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Ez efi surging at certain Rpm range only

Discussion in 'FAST Support Forum' started by Algamotorsports67, Mar 4, 2018.

  1. Algamotorsports67

    Algamotorsports67 Member

    Joined:
    Aug 11, 2014
    Hello

    I have the ez efi 2.0 system installed on a 355 sbc. 10:1 compression, iron heads, comp 280xfi cam with 1.5 ratio rockers. Victor jr open plenum intake. Auto trans. Running California 91 octane. Fast coil and ignition box, no erm’s or codes


    The problem I am having is that between about 1600-1900 rpms the engine surges, afr readings jumpfrom super rich to super lean and it never mellows out untill I get out of this Rpm range then it’s fine. I’ve tried, richer, leaner, more timing, less timing, different timing curves, advances etc and I can’t seem to shake this problem it just moves around in that 1600-1900 range sometimes it’s just at 1700-1750 then fine at 1850, etc. have also tried different heat range plugs.


    The other problem is I also have a similar “surge” when the throttle is just barely opened, say, crusing slowly through a busy parking lot before the TPS even reads 1% it doesn’t clear up until the TPS is at 2% same thing as above have tried timing, rich, lean, fuel adjustments etc


    Other than these two issues the car runs great everywhere else, part throttle everywhere but 1600-1900, wide ope. Throttle is great, cruising 70 on the freeway around 3000rpm it’s great


    Don’t know what else to try have emailed fast multiple times and have yet to receive a response. Any direction would be greatly appreciated, different tune? Bad sensor? Bad ecu? I’m lost
     
  2. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    Your problem sounds mostly like a timing issue. With your compression and octane, you should have your initial timing at 20 degrees. Since I believe you have the EZ EFI 2.0, this is easy. Use the Wizard reset first. Then...

    Use the settings found here in my post 99: http://www.cpgnation.com/forum/thre...-body-system-vehicle-2-an-81-gmc.26110/page-5

    These settings should totally eliminate any surge as soon as the fuel maps set, and the engine should idle easily at 750. If these settings don't work, you have ECU interference issues, a fuel line problem, or may need a new set of sparkplugs of the correct heat range or one range colder than factory - possibly even new plug wires. Your plug wires should also be 40 Ohm per foot spiral core.
     
  3. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    You should also check the distributor phasing is correct and that the cap and button is good.
     
  4. Algamotorsports67

    Algamotorsports67 Member

    Joined:
    Aug 11, 2014
    I will try the reset and check wires and plugs, distributor is phased correctly and a brand new fast dual sync after my previous dual sync failed, had same troubles with previous distributor as well
     
  5. Algamotorsports67

    Algamotorsports67 Member

    Joined:
    Aug 11, 2014
    Distributor looks fine did the wizard and your settings still has the surge/ wondering in the 1600-1900ish range. Fine everywhere else. Going to throw on a newer set of wires from my other 350 just to see if there is a difference and take look at the plugs
     
  6. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    Be sure the wires are 40 Ohm per foot spiral core and the plugs are new. Post some pictures of your wiring and positioning of the ECU, ignition box, and a screenshot of the handheld master screen at warm idle. Check for any header leaks.
     
  7. Algamotorsports67

    Algamotorsports67 Member

    Joined:
    Aug 11, 2014
    Ok, ecu is above the passenger kick panel under the dash,
    The ign box and coil are under the dash at the middle of the firewall (inside) 67 el Camino
     
  8. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    The ECU placement on the passenger kick panel is okay so long as none of the ECU wiring is running parallel and/or next to the blower fan wiring or other power or speaker wiring. The ECU injector harness wiring should also run by itself, across other wiring at an angle where it meets other wiring - including any secondary wiring.

    The coil and ignition box are of more concern. The coil should be under the hood near the distributor with its primary wiring twisted from the ignition box. Coil secondary wiring inside the vehicle invites interference - especially with the use of multi-strike CD ignition boxes. Also, none of the ECU main power and ignition box main power wiring should be run together to the battery. ECU power should be an isolated direct connection to the battery terminal connections. The ignition box main power can use a suitable +12 volt connection away from the battery with its ground connected to the engine block. If your main power wiring meets this specification, you may need a main power line filter condenser on the ignition box main power wires. What ignition box are you using?
     
  9. Algamotorsports67

    Algamotorsports67 Member

    Joined:
    Aug 11, 2014
    Running msd 8.5 super conductor wires , what do you run?
     
  10. Algamotorsports67

    Algamotorsports67 Member

    Joined:
    Aug 11, 2014
    Using the the fast e6 box all the wiring is separated pretty well, none of the efi wiring is run with power/coil/ignition wiring. If the box and coil were in the engine compartment it’s nearly the same distance if not closer to the ecu. The most I’ve ever seen is 003 erm’s
     
  11. Algamotorsports67

    Algamotorsports67 Member

    Joined:
    Aug 11, 2014
    Also no heater or ac so that area is pretty open under the dash
     
  12. Algamotorsports67

    Algamotorsports67 Member

    Joined:
    Aug 11, 2014
    Ecu goes directly to the battery on a separate run not near any other wiring
     
  13. Algamotorsports67

    Algamotorsports67 Member

    Joined:
    Aug 11, 2014
    So the coil and cd box are side by side directly behind the distributor just on the inside, just divide buy the firewall, I could bend up a shield to put around the two devices
     
  14. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    I run MSD 8.5 Super Conductor. They are 40 Ohm per foot spiral core and no problem.
    IRMs down low or at 000 doesn't mean you don't have an interference problem - it's just an Ignition Reliability number.
    The ECU placement and wiring sounds good.

    The issue with the coil and FAST E6 is not their proximity to each other - they can be mounted next to each other with no shield needed. The E6 sounds good in the dash where you have it - as long as it and the coil are a foot or more away from the ECU (the farther the better). It shouldn't have any long coiled wiring connections. The problem with the coil in the dash is interference with its primary wiring and other wiring in the dash, and possible secondary coil wire leakage.

    Post a screenshot of the handheld master screen at warm idle in neutral.
     
  15. Algamotorsports67

    Algamotorsports67 Member

    Joined:
    Aug 11, 2014
  16. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    This doesn't look terribly bad, but there is a problem somewhere. 1st, get the IAC down to twenty. Load and MAP are a bit high for your cam. Check for a vacuum leak. But, the fuel maps may need to settle down before seeing those numbers in the 50's and high 40's. Check the rear TBI throttle blades are closing at idle. This also looks like air or raw fuel could be getting to your O2 sensor. But, it could also be interference affecting the ECU.

    Does the exhaust smell rich?
     
  17. Algamotorsports67

    Algamotorsports67 Member

    Joined:
    Aug 11, 2014
    The exhaust can smell rich at times but nothing really bad, how do I get The IAC Down? I’ve done the adjustment to get the slider in the box on the start up wizard. There’s about 120 miles, both freeway and city speeds on this new tune you asked me to put in.
     
  18. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    The exhaust shouldn't be smelling rich anytime with that tune. With the slider in the box, the IAC should be 20 warm idle in neutral. Something is causing your engine to see loading. Check the MAP reading - key on, engine off. It should be close to 100. If it is, check the MAP sealing gasket and its port. Vacuum for your engine combo at idle should be higher than the MAP reading shown on your handheld. You could also have a problem with the O2 sensor and/or interference on the ECU.

    The current MAP and Load readings shown on your handheld have the ECU in "limp home" mode.
     
  19. Algamotorsports67

    Algamotorsports67 Member

    Joined:
    Aug 11, 2014
    Do you have a email or smartphone i can send a video that I have watching the master screen while the car is actually doing what I’m talking about
     
  20. Algamotorsports67

    Algamotorsports67 Member

    Joined:
    Aug 11, 2014
    Map at ign on not running 106....
     

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