New Rebuild No Idle

Discussion in '1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-' started by B-radster, Apr 22, 2014.

  1. My first EFI rebuild just curious on thoughts about a no idle I have. First its a 1990 Mustang 5.0. t5, 8.8 upgraded from 3.08 to 4.10, engine- .40 over, .01 shaved deck, .510 roller cam, ported gt40 heads, new valves and dual springs 190I, 160E, ported intake, port matched upper to lower intake and exhaust to 1 5/8 header, 70mm t body and intake(intake tube modified to fit, 24lb injectors, MSD ignition w/9.0 wires, motorcraft platinum plugs, 1.6 roller rockers set to resistance on push rod then 1/2 turn and locked down. 3/4" intake spacer portmatched to clear tall rocker covers. runs and sounds good(besides a rocker arm tick) over 2000 rpm. release pedal or linkage and she stalls. idle air is new, TP is new and set at .92-.93v but the MAF is stock for a 55mm intake and 19lb injectors. Lets hear some thoughts on what is causing the no idle out of my 2 choices or something else I haven't thought of.
  2. Unless you gave us bad info, this is a big problem. You can't run 24# injectors with a MAF setup for 19# injectors. Get an aftermarket MAF calibrated for @24#
    B-radster likes this.
  3. Winner winner chicken dinner
    B-radster likes this.
  4. One more thing, 1/2 turn wasn't enough. Check out this video, this guy has a rule of thumb of min 1 full after push rod resistance.


    Attached Files:

  5. a
    All info is correct. I just moved TP sensor to 1.0volt and problem remains. I thought cpu would relearn the overage of flow but after reading a lot of posts I am also thinking the MAF needs to be upgraded. Seems to be a common issue with injector upgrades.
  6. hmmmmmm......... perhaps this is why it sounds loud to me.....
  7. Unless you get a certain type of tune that eliminates your need to use a MAF, you have to calibrate the MAF to your specific size injectors or it'll run like crap. I have a ProFlow (ProM) and most people recommend them as well. You want it to be bigger than your throttle body, so 75mm would be good for you.
  8. It sounds like you have a nice car your building, pics?
  9. Thanks for the Tip. Do you know of a decent place to purchase? I don't want some china pos off ebay for $10. LOL
  10. trying to upload them now. it says uploaded and saved but they aren't showing up on my profile or avatar

    P.S. I see a white GT mustang in your avatar. Also when replying, click "upload a file" next to "post reply" to show pictures in your post.
    B-radster likes this.
  12. Fix you MAF problems first: get a quality MAF that is matched to the 24lb injectors.
    The OEM Ford MAFs are not calibrated to injector size. The injector sizing is done in the computer’s internal programming. Aftermarket MAF’s “lie” to the computer in an attempt to fool the computer into changing the injector pulse on timing to match the increased airflow.

    After that if you are still having idle problems, here's the answer...

    You guys with idle/stall problems could save a lot of time chasing your tails if you would go through the Surging Idle Checklist. Over 50 different people contributed information to it. The first two posts have all the fixes, and steps through the how to find and fix your idle problems without spending a lot of time and money. I continue to update it as more people post fixes or ask questions. You can post questions to that sticky and have your name and idle problem recognized. The guys with original problems and fixes get their posts added to the main fix. :D

    It's free, I don't get anything for the use of it except knowing I helped a fellow Mustang enthusiast with his car. At last check, it had more than 134,000 hits, which indicates it does help fix idle problems quickly and inexpensively.
  13. I love the "NO NO" picture about the cone filter and then you look at my engine picture where i set it up for the picture and it looks the same. LOL mine is NOT set up like that it actually is in the fender area to get cooler air. Lots of good tips on that page. I didnt know about the Fusible link in the O2 wires. Thanks!
  14. Glad to help.
    Like I said, fix the MAF problems first. A good Pro-M MAF will get the mismatch fixed.
    See or for more on Pro-M products
  15. Good guys and they know their stuff!
  16. That won't match the injectors you have without a custom dyno tune & chip burned from the dyno tune data.
  17. Pro M 75MM MAF for 24lb ers and call it a day. For the Rockers, what do the instructions for the ones you have say. Are they high rev anti pump or stock lifters. Sometimes you need to have them looser, sometimes tighter. Depends on the cam, lifters, and manufacturer. On that video, those rockers did not have poly locks- do yours?
    #20 mikestang63, Apr 23, 2014
    Last edited: Apr 23, 2014