mpg keeps getting worse after fuel efficiency mods??HELP!!

[sms8921]

Changed the timing back. We will see if that does anything. I was probing around my headers and I noticed that on the passenger side the two middle exhaust headers are just warm to the touch will running the front was very hot and I couldnt feel the rear. Is this an idication of something? Truck smokes a little more now that I advanced timing back but even heavy in the throttle it is a grey haze coming out of the exhaust not black.....? Also if I decide to get new ip and injectors I will go with the bb's but who should I buy the pump from and what all do I need to buy to do a complete overhaul of that system?

 

[riotwarrior]

Get a set of BB's from Mel (Agnem) or Type4 (Russ) here...Mel has Moose pumps available...very nice!

 

['94IDITurbo7.3]

Well buying new ip and injectors doesnt justify why the mpg went down when I put the mods on to gain more mpg. I dont think both my ip and injectors would go bad in one tank full of fuel would they?

that is pretty much how my injectors died. one day all was good. next day, crap ton of blue/white smoke, sounded like a rod was gonna go threw the block. turns out i had 4 bad injectors. replaced all 8, that showed how weak the IP was, replaced that and have been good for almost two years now.

 

[RLDSL]

. I was probing around my headers and I noticed that on the passenger side the two middle exhaust headers are just warm to the touch will running the front was very hot and I couldnt feel the rear. Is this an idication of something?

Does sound a bit like the injectors are firing a bit irregularly, if normal, the front one should be the coolest, then the rest should be fairly close but getting slightly hotter along the way back as you are adding cylinders along the way ( if you use a non contact temp probe and measure right where the manifold meets the head, they should all be about the same with the varryances showing at the outside of the manifold )

 

[PwrSmoke]

Some good advice given so far. I was amazed at how much better my truck ran after a proper timing job. Actually, it was set to near the correct stock spec but when Mel set it to 9.5 (about 2.5 advanced of what it was, IIRC), I could feel a difference. It smokes more at the same fuel setting and definitely feel snappier. Thus far, my mpg is a few ticks ahead of what it was but I have a lot of averaging to do yet to see about how much the mpg improved (if at all). And that brings me to my point... methodology:

Did you take your last mpg before the change and then compare it to the latest? One mpg calc compared to another? I would submit that's not enough info for a condemnation... or a proclamation of victory if it had gone that way. There are too many variables. Maybe more cold starts on one tank vs the other. More traffic. Different routes driven. Changes in ambient temperature (cooler weather usually drops the mpg). More spirited drive on one tank vs the other... and the list of variables go on and on. The only way you can really compare is by averaging a large number of mpg calcs in both conditions or by running specific tests where you equalize all the variables. I recently tested some products for mpg improvements on a particular course I had mapped out previously. I test drove the course first and took notes on the route so I could drive the same way as much as possible on two test loops. I even went to the trouble to make sure the engine, trans and differential oil temps at the start of each tests were these same, as well tire temps and making sure ambient temps were the same for each loop. There was a lot more to it even than that, but I won't bore you with it. In the end I was pretty confident in having equalized all the variables but the products being tested.

Also, like was said above, most of the things you upgraded won't necessarily result in a noticeable increase in mileage. They are often touted as such but when you get into the real science, any gains are pretty small if at all noticeable. Power, lower EGTs... certainly. MPG, not so much.

 

[sms8921]

Well I think I figured out why I started getting worse milage. My torque converter was starting to go. It would go into limp mode overy once and a while and it finally started to slip really bad today. Gonna cost 2400.00 for a new built tranny with a billet converter and shift kit and all the goodies. Hopefully it will feel like a different truck. I pull a 3000lb trailer and it always felt like the trailer was really heavy and the truck struggled. New converter and internals hopefully will help with that!

 

[riotwarrior]

Well I think I figured out why I started getting worse milage. My torque converter was starting to go. It would go into limp mode overy once and a while and it finally started to slip really bad today. Gonna cost 2400.00 for a new built tranny with a billet converter and shift kit and all the goodies. Hopefully it will feel like a different truck. I pull a 3000lb trailer and it always felt like the trailer was really heavy and the truck struggled. New converter and internals hopefully will help with that!

Makes sense...makes total sense....

 

[Wyreth]

Well I think I figured out why I started getting worse milage. My torque converter was starting to go. It would go into limp mode overy once and a while and it finally started to slip really bad today. Gonna cost 2400.00 for a new built tranny with a billet converter and shift kit and all the goodies. Hopefully it will feel like a different truck. I pull a 3000lb trailer and it always felt like the trailer was really heavy and the truck struggled. New converter and internals hopefully will help with that!

Fix the transmission issues, get it properly timed, and I think you will be amazed at the difference. My N/A 6.9 simply doesnt notice a mere 3k trailer.

 

[PwrSmoke]

Well I think I figured out why I started getting worse milage. My torque converter was starting to go. It would go into limp mode overy once and a while and it finally started to slip really bad today. Gonna cost 2400.00 for a new built tranny with a billet converter and shift kit and all the goodies. Hopefully it will feel like a different truck. I pull a 3000lb trailer and it always felt like the trailer was really heavy and the truck struggled. New converter and internals hopefully will help with that!

OUCH! That stings! Your truck will be better for it... not your wallet though.

 

[rpm427]

These trucks transmissions need something done to them as they kinda slip between gears stock.Shift kit is the best bang for the buck or a Trans Command before they go out!

 

[sms8921]

I think the shift kit he is installing is called a tugger or something idk. The billet converter is getting custom work done to it though. And the tranny guy has built alot of these e4od's before so hopefully this will help the problem. I am really excited to get it back though I can tell you that much.

 

[SparkandFire]

Sorry to hear about your transmission troubles!

Reminds me that I need to service and install a shift kit in my van before I burn that transmission up driving around the hills where I live...

On the subject of timing, some while ago I posted a bunch of information I had found from the Navy doing research on how injection timing affects big ship diesels. They had done some pretty good studies on why timing affects fuel usage and performance so much. The little bit of it I managed to get to stick in my brain was the relationship between fuel injection timing and flame temperature and expanding gas dwell time.

Think of it this way. The sooner fuel is injected before the piston arrives at top dead center, the more time the fuel has to burn, resulting in a higher flame temperature (higher temperature corresponds to more energy converted from the fuel into work.) This is GOOD for efficiency but BAD for emissions, as NOx is created by those high flame temps. According to the study, the higher net output from the engine with the timing advanced lowered fuel consumption, since the engine was releasing more energy from the fuel, less fuel was needed to maintain speed at load.

I think this is why the factory timing was somewhat retarded on our IDI's when they left the factory. NOx formation is one of the biggest emission sources from diesels in general. Ford/IH had to limit NOx to some arbitrary level set by the government. Diesel fuel today isn't at all what it was thirty years ago, so between conservative factory timing settings and lower cetane fuel available, I think even if you were to bring a brand new IDI truck back from the past with a time machine, it's performance would most certainly disappoint...

 

[sms8921]

Ok new tranny in her now. I can actually feel the converter lock. The trans seems very stout. The only code that wont dissapear is 23, tps out of range. I have my tps set at 1.3 at idle and 3.8 wot. It shifts at basically the ideal times when towing and OD light isnt blinking. How do I fix the code? If I dont fix it will it hurt the new tranny? Also I noticed when I really get into the throttle the new shift kit shifts differnet, but when it does shift from 1st to 2nd there is slight turbo chatter from unspooling. I think the cowl made it noticable cause I have a loud turbo whistle in the cab now too. Does anyone elses turbo do that on these old trucks?

 

['94IDITurbo7.3]

My turbo screams like a **** when it down spools like you describe.

the idle setting on the TPS is a little high. i think it shouldn't be higher than 1.2VDC at idle. code 23 is just not holding the throttle @ WOT during code scan.

 

[icanfixall]

Maybe disconnecting both batteries will clear the code. The tps voltage is set from .96 to 1.2 volts. You could drop the voltage setting a bit. Or replace the tps if its been on the truck for more than 50,000 miles. They do waer out. They are a potenciameter type switch. That means there is a slidding finger running across a lot of wires making the voltage signal. Same thing as a fuel tank sender or a heater reostat.