car runs like crap when mass ir plugged in

Discussion in 'Fox 5.0 Mustang Tech' started by fastford91, Aug 15, 2006.

  1. COULD is the important word there.
    When the computer doesn't see a MAF input signal it changes strategy. Regardless of OL/CL.

    The described condition does not exclusively point to the MAF meter.


    jason
     
  2. If you still have the original maf plug it in and see if the problem is better. Those things are extremely touchy. I had a chip burned for my setup and it wouldn't idle at all until I changed the tube in the maf, didnt think a 24 to a 19 tube would matter that much but it does. Also remove the diablo chip and see what that does.
     
  3. I would start by checking for a vacuum leak. 90 percent of the time when I run into issues where the car ran fine before mods it turns out to be a vacuum leak caused during the install.
     
  4. X2 for trying it without the diablo chip. I've seem alot of stangs (although newer but still) run like crap, found out it had a JET chip in it, took it out and voila, no problems, worth a try.
     
  5. maf problems

    i recently purchased a slightly used gt40 crate engine and it came with 30# injectors and matching maf...and my idle is all over the place sometimes not all the time sometimes it holds steady but when it starts surging up and down i can pull the plug to the maf and it levels out......the mechanic said that the maf wasnt reading right ,but any info would be appreicated its only at idle it runs great while driving especially WOT......any help would be appreciated....also i have a hypertech chip in my computer and the other guy didnt have one could that be the problem?
     
  6. Pull the codes from the ecu
    Yank the chip and see how it runs. If the problem persists, then pull the codes again.

    Disconnecting the MAF tells you little. Your mechanic should know that...
    All that happens when the MAF is unplugged, is the ecu jumps a 'limp' strategy.


    Pull the codes and see what you get...

    jason
     
  7. is there a way of changing the setting of an already calbrated 75mm mass air...it is set at 42lb and i have 19lb??!!!
     
  8. Most likely that is a ProM or PMAS meter.

    You will need to send it in to PMAS to get it 'recalibrated'
    That is the only decent option...



    jason
     

  9. yep. check out their website for details. http://www.massairsystems.com/

    it's $100+return shipping to recalibrate a pmas/pro-m meter.