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Thread: 5.3 LM7 Terminator X - starts then stalls.

  1. #11
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    You're getting lots of vacuum. I don't think this is your problem. Give it more fuel and find out if that's it.

    It looks like you have Individual Fuel Cylinder Correction. Go there and up the fuel in every cylinder by 10%, then do a second test and add another 10%. Datalog the results.

  2. #12

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    To make sure I understand correctly, you’re suggesting increasing the fuel in ~10% increments across all cylinders, would this be for an RPM range? Or a discrete RPM target? Sorry, I’m relatively new to this and want to make sure I’m adjusting in the right areas.

  3. #13
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    Go to Individual Cylinder Fuel Correction (System ICF) and add the fuel to all cylinders. This will add fuel at all RPM ranges. This is a test to see if your problem is a lack of fuel. If it is a lack of fuel you will need to correct the problem in your Base Fuel Table.
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  4. #14
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    Quote Originally Posted by 81 TransAm View Post
    This is a test to see if your problem is a lack of fuel. If it is a lack of fuel you will need to correct the problem in your Base Fuel Table.
    Thanks for adding this clarification.
    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.

  5. #15

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    Update: I went ahead and increased fuel by +10% across all cylinders in the EFI software. I also updated my firmware to the latest version, again.

    Attached are four datalogs. The only change I made in the configuration was the increased fuel. This actually seemed to help as it idled longer than it has in a while. However, it still ended up stalling out after attempting to idle down. A few observations from these attempts:
    1. AFRs appeared to be richer than they have been, which would make sense with increased fuel.
    2. Idling surging quite a bit as the ECU attempts to maintain a steady AFR target.
    3. Any modulation of the throttle seemed to cause the engine to hiccup or choke out and seemed to exacerbate the stalling.

    Can you take a look at the datalogs when you have a moment and offer any thoughts on what to do next? Is there any way to definitively rule out clogged injectors as a culprit? To me this seems like a possibility based on the symptoms I'm seeing. I just don't understand why it seemingly ran well initially and now I'm facing these issues. Could a faulty Fuel Pressure Regulator cause or compound these issues as well? I'm still using the factory diaphragm style FPR mounted on the fuel rail. Thank you in advance!
    Datalogs and GCF 090720.zip

  6. #16
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    Did you try adding 20% fuel? It is staying running long enough for the Closed Loop to come on? Look at what your Closed Loop is doing. Once the After Start Enrichment runs out and the Closed Loop comes on, it's still lean, so the Closed Loop adds a lot of fuel. But it overshoots your target and goes rich, then it pulls a lot of fuel, overshoots and goes lean, and it keeps doing this. When you touch the throttle, it takes it out of Closed Loop and goes lean.

    For the next test, add another 10% fuel. Then lower your Closed Loop Advanced Control from 3 to 1, this will slow down the how fast the Closed Loop reacts. Remember these are only tests to determine your problem. Once you determine that fuel is your problem the Base Fuel Table will need to be adjusted.

    You also need to get the engine up to operating temp so the Learn comes on and then you can see how much fuel your engine needs in the idle area.
    Last edited by 81 TransAm; 09-07-2020 at 08:35 AM.

  7. #17

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    Thank you for the quick reply! It does stay running long enough to switch in Closed Loop, which is when things start to act strange, to your point.

    I haven't tried 20% increase yet, I will do that and report back, along with the Closed Loop Advanced Control from 3 to 1. Should I adjust anything with Closed Loop Compensation Limits? Right now they're set at +50%/-50%.

  8. #18
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    Quote Originally Posted by bpray9223 View Post
    Should I adjust anything with Closed Loop Compensation Limits? Right now they're set at +50%/-50%.
    Yes, initially set all those Closed Loop & Learned Compensation Limits to 100%.

    When the engine is tuned & running well, you should decrease the Closed Loop and Learned Compensation Limits % to lock in a good tune.
    I decreased my Learned Compensation Limits to 2% in the idle area (10% elsewhere). My Closed Loop Compensation Limits are 20% or less.
    When the Learn Table values stop making significant changes, the ECU is finished self-tuning. You can then Transfer Learning To Base,
    which then allows you to blend the Fuel Graph so it's smooth.
    http://forums.holley.com/showthread....7370#post47370 (Learn Table - Read this thread, especially posts #2, #6 & #11.)
    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.

  9. #19

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    If it's running well in Open Loop, I would turn off Closed Loop and let it warm up. In the datalog, it seems to be idling nicely in Open Loop, with a reasonable AFR, but right when it kicks into Closed Loop, the CL Comp goes through the roof and then it dies. Andrew

  10. #20

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    Update 9/7: I changed the following in the tune:
    --Increased fuel +20% across all cylinders.
    --Increased Closed Loop & Learn Compensation Limits to +100%/-100%.
    --Changed Closed Loop Advance Speed to 1.

    Datalogs:
    1. Config as stated above (WBO2 sensor was still heating first 5 seconds of datalog.)
    2. Changed Closed Loop Advance Speed to 5 (to see what would happen).
    3. Changed Closed Loop Advanced Speed back to 1.
    4. Disabled Closed Loop completely (did not seem to help as it still stalled after approximately 9 secs).

    Not much has changed other than a very lean initial startup AFR. A few common denominators I've noticed across these datalogs:
    --Approx 9 seconds into engine running that's when AFR's go out of whack and engine struggles to stay running.
    --My Estimated VE values appear to be very high across the board, averaging over 100% at this RPM range. Does this tell us anything?

    Using the Base Fuel Table as a reference, it looks like I should be in the 70-75% range for the MAP readings of 35-40 kPa that I'm seeing. (I apologize as I'm still learning about VE.) Thank you for all of your help!
    PM Logs.zip

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