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Thread: Cold Start Issue

  1. #21
    Join Date
    Feb 2020
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    Wheeling, WV
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    1,454

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    You have electrical gremlins in the form of EMI/RFI, evident by the negative time stamps on the datalog. All the overlapping & squiggles is the ECU resetting while the engine is running or trying to run.

  2. #22

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    Both datalogs show resets so the gremlins have returned. No further changes should be made until you get the EMI/RFI solved. Tuning changes beyond what we've suggested can't be properly evaluated.

  3. #23

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    OK, I was wondering if that might be going on. I'm not even sure where to start. None of the Sniper wiring is close to any high voltage line. All of the ignition components are new. Positive & negative are directly connected to the battery terminals.

  4. #24

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    So after reading through https://www.efisystempro.com/efi-pro...r-rfi-problems I had some thoughts:
    - Alternator - It looks like I could use a new one anyway where the rebuilt, stock, 65 amp externally regulated alternator doesn't produce much at idle and was suggested earlier in this thread. I've looked at a few that are available for my application and not surprisingly, none of the descriptions mention anything about RFI or whether they're compatible with sensitive electronics. Is there something I should be looking for on these?

    - Wiring - All of my wiring meets the "Do's & Don'ts". I'll check all of the plug wire boots for proper fit & grease. Plug wires are new, 9mm, wire wound, low resistance and the plugs are new, copper gapped at 0.035". I'll do the lightning test when I get a chance. I removed all unused wires from the harnesses. I'm running the HyperSpark distributor. All other wiring is away from any plug/coil wiring. Ignition and Sniper battery wires are directly connected to the battery terminals.

    - Grounds - I have solid grounds from battery to engine, battery to chassis and battery to body. I'll double check the connection points.

    - When I first started the engine, I let run and warmup while performing all of the necessary checks with the Sniper. I got to the point where I wanted to take it for a short run down the road. So I went to close the hood and about 6" before closed the engine died. I opened the hood, started it again and went to close the hood and it died again. There isn't any wiring or anything obstructing the hood from closing and at the time, thought it very strange, but wasn't thinking about RFI. It has run without issue at least some times since then as seen in the first datalog files that I uploaded. Based on the way it has run (sometimes pretty good and other times not good without changing anything so I'm going to assume that it has to do with RFI), it seems that I get RFI when the engine is hot (or it just gets worse). Anything else anyone has for suggestions, I'm all ears! Thanks!
    Oh, Happy Independence Day!
    Last edited by Timbick; 07-04-2021 at 07:05 AM.

  5. #25
    Join Date
    Feb 2020
    Location
    Wheeling, WV
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    1,454

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    To see proof of the culprit takes an oscilloscope or the cheap less visual proof is a transistor radio. Often times the problem is as much about routing of the sensitive input/output cables and not so much about keeping them as far away from everything as possible.
    When it comes to the alternator, I'm not going to get into the reason why right now, but get one that would've come stock on an EFI car. Any of the CS & later GM versions are approved. The older SI versions will work when they're in very good condition, but it's like rolling the dice on the older versions. More later...

  6. #26

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    A few thoughts: RFI
    - Where's your pink trigger wire connected? That wire is a big culprit to RFI/EMI. Best practice is to have it wired through a relay with clean battery power. If you're working on an older muscle car, wiring the pink trigger to the fuse panel is asking for trouble. If you don't have it on a relay, that's the absolute first thing I'd try.
    - Is your alternator a DN style? If you upgrade the alternator go right to a CS130 if a Chevy, but a quality 12SI will work as well. This is a good idea eventually, but I'd try other things first.
    - Some may disagree with me, but every time I put dielectric grease on my spark plug boots I get EMI issues. I then clean the grease out and the issue goes away. You may want to try that.

    Cold Start issue:
    - You are using the "Wizard" A/F Ratio Offset, which is waaaaay too rich for every application and will cause it to run poorly when cold starting. In the Temperature Enrichment section of the fuel tables, go to the A/F Ratio Offset and make the following changes: Set the value to −0.6 at the coldest setting (-40°F in yours) the set to 0 at 70°F and hotter. Next adjust the chart so it is a smooth line from -40 to + 70.

    - Have you changed the plugs? The Sniper Wizard settings, especially the Offset, will foul your plugs in not time. I went through a couple of sets when dialing things in.
    - Give it more timing at idle. Try 20° and don't be afraid to go higher if needed.
    Last edited by gregs69rs; 07-04-2021 at 09:22 AM.

  7. #27

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    Thank you, I'll look into these ideas. It's a Ford by the way in regards to alternators. Also, I was talking to a friend who has a lot of experience building cars and airplanes, though not with EFI and he was wondering if using capacitors for RFI filters would be of any help. He suggested the fuel pump and alternator as potential candidates for this. The fuel pump I have is the one provided in the kit from Holley (I believe it's a Walbro). I currently have the pink wire connected to the line where the former Duraspark II ignition was powered, it seemed like the cleanest location for run & start +12V power. I've tried to borrow an oscilloscope, no luck yet. Thanks again!

  8. #28
    Join Date
    Dec 2009
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    Connecticut
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    29,073

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    Quote Originally Posted by Timbick View Post
    It's a Ford by the way in regards to alternators.
    Since it's a Ford, use a Ford 3G alternator. Best alternator I've ever used. The 1-wire alternator was the worst I ever owned. The Ford 3G alternator is an incredible improvement at idle & higher RPM. Ford applications should use a Ford 3G alternator. There's no better alternator for a Ford.
    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, Holley Dominator MPFI & DIS, 36-1 crank trigger, 1x cam sync, 200A 3G alternator, Optima Red battery, R134a A/C, 100HP progressive dry direct-port NOS, Spal dual 12" fans, Frostbite 3-core 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, BMR upper & lower torque box reinforcements, LenTech Strip Terminator wide-ratio AOD, 3000 RPM converter, B&M Hammer shifter, Stifflers trans crossmember & driveshaft safety loop, 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. #29

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    Thanks. I'm looking into the Ford 3G conversion, looks pretty simple. In the meantime, I worked on this Config File while taking into account all of the great help you guys have given, and some tunes that I found while looking around. I haven't loaded it yet, (not until I fix the RFI issues), but I was wondering what your opinions are with this. Thanks again!
    Attached Files Attached Files

  10. #30

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    You're making a lot of changes and you may find it difficult to determine what made it better or worse. Correct the EMI/RFI and run it with the last tune that was developed first. Things were leaned out and with ECU Learning and by Transferring Learning To Base, you can then make better decisions on future mods. As mentioned earlier, changes to Acceleration Enrichment and starting should only be done after a solid base tune is achieved and I'm not sure you're there yet.

    The alternator stands out as an issue, but it may not be the sole cause. Get a good charge on the battery and remove the alternator belt (whether it drives the water pump or not) and take a datalog when you start it. If it resets then you know that the problem is likely ignition. If it seems to run OK before it starts getting hot, then the alternator may be the one issue.

    If you're into some fun, Ford 3G alternators are usually readily available at pick & pulls. In addition to the Ford 3G alternator you can grab the wiring that takes you all the way back to the battery with fusible links. There are 90ish amp & 130 amp versions, and if you don't need the capacity, the 90 amp version will work well and is less likely to chirp the belt(s) during startup. I bought a junkyard 3G with the intention of using it as a core and I'm still running it three years later.

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