Results 1 to 10 of 14

Thread: Idle and just off idle issues with Avenger 550-400

Hybrid View

Previous Post Previous Post   Next Post Next Post
  1. Default Idle and just off idle issues with Avenger 550-400

    Hi,

    I have installed a 700 cfm Avenger EFI sytem on my 318 powered '65 Valiant. I have adapted a Chrysler Lean Burn distributor to an 8 pin GM HEI module, and using the Holley harness connector I have ECU controlled timing.

    Naturally I've followed the instuctions to the letter, and set the timing as per the manual. I've used the Megasquirt manual to connect the module and distrubutor properly.

    I am having issues with idle and just off idle light cruise. At idle the RPM is set to 800, and the engine surges badly. When it does the AFR reading on the hand control goes lean. If I am cruising at just off idle RPM, say around 1250, the car stumbles and surges badly and the AFR can go as high as 19:1. If I open the throttle sharply the problem disappears, but if I open it slowly, or keep it stable, I can repeat the fault over and over.

    AFR for idle is 13:1, cruise is the same.

    Can someone please advise how I can solve this, or what is possibly causing it. I'm ripping my hair out.

    Regards,

    Robert

  2. #2
    Join Date
    Dec 2009
    Location
    Connecticut
    Posts
    22,400

    Default

    Are the throttle blades (idle speed screw) properly set to achieve an IAC Position of 3% at hot idle?
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: Dominator MPFI & DIS, 100HP progressive dry direct-port NOS, A/C, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/off-road X-pipe/shorty headers, 160A 3G alternator, Optima Red battery, S&W subframe connectors, LenTech Strip Terminator wide-ratio AOD/2800 RPM converter, M4602G aluminum driveshaft, FRPP 3.31 gears, Cobra Trac-Lok differential, Moser 31 spline axles, '04 Cobra 4-disc brakes, '93 Cobra booster & M/C, 5-lug Bullitt wheels & 245/45R17 tires.

  3. Default

    Yes, and I have done a TPS autoset several times and just done firmware upgrade. Still no improvement alas.

  4. #4
    Join Date
    Dec 2009
    Location
    Connecticut
    Posts
    22,400

    Default

    Has the EFI system finished learning in the trouble area?
    Engine must be at normal operating temperature and ran at steady-state RPM.
    You should view a data log of this stubborn spot and look for what's causing it.

    Ensure there are no exhaust leaks upstream of the WBO2 sensor.
    Ensure the ignition timing (timing light) is synchronized with the ECU.
    Ensure the fuel pressure is set correctly at 21 psi.
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: Dominator MPFI & DIS, 100HP progressive dry direct-port NOS, A/C, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/off-road X-pipe/shorty headers, 160A 3G alternator, Optima Red battery, S&W subframe connectors, LenTech Strip Terminator wide-ratio AOD/2800 RPM converter, M4602G aluminum driveshaft, FRPP 3.31 gears, Cobra Trac-Lok differential, Moser 31 spline axles, '04 Cobra 4-disc brakes, '93 Cobra booster & M/C, 5-lug Bullitt wheels & 245/45R17 tires.

  5. Default

    I have to get a more accurate pressure gauge, but the one I am currently using is reading 20 PSI. No exhaust leaks and timing is synced.

    One thing I don't understand, is that I get a message on the bottom of the tuning screen saying "dirty", when I connect the ecu to the laptop. If I open the software and don't connect the ECU, it says "clean". Is this important?

  6. #6
    Join Date
    Dec 2009
    Location
    Connecticut
    Posts
    22,400

    Default

    Quote Originally Posted by robertodonnell View Post
    One thing I don't understand, is that I get a message on the bottom of the tuning screen saying "dirty", when I connect the ECU to the laptop.
    If I open the software and don't connect the ECU, it says "clean". Is this important?
    No, that doesn't mean anything to the end user.

    With my previous Holley TBI system, I ran 23 psi of fuel pressure but
    only because the four 75 lb/hr injectors were almost too small for my engine.
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: Dominator MPFI & DIS, 100HP progressive dry direct-port NOS, A/C, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/off-road X-pipe/shorty headers, 160A 3G alternator, Optima Red battery, S&W subframe connectors, LenTech Strip Terminator wide-ratio AOD/2800 RPM converter, M4602G aluminum driveshaft, FRPP 3.31 gears, Cobra Trac-Lok differential, Moser 31 spline axles, '04 Cobra 4-disc brakes, '93 Cobra booster & M/C, 5-lug Bullitt wheels & 245/45R17 tires.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
About us
Holley has been the undisputed leader in fuel systems for over 100 years. Holley carburetors have powered every NASCAR® Sprint® Cup team and nearly every NHRA® Pro–Stock champion for four decades. Now, Holley EFI is dominating the performance world as well as our products for GM's LS engine. Holley's products also include performance fuel pumps, intake manifolds & engine dress–up products for street performance, race and marine applications. As a single solution, or partnered with products from other Holley companies - Hooker Headers, Flowtech Headers, NOS Nitrous, Weiand, Earl's Performance Plumbing, or Diablosport - Holley products can give you the edge you need over the competition.
Join us