Topic: gained 2mpg with change

[Bikerjr1]

Over the last tank of fuel I gained a hair over 2mpg.  It went from a dismal 11-13mpg to 15.3mpg.  I made a couple of changes to the 2.5L.  First I changed the fuel regulator to a higher pressure one.  See the long post on this.  I went with a Standard PR211 aftermarket that is in the list.  It installed just like stock.  I already had the 4.0l throttle body w/ spacer and Type III Ford injectors installed, now they work like they should.  I also changed the intake air cleaner back to the stock type one with a Fram element inside.  The one I had was an aftermarket open cone style with the aluminum tube.  I reset the computer so it is still learning some I think.  My YJ seems to have more power in the 2000-3000rpm range.  This is where 60-65mph hit depending on either 4th or 5th gear.  I had also changed the fan to a "quality not cheap" flex fan.  This I'm still debating on keeping or going back to a fan clutch.  I do know that on certain stretches of county roads that I usually had to down shift into 4th I can run in 5th gear.  It still won't handle a head wind and a slight hill at the same time but It is better than it was.  All in all these changes were worth gaining 2mpg. 
JR

[sharpxmen]

you know that's a 50 psi FPR - it's quite high compared to stock 39psi

unless you have some fuel pump problems should be blowing black smoke at wot at that pressure - did you put a gauge on it to see what is the actual pressure at? i'm thinking could be lower but that's what is listed at on Standard's website http://www.standardbrand.com/Online%20Catalogs-eCatalog/Content.aspx click on part number, type in PR211 and select attributes - the one that is stock replacement is PR210 and pressure is listed at 39psi

[chardrc]

also changed the fan to a "quality not cheap" flex fan.  This I'm still debating on keeping or going back to a fan clutch. 
JR

i wouldn't mess around with a flex fan "quality" or cheep ive heard to many story's,1st hand, of them falling apart and ripping people apart. I'd stick with the clutch fan or go electric with controller.

nice job getting 2 extra mpg 

[Bikerjr1]

I'll try and get a guage on it in the next couple of days.  No black smoke, I did check the readings after I installed the injectors with the old regulator and it was in spec.  The PR211 is one of the ones on the list that was posted originally on Jeepforum by user "coas" I think.  It is linked to in the regulator post.  I have read that actual presure is anywhere from 46-50 depending on who's guage.  Anyhow it seems to be working fine.  I did find a line that was leaking at the fuel filter after putting on the new regulator.  I'll post what reading I get at the rail.
JR

[sharpxmen]

the list was for mechanically compatible FPRs - some were different pressure than stock. the 50psi was based on the manufacturer's specs so that's what your reading on the gauge should be give or take 1 psi (at idle with the vac port disconnected).

[Eucalypta]

the list was for mechanically compatible FPRs - some were different pressure than stock. the 50psi was based on the manufacturer's specs so that's what your reading on the gauge should be give or take 1 psi (at idle with the vac port disconnected).

Does anyone know what the max pressure of the stock pump is and at what pressure the stock pumpwill shutdown (and possibly die)?

[turbojeep95]

Following your thread. I want to do this but I'm not sure what fpr I need. I have a 4.0 tb with spacer, cold air intake, banks header, a "very high flow" cat, and a flowmaster. I'd like to get one of the adjustable ones but I don't feel very confident with playing around with it. Let us know how yours turns out.

[sharpxmen]

Does anyone know what the max pressure of the stock pump is and at what pressure the stock pumpwill shutdown (and possibly die)?

i can't remember if I read this somewhere or heard it somewhere but i think is 100 or 110 psi max at 0 flow (max head of the pump) - can't  bet my money on it but somehow it's in my memory

[Bounty Hunter]

Following your thread. I want to do this but I'm not sure what fpr I need. I have a 4.0 tb with spacer, cold air intake, banks header, a "very high flow" cat, and a flowmaster. I'd like to get one of the adjustable ones but I don't feel very confident with playing around with it. Let us know how yours turns out.

Your best bet is one of Sharpxmen's adjustable FPR's and an A/F ratio gauge of some sort.

[turbojeep95]

I have a air fuel gauge ( not a wideband) hooked up.  Whenever i mash the gas from a start it falters and goes lean until a few seconds goes by, then it goes to rich. It would almost die out until I put on my 19lb injectors which helped out.

[Bikerjr1]

I just put the guage in it and here are the numbers.  At normal idle, engine warm, it shows 48#s. At idle with vac line disconnected it shows 54/55#s.  When I first crank it up the exhaust smell a little rich but this stops once the engine warms up.  I filled up last night and the numbers were 140 miles on 9 gallons even.  15.5 mpg.  I will see about getting a air/fuel gauge in the future and see what it says.  I'll run it some more and see how it goes.
JR

[sharpxmen]

I just put the guage in it and here are the numbers.  At normal idle, engine warm, it shows 48#s. At idle with vac line disconnected it shows 54/55#s.  When I first crank it up the exhaust smell a little rich but this stops once the engine warms up.  I filled up last night and the numbers were 140 miles on 9 gallons even.  15.5 mpg.  I will see about getting a air/fuel gauge in the future and see what it says.  I'll run it some more and see how it goes.
JR

that's way too much, something else is going on there
1. that FPR should have 50psi with the vac disconnected, so it's either that your return is blocked (i had the same problem at some point) or that gauge is way off.

2. at that pressure your injectors are equivalent to 20.7lb/hr from the stock 17.4lb/hr, that is 18.75% more fuel - if everything else was working the way is supposed to you'd be with your AFR in the area of 11 at wot, that is way rich - so if you measure your AFR and is over 13 or close then you must have something else that is not giving the right information to the PCM (like MAP sensor for example).

otherwise i can't see how you're getting those results.

[Bikerjr1]

I'll check the return line.  The FSM has the tests for it but I need a "T" with the fittings to connect the gauge in the line.  They also show a leak down test that I'll do.  I'll also check the O2 sensor, maybe it is giving a false reading to the computer or the temp sensor.
JR

[Bikerjr1]

Well I found out why I was not running rich when I installed the 48# fuel regulator.  It seems the injectors that I thought were 19# type III were/were not.  Ford used several in their 5.oL V8s the ones I got were part# 0-280-150-710. At the stock pressure they give about 14#s.  After I installed the high pressure fuel regulator I was getting back to stock flow rates, maybe a little under.  No wonder it seemed flat past 3000rpm.  I've gone back to the stock injectors and fuel regulator.  I'll work on getting some other injectors that will work properly with the PR211.  I test drive it here in a bit as soon as the computer bleeds down.  I know short the cable to ground, but then I wouldn't have the excuse to type this update.  Nothing can be simple it seems.
JR

[sharpxmen]

alright, that makes more sense - it was not adding up 

Either way you should check why you were getting 55psi instead of 50 (it's not 48). You should check the stock FPR as well, it's 39psi with the vac port disconnected, about 31 with the vac reference on at idle.

I wouldn't recommend going higher than 44psi with stock injectors or the Ford 19# unless you have some other mods (other than high flow filter and t/b) like a cam for example