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Thread: Slight Flutter at Cruising Speed

  1. #11


    I started with Custom Global File "350/383 14PSI Supercharged". It had a Target AFR of 14:1 in that zone. I'm wondering why twice yesterday it went Off Line and displayed communication problem with ECU? I did not start a Datalog. My FM Radio keeps turning on with the key and I forgot to shut it off. It's not tuned to a station and I could hear static when I plugged the USB Jack and when I clicked V5 Icon. I've often wondered if the little electronic FM Antenna stuck up in the corner of the windshield could be an RFI problem? It's wire runs down the Pillar and over the top of the Glove Box along with the right side speaker wire. The ECU is on the Glove Box Door. I believe that Antenna has a Switched Hot.

  2. #12


    I've had issues with my USB cable being near "noisy" wiring, causing the ECU to generally act weird and actually shutdown.
    Last edited by bWright; 05-30-2020 at 09:45 PM. Reason: typo
    351W, 800HP stock shortblock assy

  3. #13


    Was the MAP sensors data screwed? I did switch from a Pro Flo 2 intake that fits the Weber throttle body only (not a standard square flange) to Edelbrock Victor JR. EFI, the Vic JR. does not have a boss cast in the Base Flange to seat the gasket at the Idle air passage. So a steel plate is supplied with the throttle body to achieve a seal which defeats the purpose of spending a lot of extra money for a 1/4" of hood clearance. And throttle lever clearance required grinding under the top hat and double gasket on the hat also. I feel it's highly unlikely it's the manifold, I used silicone around the ports and sanded the cork end rail gaskets down to 50% thickness prior to Right Stuff sealing them.My Dyno session was a joke! It wasn't a session. I deposited $200.00 for May 27 9:00 AM appointment and traveled 150 miles towing a 30' trailer. There was a car on the Dyno. I was told "in order to do a proper cold start tune it would need to be left overnight". I trailered back home and called at closing time and was told the driveability tune was achieved. When I called in the morning they told me the Dyno was rented until noon. When I got there at 11:30 AM I went to inspect my artwork and found the fuel pump running. when they were doing full pulls the Owner said the air charge is 130°. I said the temp sensor is upstream 1" from the W/M nozzle and he replied it is a myth that W/M cools the charge, it only raises Octane. That is scientifically False. They also deny the threat of corona virus as they operate as an Essential Business in a phase 1 shut down and as a Leukemia (CML) Patient they put me at risk. When I got it unloaded and took it for a test run, the first time I squeezed it the W/M did not come on. After trouble shooting I found the Hobb switch activating at 10 PSI. I Emailed "Please tell me you didn't adjust that" and have NO RESPONSE. They also believe that soft fuel limiter will blow up the engine. My logic disagrees. I wasted $972.00 for there "disservice", 600 miles on 12 tires and 2 full days. Holley Tech recommended this Business and that is the ONLY reason I chose them.The shop owner said it is not true that the system could make changes to compensate for an injector swap. It doesn't need the 80s. they were recommended by another EFI Tech Co. I got these 80s from TRE for $350.00, could they be knock-offs? It ran sweet in 2018 with the 60s and Pro Flo 2. Today I swap Injectors.

  4. #14


    Problem Resolved. While using the SWAG method to determine if perhaps the WBO2 sensor was the root of the wild lean pops and stuttering, I disabled Closed Loop below 2500 RPM, and went for a test run thinking if it runs good at cruise (-8.0 on the PSI Axis @ 2000 RPM) that would indicate a Faulty WBO2 sensor. What I found was that it ran at 15:1, 16:1 and Off Scale, Popping out the pipes. This indicates that the Base Fuel Table is massively Lean and the fluttering and popping was the system flickering in and out of Closed Loop. The Datalogs confirm this. I restored Closed Loop at all RPM and while driving the perfect Rural Road, I held steady, rolled in, rolled out of the throttle, all the while Transferring Learning To Base about every 30 seconds. It cleaned up quite well and I'm confident proper fuel mapping will resolve the Issue. The mistake I made was,Smoothing every time I transferred Learning.By the time I got home it was so fat at Idle (I guess Closed Loop was getting finicky) that it wouldn't run. I used Idle Speed Control to keep it running at 1500 RPM and slowly Transferred Learning, not smoothing, until it would Idle at 770 RPM at TAFR 12.8:1. I have an appointment for 8-28-2020 with a True Tuning Professional, EPC Racing in Spokane.

  5. #15
    Join Date
    Dec 2009


    Quote Originally Posted by dynosore View Post
    ...all the while Transferring Learning To Base about every 30 seconds.
    That's not necessary.

    I have an appointment for 8-28-2020 with a True Tuning Professional, EPC Racing in Spokane.
    This is necessary.
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: 385" SBF, Dart SHP 8.2 block, TFS T/W 11R 205 heads, 232°-244° duration/.623" lift/114° LSA camshaft, 12:1 C/R, TFS R-Series FTI ported intake, BBK 80mm T/B, Dominator MPFI & DIS, 36-1 crank trigger/1x cam sync, 200A 3G alternator, Optima Red battery, A/C, 100HP progressive dry direct-port NOS, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/off-road X-pipe/shorty headers, -6AN fuel system plumbing, Walbro 255 LPH pump, S&W subframe connectors, LenTech Strip Terminator wide-ratio AOD/3000 RPM converter, B&M Hammer shifter, FPP aluminum driveshaft, FPP 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 M/T Street Comp tires.

  6. #16


    Quote Originally Posted by Danny Cabral View Post
    This is necessary.
    Absolutely, I should have made the appointment six weeks ago. It was about a month ago, I was talking to a Holley Rep about the I/O harness and he asked my zip code and recommended the shop I went to. Now I'm confident there's not a mechanical issue. I did a cold leak down test, which was overdue and found 14% on the best and 19% on the worst, prior to dyno. But after rolling along smooth at 2000 RPM and rolling up then decelerating smooth, sounding the way a performance engine should, I was relieved. It's 378 miles and Sea Level to a 4000' Summit to Spokane, but clearly worth it.

  7. #17


    Sounds like a long way to drive for a tune session. If you have WiFi and a laptop, you can do a remote tuning session with someone like FAST Man EFI.

    Testing in Open Loop is a good thing to try. I like to have the Base Fuel Table dialed in so that all numbers in the Learn Table are single digits. That way the ECU doesn't have to chase its tail all the time, and if something goes wrong it should run okay in Open Loop. It usually takes some work to get there.

  8. #18


    Quote Originally Posted by dynosore View Post
    The flutter at light load cleared up when I changed the Target AFR from 13.5 to 13.0.
    What's probably happening is cylinder imbalance. A few cylinders were way leaner.

  9. #19


    That's very possible, especially if it's an intake designed for a carb rather than for EFI. I've had engines where I just have to use individual cylinder tuning to get rid of that. Some race intakes are pretty bad at part throttle, even if they even out at WOT.

  10. #20


    The old Pro-Flo 2 manifold was always Rich AFR on the four corners, or Lean on the middle four. But this is a new Edelbrock Victor JR EFI and I really can't say yet about it.

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