed as the culprit to your poor fuel economy but this is where I think your problem is. Either way I hope you can get this figured out. If you dont want to do this, I recommend giving Vivian at Quick Tricks a call and getting her Looney Wild tune as I have heard the highest fuel economy claims with this tune over Eric's tunes. JMO and hope this helps.

Nic · Jul 20, 2012

^^ good info i couldnt figure it out either. He has the oil bypass system thats why he went 15k. Its all highway miles and he doesnt constanly stand in the throttle and blow smoke all over the place so 15k should be on the low end of miles. Amsoil CLAIMS you can go 50k and 25k on the 2 micron filter but i couldnt imagine anybody doing that...especially on a tuned vehicle or one that tows.

jbkingranch · Jul 20, 2012

I'm changing my full flow filter ever 3500. Still haven't changed the bypass. I took my sample off the bypass line returning to the engine. Still has a lot of flow and the oil looks better now then when I was doing 5,000 mile oil changes with 15w-40 Amsoil and didn't have the bypass. Amsoil recommend doing a sample every 30,000 but I'm not pushing out that much without knowing what's in the oil.

Non the less the mileage has not changed since raking the miles up on the oil.

windrunner408 · Jul 20, 2012

Nic said:
^^ good info i couldnt figure it out either. He has the oil bypass system thats why he went 15k. Its all highway miles and he doesnt constanly stand in the throttle and blow smoke all over the place so 15k should be on the low end of miles. Amsoil CLAIMS you can go 50k and 25k on the 2 micron filter but i couldnt imagine anybody doing that...especially on a tuned vehicle or one that tows.

I know what they claim and I would totally be ok going 15k if the oil in these motors wasn't worked so hard by the HPOP. That's the only reason I stick with a shorter change interval. I would only go farther with the oil analysis and if he is doing that then he should be good to go.

jbkingranch said:
I'm changing my full flow filter ever 3500. Still haven't changed the bypass. I took my sample off the bypass line returning to the engine. Still has a lot of flow and the oil looks better now then when I was doing 5,000 mile oil changes with 15w-40 Amsoil and didn't have the bypass. Amsoil recommend doing a sample every 30,000 but I'm not pushing out that much without knowing what's in the oil.

Non the less the mileage has not changed since raking the miles up on the oil.

Well the filter change interval makes me feel better I guess. I presumed you had the bypass filter kit in.

jbkingranch · Jul 20, 2012

I agree about oil working harder. I do have the bypass on right now and have been running this system for 2 years. Only change with the oil is went from the 15W-40 to 5w-40 after moving to North Dakota. With the 15w and no RR the truck would spit and sputter at 30 degrees. Would not crank below that. With the 5w and the RR she'll bust off at -15. No ****!!!

I'll see if I can get to the stealership soon and have a power balance run. If anything is wrong injector wise I'll send them to Warren and have some 190's built.

Now as far as fuel pressure been told don't go over 65psi. I'm running it at 60psi right now. What's your thoughts on that.

windrunner408 · Jul 20, 2012

Yea that 5w-40 is GREAT oil for sure. That is awesome that it'll run at -15F. I don't ever see temps that cold but I still use 5w-40 even in this 100F+ heat that I am in down here in TN.

Yea running your fuel pressure between 60-65psi is just fine. There isn't any need to go over 65psi. IMO, your fuel system will keep up and maintain fuel pressure above 45psi at WOT or it wont, regardless of where you set your fuel pressure. I also think you need over 40psi to keep your injectors from cavitating and causing wear. JMOs though.

Nic · Jul 20, 2012

now to minitor this you would have to have to correct PIDs in your programmer or via analog gauge..i have the TSX and dont think i can monitor fuel pressure...He has the IQ and im almost positive that it does..right Jesse?

09stroker · Jul 20, 2012

Low FICM voltage?

windrunner408 · Jul 20, 2012

There is no sensor that the ECU sees that will allow Fuel Pressure to be pulled through the OBDII port. Fuel Pressure is read via either an analog gauge and/or an add on to a monitoring device. To my knowledge only the Edge Insight CS/CTS and Dashboss can be set up to add things like fuel pressure, oil pressure, and just about any 0-100psi pressure parameter that you desire to read. Also, I dont think the IQ can be expanded at all to read pressure parameters. Hope this helps.