Garbage gas mileage, 10mpg

Discussion in 'Fox 5.0 Mustang Tech' started by Grn92LX, Sep 12, 2004.


  1. Grn92LX

    Grn92LX Fidanza Man! Founding Member

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  2. 5spd GT

    5spd GT "the 5.0 owns all" Founding Member

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    Just start replacing sensors and hopefully one of them will help out :D ...or a tune will do it all... :nice:

    Basically "tTt"-ing for ya....
    #82
  3. Grn92LX

    Grn92LX Fidanza Man! Founding Member

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    I'm not getting a chip tune. I tried that once and got f vcked,stupid cokksuckers. Did I ever mention to you I hope that place burns down? :D I might change some sensors, who knows. I'd like to get new coolant temp and longer wire 02's. I just dont wanna spend $150 on sensors.

    Im also thinking (again) about saving for a shortblock. Just a basic 10.7:1 347 with a cast crank using the CHP rotating assembly. I dunno what I wanna do. maybe this week i'll try a few local machine shops for price quotes. The shop around the block is pricey, but the guy is really nice.
    #83
  4. stangbear427

    stangbear427 Active Member

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    When's the last time you had your drums off? Just heading off in a little different direction since this thread hasn't died yet. If you have something like an ebrake cable sticking even a little bit, you may not even notice it at all- but it'll still slice 8mpg right off your average. Happened to me, just passing it on. Continued good luck :shrug:
    #84
  5. Grn92LX

    Grn92LX Fidanza Man! Founding Member

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    I had my rear drum brakes 'dragging' once. Cost me my first 12 second slip at the track. Car went 13.1 @ 104, readjusted the brakes because they were way too tight and if I think the next time I went after that I went 12.80's @ 107. Not all the brakes fault, better weather too. I will check that, I did re adjust the drums a few months ago because I had them a touch too loose. I dont think its an issue, but i'll check eventually.
    #85
  6. Grn92LX

    Grn92LX Fidanza Man! Founding Member

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    I think friday im gonna swap thermostats. I have 2 to choose from, either a motorcraft 180* with 1/8" hole drilled in it or a mr gasket 195*. I'll probably drivew it around a little and fill up before swapping to see if theirs a change.

    I might try 2 machine shops around here for a price quote to build a shortblock too with me spuulying the rotating assembly and block :D
    #86
  7. 5spd GT

    5spd GT "the 5.0 owns all" Founding Member

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    Well so far I got 230miles to the tank (not accounting for the wrong speedo gear so it is probably a bit less)...and I got 1/4 tank left before it runs out...

    A dyno tune (w/ chip) would be much better for your car (as well as mine)...did those "burned down guys" not tune your car on a dyno...they just did it for your "combo" right?...no wonder... :nonono: I hope it burns down to :nice:

    Hey what happens if you left off the clutch right where it "slips" and you go...I revved it up to 4k by accident trying to keep it from dying...I almost let it out to quick and got the clutch "caught" in the engaging zone...and I thought I smelt a burning smell again...lol...I only got about 120 miles on it so far...surely that didn't hurt it right?
    #87
  8. 5spd GT

    5spd GT "the 5.0 owns all" Founding Member

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    Hey how do you adjust the brakes or make sure there not catching...I know my e-brake won't hold the car anymore...I have to stretch the handle very high to get it to keep it from rolling...but any more than a 20* slope and it wants to roll...is it just the shoes needing replaced or the cable or adjustment?
    #88
  9. Grn92LX

    Grn92LX Fidanza Man! Founding Member

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    No, that shop burned my chip on a dyno. It was an autologic chip. WOT a/f was good, but driveability sucked!

    My car does the same thing if its on an incline. I have to pull the brake up real high and it still might roll lol. On the inside of the brake (the side facing the differential) theres a rubber plug and if you take it off you'll see where you can adjust the brakes w/o taking the rims and drums off. You need a flat head screwdriver.

    Wow, 230 miles to the tank is nice. When you fill it up, do the math and lemme know. Thats probably around 16-17 mpg.

    Sounds like you just rode the clutch and burned it a lil. Nothing to worry about, stuff happens.
    #89
  10. 5spd GT

    5spd GT "the 5.0 owns all" Founding Member

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    Didn't you get that "tune" with the new parts on (MAF, TB)...what gains did you get? Okay if they couldn't get a proper tune and run right...they do need to burn down... :nonono:

    I'll have to take a look at the brake thing...next week I'm putting on my valve covers (w/ gaskets)...readjusting the valves, installing new harmonic balancer, cap, rotor, plugs, wires, pcv valve, and recheck the tightness of all the bolts, and fix my coolant leak out the head bolts...will do it all as one...and will check to see if my clutch is grabbing out all the way...it grabs about an inch and a half off the floor (from being mashed into the carpet)...that was with the rear jacked up and when I noticed the wheels starting to spin...

    I'm going to fill up my tank tonight and do another tank...driving fairly easy...and write down how much I fill it up...and then when I go to fill it up again I'll do the math...

    I know on a highway I could get another 60-70miles out of it adding that on to the 236 (currently)...but I don't drive straight shots...I might check into getting a new speedo sensor and see if that fixed my bouncing speedo...it only does it to like 20mph...the new gear helped out...

    I hope so...I didn't want to screw up my clutch already...
    #90
  11. Grn92LX

    Grn92LX Fidanza Man! Founding Member

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    Ok, heres an update. I put an old mr gasket 195* thermo in today and now the car runs hotter, about 200*. I'll see if this improves my mileage at all. I also noticed one of my rear tires was 4lbs low on air so I filled it back up. I filled my tank up, did the math and I got 13mpg. The gauge was at the line below the 1/2. This tank was al around town driving and some beating on it. I guess the new maf (and 75mm tb) helepd the mileage because 2 tanks ago I only got 10 and that tank also had some highway driving on it. This mileage is still crappy IMO. I'll see how this tank goes with the car running much hotter now. After this test (depending on results), I think im gonna put a motorcraft 180* thermo I have in the garage in. I dont like this running 200* stuff :) UNless my mileage magically jumps to like 20mpg or soemthing :lol:

    David, to answer your ? from above, no, my chip tune was with the old 24lb maf with the 30lb injectors in the car and 65mm TB. Any good shop can design a custom maf curve. I had that done in march. The new tb and maf were done last week. Yes, they need to burn. I find it funny that with my used $85 optimizer I had the car running better myself than they ever could with their pathetic chip and useless tuning skills.
    #91
  12. Michael Yount

    Michael Yount Advanced Member

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    Hard to say - I wonder if it's just a combination of not the best maf/transfer function match, and the cam/combo isn't making much torque down low (street driving - below 2400 rpm) - which means it's real inefficient at low engine speeds.
    #92
  13. 5spd GT

    5spd GT "the 5.0 owns all" Founding Member

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    I run a Motorcraft 180* thermo...

    Where's the matches :nice:

    Well Mike...I'm thinking I need a new bearing retainer (I noticed when I took off the transmission that when I would slide the TOB left and right with the clutch fork that the retainer is "spun" on would hit the input shaft gear...I wonder if that could cause my vibration in the clutch pedal...? That means I got to pull the transmission again... :mad: ...Easy...but I don't want to do it...

    I'm pretty sure that is my problem I'm just trying to get a confirmation on it?
    #93
  14. 5.0 HOtrain

    5.0 HOtrain Founding Member

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    Just go 351 stroked and be done with it

    Hell, I have you're first post beat, I get 10.5mpg :rlaugh:

    With my over injected (30# :rlaugh: ) afr/fti combo I got 17-20mpg around town, and 24-26mpg on the highway, with a tremec and 3:73's :shrug: I dont know about you're speedo gear though, mine seems dead nuts perfect with the 7/21 set up :shrug: Screw them sensors, put a carb on it :p

    I think i'm going to go with a performer rpm air gap on mine next year instead of the super victor, that'll be my only change this winter. Good luck mike.

    mike.
    #94
  15. QDRHRSE

    QDRHRSE New Member

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    Here we go again with the Volvo crap (jk)!!!! Hey Mike, if that Volvo junk is so cutting edge, why are you sporting a 5.0 (jk2)?I remember once at band camp there was this guy that drove a Volvo.....

    Anyway, I've heard that you should never cut the wires on the sensor and that you should extend the car's harness. Supposedly those sensors are operate at relatively low voltage and are very sensitive. Just my $.02 .
    #95
  16. Grn92LX

    Grn92LX Fidanza Man! Founding Member

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    david, what temp do you normally run at? What does it run at at night when its cooler now?

    Mike (ho train) isnt that some s hit how we get the same gas mileage and you have a big inch carb'd winsdor? LOL

    Qdrhrse, thats another thing im thinking since I did cut and lengthen my O2 wires. Ill see how this thermo test goes first before buying new O2's.

    Michael Yount, my car used to get very decent mileage. Im talking about 16mpg with mixed driving. That was when I had 24lb injectors and it ran lean. I believe this started when I did the 30's to cure the lean issue. Makes more power now im sure, but gas mileage went down. I dunno if thats the exact reason though. My cars makes decent low end at that low of an rpm, so I dont think thats the issue. When im driving it around normal, I shift around 2500.
    #96
  17. 5spd GT

    5spd GT "the 5.0 owns all" Founding Member

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    Hmm...well I don't think this will help you much but before I installed the Griffin Radiator (31x19) and 180 degree thermostat the stock guages read (the previous owner put them on...don't know how accurate they are)...between the R-M on NORMAL...and know after the h/c/i swap with the addition of the radiator and thermostat it reads at the top of the "L" in NORMAL...

    I need to get "real" guages...
    #97
  18. Grn92LX

    Grn92LX Fidanza Man! Founding Member

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    Yeah some autometer gauges will be a nice investment for you and they wont cost an arm and a leg. I have coolant temp and oil press in my center vents and aside from being functional, they look really cool too at night with the green bulb condom (no, not the trojan twisted pleasures you sicko :D)

    My first start up idle for the day sucks and has got worse. Now it'll stall right away on the first start and it'll try to stall on second start unless I give it gas. This horrible idle stops after 2-3 min. Im guessing it goes into closed loop then. I think im gonna disconnect the battery over night when i get a chance and erase the KAM and see if the car can learn a better idle. Im also gonna put my motorcraft 180* stat in after I get the gas mileage from this tank to see if the hotter running temp effects my mileage.
    #98
  19. 5spd GT

    5spd GT "the 5.0 owns all" Founding Member

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    Yeah the same happens here...my car doesn't stay started after I start it...I have to stay on the gas for 25-30 seconds...and the car has a really delayed rev until it is warmed up?
    #99
  20. Grn92LX

    Grn92LX Fidanza Man! Founding Member

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    Update: I did my gas mileage with the hotter running car since I had a 195* stat. Gas mileage went down the drain to about 8mpg. I lost 5mpg from last time. I guess its safe to say the hotter running car doesnt help mileage or at least on my car it doesn't. I put in my old motorcraft 180* stat today and its perfect. I dont know how the hell I managed to get 8mpg. Im thinking its definatly a sensor. Possibly o2's, or o2's plugged into the wrong harnesses or they arent working right due to my splicing in to extend the wires or a bad coolant temp sensor.

    I think im gonna try and solve this problem by doing a new engine :D 10.5:1 347 with ported TW heads, TFS R intake and a jay allen custom grind cam. Im hoping to pull the car apart in 2 weeks once I definatly decide if I wanna spend the money to do this. I am hoping to go to the track next friday night so maybe the weekend after I will tear it down.

    Mike

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