Engine Work = Bad MPG
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Engine Work = Bad MPG
So I spent all last weekend doing some work to my truck. Have 160k on my '99 PSD & I did a fuel bowl rebuild, IPR tear apart & rebuild, all new glowplugs & a Stancor GPR, pulled my injectors & cleaned them with some new Allient o-rings, checked over the UVCH & did the 50 cent mod, re-torque my rocker arm bolts & injector bolts, added a HPX & an FRX & did just a general clean & inspect of everything under the hood. She starts & runs 10 times better then before, but I've noticed my fuel mileage has gone down from around 12-13 to about 10-11. Was kinda hopeing it would go the other way lol. Does this seem right? Any ideas? Thanks guys!
Hotshot
Joined: Jan 2011
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From: Puget Sound
Yup! Your're getting that from the overhead. Any time you mess with the fuel system, the accuracy of the overhead changes. Mine looked depressing when I did the hutch mod, but the overhead just got more accurate and my hand-calculated MPG was unchanged... even though the truck sounded better.
Post Fiend
Joined: May 2009
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From: Pea Ridge, AR
Seems pretty quick to assume mileage has dropped unless you have put a lot of miles on it.
But the first thing that comes to mind with what you have done would be boost leaks. Making sure you got the spyder lined back up and sealed properly, all boots back on and tightened well not leaking, etc.
But the first thing that comes to mind with what you have done would be boost leaks. Making sure you got the spyder lined back up and sealed properly, all boots back on and tightened well not leaking, etc.
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Seems pretty quick to assume mileage has dropped unless you have put a lot of miles on it.
But the first thing that comes to mind with what you have done would be boost leaks. Making sure you got the spyder lined back up and sealed properly, all boots back on and tightened well not leaking, etc.
But the first thing that comes to mind with what you have done would be boost leaks. Making sure you got the spyder lined back up and sealed properly, all boots back on and tightened well not leaking, etc.
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Yup! Your're getting that from the overhead. Any time you mess with the fuel system, the accuracy of the overhead changes. Mine looked depressing when I did the hutch mod, but the overhead just got more accurate and my hand-calculated MPG was unchanged... even though the truck sounded better.
Post Fiend
Joined: Nov 2007
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From: Payson, AZ
Besides what Al mentioned make sure all sensors are plugged back up. EBP, EOT, MAP (including hose to MAP), MIAT (Manifold Intake Air Temp in base of spider) and AIT (Air Intake Temp in filter box). It would be nice to hook it to a scanner and check for any codes.
Also, if you overtighten the plenum boots you can easily distort the plenum tubes and cause a boost leak.
Also, if you overtighten the plenum boots you can easily distort the plenum tubes and cause a boost leak.
Hotshot
Joined: Jan 2011
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From: Puget Sound
As for the FRx, it's excellent... if you did the tank mods. If not, you could be sucking air through the quick disconnects, pumping it to the heads, the FRx is sending all the air directly back the mixing chamber, to be pulled up by the pump and mixed with more air from the QDs. Before the FRx, the air would just go out through the injectors and be gone. Perhaps you'd like to know how I arrived at this conclusion... I have the tee-shirt.
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OK... that's new intel. 290 on a tank is not good... is it blowing coal if you get on it?
As for the FRx, it's excellent... if you did the tank mods. If not, you could be sucking air through the quick disconnects, pumping it to the heads, the FRx is sending all the air directly back the mixing chamber, to be pulled up by the pump and mixed with more air from the QDs. Before the FRx, the air would just go out through the injectors and be gone. Perhaps you'd like to know how I arrived at this conclusion... I have the tee-shirt.
As for the FRx, it's excellent... if you did the tank mods. If not, you could be sucking air through the quick disconnects, pumping it to the heads, the FRx is sending all the air directly back the mixing chamber, to be pulled up by the pump and mixed with more air from the QDs. Before the FRx, the air would just go out through the injectors and be gone. Perhaps you'd like to know how I arrived at this conclusion... I have the tee-shirt.
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Post Fiend
Joined: Nov 2007
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From: Payson, AZ
The biggest benefit of the FRx is to eliminate the dead head fuel rail at the back of the driver side head. #6 fires right before #8 and with that dead head fuel rail #8 doesn't always get the proper amount of fuel. With the FRx there is a continual flow of fuel to #8 so it gets it's proper supply. If air is introduced to the fuel system the FRx doesn't really eliminate it but will help it flow through and not get captured at the end of a dead head fuel rail.
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