Running WAYYYY to rich! help!!

Discussion in 'Fox 5.0 Mustang Tech' started by 88vert5.0, Feb 1, 2009.


  1. 88vert5.0

    88vert5.0 New Member

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    so i have a pretty nice mild built motor and she is running very very rich. its a mass air conversion and has 24lb injectors and a new fuel pump and new o2 sensors and a wideband air/fuel ratio. we also got it tuned with an SCT chip. the car has many other mods if you can see on my profile. but we and my mechanic cannot figure it out and this guy has worked with ford for many of years. any ideas?
  2. bubba-dough

    bubba-dough Active Member

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    I take it it was a mail order tune chip because had it been done by a tuner you wouldn't be having any issues.

    I would try tuning the car without the chip or take it to a professional tuner.


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  3. 88vert5.0

    88vert5.0 New Member

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    Thats the thing thats weird this guy has been tuning mustangs for awhile through SCT. Every car that has come to his shop has been easy for him for some reason and he just cant figure out whats wrong with mine. plus its hard cuz my car isnt OBD2 obvioulsy and it sucks ha. but the thing is, is he didnt dyno tune it he just did it on his laptop.
  4. vristang

    vristang Advanced Member

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    Post the specs on the MAF...
    brand?
    calibration?
    Did you buy new? where?

    You have 3 O2's in your exhaust? 2 stockers, and one WB hooked to a gauge?
  5. Mike in Texas

    Mike in Texas New Member

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    Running Rich

    What MAF are you using?
  6. 2002BLGT

    2002BLGT Well-Known Member

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    1988 mustang vert LX, mass air conversion, 308 block, B303 cam, gt40 heads, polished cobra upper and lower, bbk cold air intake, 70mm throttle body, 24lb injectors, underdrive pulleys, mac shorty headers, mac 2 1/2 inch x pipe, mac 2 1/2 pro dumps,
    373 gears, ton of extra stuff!!!

    AGAIN what MAF is on the car ? Try installing another MAF and take it back to the tuner , for what you have you dont need a chip just to get it to run , pull the chip , and get a MAF that is calibrated for 24s and it should run just fine , did the tuner check your base timing , fuel pressure etc ?
  7. 88vert5.0

    88vert5.0 New Member

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    he did check the fuel pressure and timing and everything. the MAF is from a 1990 lx. he said he calibrated it to 24lbs.
  8. 88vert5.0

    88vert5.0 New Member

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    oh and yea i have 3 o2s one for the wideband and two stock o2s
  9. Mike in Texas

    Mike in Texas New Member

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    Running rICH

    My bet is on the MAF. I just changed my C&L for a pro M and it fixed my running rich problem.
  10. bubba-dough

    bubba-dough Active Member

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    Your car not being OBDII has nothing to do with tuning it properly. The SCT tuning software is awesome. I don't understand that if your tuner is an authorized SCT tuner why he can't get it right. I mean he can see everything little thing the car is doing at every rpm. He can see the maf curves, fuel curves, injector duty cycles, and the list goes on. So without that info we would just be shooting in the dark. I have witnessed countless 5.0s tuned at a nearby SCT tuner. They have came in with all sorts of issues and everyone of them left perfect. By any chance are you supercharged & running a fuel management unit. FMU's are bandaids and 99% of tuners with throw them out the door because they wreak havoc on a tuner. They will cause a car to be lean until boost picks up then they throw the fuel at it. IMHO I would find a new tuner.
  11. 88vert5.0

    88vert5.0 New Member

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    i wish i was boosted but its just a naturally aspirated car for now anyways. and i agree the guy should be able to find out everything about my car on the SCT tuning especially since hes an authorized member but the guy swears up and down hes checked everything out. He said no car has every gave him this much trouble before. the longest he has a car is for about a week. WOuld it be best to just go to an actual dyno to get it tuned? Im thinkin about just getting a new MAF made for 24lb so ill know for sure that it is. 50resto.com has some for around $130. i also know another guy that does amazing work but its all diablo tuning.
  12. 88vert5.0

    88vert5.0 New Member

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    So we put in a new computer and she ran amazing. did it just for fun and then when i took it out for a test run it went back to her old self but now she goes insanely lean to very very lean. we pulled a code from her and it says low signal from ground from MAF.
  13. Mike in Texas

    Mike in Texas New Member

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    Running lean

    I'm still betting that the MAF is the problem.
  14. 88vert5.0

    88vert5.0 New Member

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    alot of progress on the car. i finally got a new guy who has made software for 5.0s to help. he hooked up a air/fuel tweeker between the MAF and the harness and we played around with the throttlebody and shes running a million times better. i appreciate everyones help on here with all the ideas and everything. im looking at getting a Pro M 75mm 24lb MAF for 209.99 on 50resto.com. i guess the old guy pretty much lied telling me he calibrated my MAF to 24lb when he didnt. and that chip is not on the car anymore were running the stock computer for everything. this new guy had helped made a low 10 sec 125 shot fox running on nuthin but a stock computer. i guess next to come on my car an vortech Strim
  15. fstrbz

    fstrbz New Member

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    i was wondering what magic wand he waved over that maf to calibrate it at his shop? i would get the pro-m or pmas calibrated for 24's or 42's and go get that supercharger
  16. Foxfan88

    Foxfan88 My Grandpa has great wood.

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    He did lie when saying he "calibrated" a stock MAF. in the tuning world when you actually tune the EEC, the word "calibrated" means nothing.

    what i mean is a MAF is a MAF, with an actual tune you could run a stock MAF with 42# injectors, you could also run say a "calibrated for 42s" maf on an engine with stock injectors. its all about entering in the proper maf curve for the actual meter on the car and also the injector slopes for the actual injectors on the car.

    the "calibrated" mafs are nothing more than a hack way to fool the EEC into getting the correct AFR. they throw off load calculations within the EEC also.

    they're designed to be put on un-tuned EECs (that still think they have stock maf and injectors)

    the theory on them is sound but ive found in the real world and with the variance b/w every car. there arent going to be perfect. 9 times out of 10 the car will drive decent but if you get a WB you will be able to see the errors. but some cars seem to do great with them but other seem to not run right with them.

    IMO tuning is the best way.
  17. 95Vert383AOD

    95Vert383AOD Active Member

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    +1 on the MAF

    I had my 383 on an A9L computer. Used a C&L pipe. Started up and ran perfect before i even tuned it....No rough idle, no surging......i had all accessories Smog & A/C etc. This is using a Computer designed for a 5.0 mustang on a 6.3 liter motor.

    In the computer world they say "garbage in garbage out" an improperly calibrated MAF will throw the computer off.

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