Go Back   Ford Truck Enthusiasts Forums > Performance, Engines & Troubleshooting > Modular V10 (6.8l)
Sign in using an external account
Register Forgot Password?


Modular V10 (6.8l) SPONSORED BY:

Welcome to Ford-Trucks Forums!
Welcome to Ford-Trucks.com.

You are currently viewing our forums as a guest, which gives you limited access to view most discussions and access our other features. By joining our community you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is fast, simple and absolutely free so please, join the Ford-Trucks Forums community today!





 
Reply
 
 
 
 
LinkBack Thread Tools Search this Thread
  #1  
Old 11-06-2013, 10:57 AM
jmo1112 jmo1112 is offline
Junior User
 
Join Date: Mar 2011
Posts: 51
jmo1112 is starting off with a positive reputation.
Poor gas mileage after tune up

Hey guys. I posted this in the E-van forum, but one of them recommended I post here, as well. So here's the issue:
I have a 2004 E350 V10 with 240k miles on it. I had a terrible miss, which became multiple cylinder misfires. I just replaced all 10 spark plugs with Motorcraft SP-479's, and all 10 COP's with cheapos from eBay (yes, I know the gamble there. Used them on my F150 and had great success, so I tried again with the van). Turns out 3 of the new cheapos were bad, so I put the original Motorcraft COP's back in those 3 spots. So no misses and no CEL now. However, my gas mileage is horrendous. Even worse than when I had all the misfires. Any ideas what could be going on?

Thanks for any help and/or ideas.
Reply With Quote
  #2  
Old 11-06-2013, 12:08 PM
rvpuller's Avatar
rvpuller rvpuller is offline
Moderator
 
Join Date: May 2004
Location: Home Base Nebraska
Posts: 2,340
rvpuller has a very good reputation on FTE.rvpuller has a very good reputation on FTE.rvpuller has a very good reputation on FTE.rvpuller has a very good reputation on FTE.
I have never worked on a V10 on a van but the first thing I would do is check all the vacuum lines and the hose and fittings that come left valve cover to the air inlet tube not the PCV valve, the side may be different on a van. That tube is after the MAF sensor it can throw things off if it's sucking air.

Denny
__________________
Moderator 6.2 & V10 Forum
2013 F350 Lariat SC DRW 2WD 6.2 4.30 Gears Air Lifts 50 Aux tank
2003 HH Premier 35 FKTG
Retired 2000 F350 Lariat SC DRW V10 4.30 Gears BrakeSmart
Air Lifts 4X2
http://www.ford-trucks.com/guidelines.html
Reply With Quote
  #3  
Old 11-07-2013, 08:05 AM
Krewat's Avatar
Krewat Krewat is offline
Super Moderator
 
Join Date: Jul 2002
Location: Long Island USA
Posts: 34,460
Krewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputation
I think your van has the same air box as the F-series. Check the rubber plug on the bottom of the MAF housing where the wires go through. If that's not in place, it'll allow a small amount of air to get past the MAF causing the engine to run lean.

I know, LEAN makes it use more gas? Yes - because of the lack of power, you need to lean into the gas pedal more, causing more air (and fuel) to enter the engine. But still lean, so lack of power, and yet, more gas overall.

Same theory applies to any other vacuum leak.
__________________
- art k. - Moderator for the Superduty, V10, 6.2L and FE forums
'13 Taurus SHO 3.5L Ecoboost w/Perf Pkg
'01 F250SD SC SB XLT V10 4x4 Volant CAI Hedman headers 5-star custom tunes on SCT X3
'97 Cougar XR7 30th Anniv Edition 4.6L
'74 F250 Highboy FE390 deceased!
I've been wrong before, I'll be wrong again. Just wait and see. ®
Reply With Quote
  #4  
Old 01-07-2014, 12:14 AM
jmo1112 jmo1112 is offline
Junior User
 
Join Date: Mar 2011
Posts: 51
jmo1112 is starting off with a positive reputation.
Hey, so this is a super late response, but I haven't really been driving much my van lately. I did use it this weekend, and after checking all the hoses and fittings, everything seems on tight, but bad gas mileage still remains. That said, I am smelling gas while the van is running. I've taken the dog house back off, as well as looked through the hood, and I can't SEE any gas, but I can certainly smell it. Any idea what I should be looking for, or what I should check first in trying to diagnose this?

Thanks.
Reply With Quote
  #5  
Old 01-07-2014, 12:42 PM
truckfella's Avatar
truckfella truckfella is online now
Senior User
 
Join Date: Jul 2005
Posts: 425
truckfella is gaining momentum as a positive member of FTE.
You say your mileage is horrendous. Can you be more specific on what it went from/to? Just curious.
__________________
2003 F350 V10 CC/LB Lariat 4x4, Auto w/ 3.73 axles, 285/75/16 tires. 90k miles. Software by 5-star.
Arctic Fox 811 slide-in camper
SW Idaho
Reply With Quote
  #6  
Old 02-18-2014, 03:47 PM
jmo1112 jmo1112 is offline
Junior User
 
Join Date: Mar 2011
Posts: 51
jmo1112 is starting off with a positive reputation.
Hi there. Unfortunately my lack of timely posting does not mean I've fixed the problem.

Under normal conditions, I was able to get between 350-390 miles to a full tank of gas. Mostly highway driving, but some city. In its current state, I get about 250 miles to a full tank of gas. Literally at least 100 miles difference. And it still smells like gas in the cab every time I crank the van.

Got any ideas?

Is it possible I don't have a spark plug seated correctly or something? I mean, it's not running poorly. No misses, and CEL. It's just eating gas like crazy, and smelling like gas.

Sorry again for my late response on this and bringing up old threads. My problems just haven't been solved yet, and it's been to freaking cold to go outside and try to fix things.
Reply With Quote
  #7  
Old 02-18-2014, 11:09 PM
eberlestock's Avatar
eberlestock eberlestock is offline
Senior User
 
Join Date: Jul 2012
Location: prince george, bc canada
Posts: 134
eberlestock is starting off with a positive reputation.
I had the plugs changed on my F250 and noticed the same thing. The truck idles smoother but is using more gas. I am going to check the plug that somebody mentioned on the maf.
__________________
Better a sister in a *****house than a brother in a chev
Reply With Quote
  #8  
Old 02-19-2014, 02:21 AM
Bently_Coop's Avatar
Bently_Coop Bently_Coop is offline
Posting Guru
 
Join Date: Mar 2013
Posts: 1,343
Bently_Coop has much to be proud ofBently_Coop has much to be proud ofBently_Coop has much to be proud ofBently_Coop has much to be proud ofBently_Coop has much to be proud ofBently_Coop has much to be proud ofBently_Coop has much to be proud ofBently_Coop has much to be proud of
Do you have any check engine light codes or pending codes? Have you changed the fuel filter? Check under the throttle body for vaccuum leaks as well.

I am a big fan on using OEM parts to tune up my truck and cars.
__________________
99 F250 CCSB V10 - 4"MBRP cat back, SPD y pipe, K&N Drop in, zoo dad, Powerslot cryo rotors up front, hawk pads all 4 corners, weathertech visors, husky liners, 2008 Complete back end, Bilstein 5100 up front and pro comps in rear, Bestop EZ roll. More to come....
Reply With Quote
  #9  
Old 02-19-2014, 02:03 PM
fordboy2 fordboy2 is offline
Posting Guru
 
Join Date: Dec 2005
Location: freeland, mi
Posts: 1,160
fordboy2 is gaining momentum as a positive member of FTE.
I lknow I have read about cleaning the MAF, could this contribute to his issue if it is dirty?
__________________
2005 ccsb 6.0 sct livewire 9600, sinister egr delete, turbo back 4 inch exhaust, k&n fipk, 295/55/20 with moto metal wheels

99 f350 CCLB lariat 6.8 4wd No Cat Flow Master Muffler.
Reply With Quote
  #10  
Old 03-10-2014, 05:48 PM
jmo1112 jmo1112 is offline
Junior User
 
Join Date: Mar 2011
Posts: 51
jmo1112 is starting off with a positive reputation.
Fordboy, I did try cleaning the MAF. It did not seem to help.

Bently, I don't have any CEL codes or anything. I, too, like to use OEM products. My budget, however, doesn't allow for such things. I also changed the fuel filter probably 30k miles or so ago.

Because of the rather strong gas smell, it was brought up to me that I must have a leak, as I shouldn't be able to smell gas with the engine running. I was told to check for a leaky fuel injector. I don't have a bad enough leak that anything is hitting the ground underneath the van, but when looking at the injectors, all of them are bone dry except number 1. It has a little pool of what I assume is gas inside the lip at the top of the injector. Could that be my issue?!

I do not have experience at replacing an injector. I've seen there a several videos on youtube and such on how to do it. However, I'm not sure what to expect when lifting the fuel rail. Is it difficult to get off? What steps do I need to do besides removing the bolts and disconnecting the fuel lines (the lines, of which I don't know the location)?

Thanks for your help and ideas on this so far and moving forward.
Reply With Quote
  #11  
Old 03-11-2014, 10:17 AM
jmo1112 jmo1112 is offline
Junior User
 
Join Date: Mar 2011
Posts: 51
jmo1112 is starting off with a positive reputation.
Okay I did a bunch of research last night, and I'm far less worried about removing the fuel rail than I was yesterday. Here's my next question.

If I have a leaking fuel injector, is it just the O-ring that is failing, or do I need to replace the entire injector? The van seems to be running fine. I don't have a miss. Clearly, that's a large price difference in parts, and I don't want to spend $100 for an injector when I could fix the problem by spending about $8 for O-rings.
Reply With Quote
  #12  
Old 03-11-2014, 10:53 AM
ForKyleigh ForKyleigh is offline
New User
 
Join Date: Mar 2014
Posts: 8
ForKyleigh is starting off with a positive reputation.
Did you removed the fuel rail when you changed out the coils? If you didn't, I wouldn't expect that something went bad during the coil/plug change. There are four bolts, two on the sides of the intake manifold. There is also one on the back of the intake manifold. (should be the same as my f250) The one on the back of the manifold should be easy to access from the doghouse.

You should be able to inspect the O ring and determine if it is good or bad. Is it split, torn, etc?

Have you scanned the engine for codes? You should see if there are any "pending" codes. Pending codes will not make the CEL light go on.

You could try to just turn the key forward to the run position a few times to pressurize the system. Then sniff around. That way the engine is not running. You may need to re pressurize it a few times.

Otherwise the should be a valve on the passenger side of the fuel rail. Borrow/rent a fuel pressure gauge. Hook it up to the valve, and pressurize the system. It shouldn't fall. Yours probably will, but how fast? That will give you an idea of how bad it is.

Do you sniff the exhaust? Notice any difference? Did you plug your idle air control valve back in? It is just behind the throttle body.

Lots of ideas for you.... I am still a little new to the v10. But, no stranger to motors. I just pulled the top half of the v10 apart to find a coolant leak. I replaced all the same items you did while it was apart.
Reply With Quote
  #13  
Old 03-11-2014, 03:27 PM
jmo1112 jmo1112 is offline
Junior User
 
Join Date: Mar 2011
Posts: 51
jmo1112 is starting off with a positive reputation.
Those are lots of good ideas. I didn't remove the fuel rail when doing the coils/plugs, but it's possible that I put some undo pressure on the rail when reaching for bolts and plugs and such.

I haven't taken the rail out yet, so I haven't inspected the O-ring yet.

I don't have a diagnostics tool, but will the Autozone free check tell you pending codes? That is something I can certainly get done today.

I will certainly try a bunch of this stuff, hopefully today, and maybe get a little closer to a diagnosis.
Reply With Quote
  #14  
Old 03-11-2014, 10:05 PM
Bently_Coop's Avatar
Bently_Coop Bently_Coop is offline
Posting Guru
 
Join Date: Mar 2013
Posts: 1,343
Bently_Coop has much to be proud ofBently_Coop has much to be proud ofBently_Coop has much to be proud ofBently_Coop has much to be proud ofBently_Coop has much to be proud ofBently_Coop has much to be proud ofBently_Coop has much to be proud ofBently_Coop has much to be proud of
I dont think the Autozone/ oreilly scanners will show pending codes. However the local dealership can do a diagnostic check for you. Of course there is a fee. I would call and check around the area. Unless you know someone with auto engenuity or a snap on scanner that is able to show live data.
__________________
99 F250 CCSB V10 - 4"MBRP cat back, SPD y pipe, K&N Drop in, zoo dad, Powerslot cryo rotors up front, hawk pads all 4 corners, weathertech visors, husky liners, 2008 Complete back end, Bilstein 5100 up front and pro comps in rear, Bestop EZ roll. More to come....
Reply With Quote
  #15  
Old 03-21-2014, 01:23 AM
jmo1112 jmo1112 is offline
Junior User
 
Join Date: Mar 2011
Posts: 51
jmo1112 is starting off with a positive reputation.
This might be the slowest repair I've ever attempted...

So I was digging in to this today to try and repair this injector issue, and I think I may have found a bigger problem. Would these pics be an indication of a cracked fuel rail? It is definitely wet to the touch, and smells like gas, but I can't see gas coming out of there when I turn the key on. I can, however see it running down the injector.

None of the other injector spots look like this. Also, the connector that goes into the injector (not pictured) is totally discolored and basically black. None of the other connectors look like this.

If it is a cracked a fuel rail, is it just as straight forward as removing this one and replacing it with a new one? After a quick Google and Rock Auto search, I can't seem to find a fuel rail. Am I just calling it the wrong thing?


Click the image to open in full size.

Click the image to open in full size.

Click the image to open in full size.
Reply With Quote
Old 03-21-2014, 01:23 AM
 
 
 
Reply

Go Back   Ford Truck Enthusiasts Forums > Performance, Engines & Troubleshooting > Modular V10 (6.8l)

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
HELP!!!..EX MISSING ON CYLINDER 1 Jkelley Excursion - King of SUVs 80 11-25-2013 11:50 AM
Poor gas mileage after new plugs and COP's jmo1112 1968-2013 Full Size Vans 2 11-06-2013 10:54 AM
infamous cop problem ole_smokey_88 1997 - 2003 F150 3 01-29-2013 02:15 PM
Just changed plugs & COP's on F250 Utah F250 1997 - 2003 F150 3 02-13-2011 10:46 AM
slight stuttering on acceleration/ COPs? kynnhoj 1968-2013 Full Size Vans 0 12-05-2006 06:45 PM



All times are GMT -5. The time now is 01:10 AM.


Powered by vBulletin® Version 3.8.7 AC1
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Advertising - Terms of Use - Privacy Statement - Jobs
This forum is owned and operated by Internet Brands, Inc., a Delaware corporation. It is not authorized or endorsed by the Ford Motor Company and is not affiliated with the Ford Motor Company or its related companies in any way. Ford® is a registered trademark of the Ford Motor Company.

vbulletin Admin Backup