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Thread: Starts, may or may not run for a few minutes or less, and stall.

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  1. #1

    Default Starts, may or may not run for a few minutes or less, and stall.

    I just finished a Sniper EFI install. I'm using a CD box and have it wired that way, as well as selected that way in the Wizard. Pink wire is ignition hot. 392 Hemi with MSD billet distributor. A carb works so I know the CD box, distributor, etc., all work.

    I get a start and sometimes it dies right away after letting off the start. Other times it will idle for a few seconds and die, and other times it last longer especially if I throttle it a bit and hold it steady. The RPM are way high at start and any time it idles. I have set it for a much larger displacement engine as well as a smaller engine to no avail. I've moved the idle screw to open the plates and backed it off to no avail. I've checked, checked and rechecked wiring. I've moved the spark plug wires and coil away as much as possible to no avail.

    Spark, rotation, air, compression are all there. Fuel is there during prime and seems to burn up right away and not be replaced unless I push the throttle linkage. I've done all the reading I could find concerning this thing and nothing makes the problem any better. Vacuum lines are plugged or used, so it's not a leak. Again carb works so I know vacuum lines are good. Did a firmware update also per the Holley instruction that all went smoothly.

    I removed this heap for now as it doesn't work. It took all night to be able to post here. (Ranting but that was frustrating when I'm looking for ideas, eight hour wait time). I have covered all the bases I can think of and I'm left to believe this thing is faulty.

    I may have missed a few things I tried, but does anyone have further ideas or suggestions? It's just super frustrating getting a new not cheap unit that is supposed to be self Learning and fairly problem free, but so far its just the opposite. This thing is useless at the moment.

  2. #2
    Join Date
    Dec 2009
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    Well how much lb/hr fuel (click "Conversion") is in the idle area when it runs momentarily? Also, it's often necessary to turn the ignition key on, wait for the WBO2 sensor to display AFR, then start the datalogger & engine. This allows you to determine if the engine AFR is excessively rich or lean. Is it stalling due to a rich or lean condition?
    https://forums.holley.com/showthread...869#post218869 (Related Forum Post)
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: 385" SBF, Dart SHP 8.2 block, TFS TW 11R 205 heads, 11.8:1 comp, TFS R-Series intake, Dominator MPFI & DIS, 36-1 crank trigger/1x cam sync, 160A 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, 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. #3

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    Here's the other frustrating problem. Where in the instructions does it say any of that? It's a crap shoot searching the web for possibilities and problems other people encountered. Sorry I'm venting a bit, but I wasted many hours on it. So say it's rich or lean then what? Program a fuel map, curve, settings, etc? If that's a yes, this thing is going back. Had a Holley Commander 950 I had to program with a laptop while the car was being driven. Not doing that sort of thing again. Self Learning means self Learning, not me programming it so it can run. Forgot to mention I do have fuel pressure between the throttle body and pump. It reads a good consistent 60 psi.

  4. #4
    Join Date
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    Quote Originally Posted by 51coronet View Post
    Here's the other frustrating problem. Where in the instructions does it say any of that?
    http://documents.holley.com/199r11369.pdf (Holley Sniper EFI Troubleshooting Guide)
    We know the Sniper EFI functions properly, and the Sniper does exactly what it's told to do.
    Most Sniper EFI problems are installation or programming errors. This forum is full of them.

    Had a Holley Commander 950 I had to program with a laptop while the car was being driven. Not doing that sort of thing again.
    The Sniper EFI is much easier because it has a self-tuning fuel map (Learn Table), unlike the Commander 950 EFI.

    Self Learning means self Learning not me programming it so it can run.
    No, you still have to properly program the initial parameters, and select the proper base calibration.

    Forgot to mention I do have fuel pressure between the throttle body and pump. It reads a good consistent 60 psi.
    Does the Data Monitor display correct values for all the other sensor?
    https://forums.holley.com/showthread...2178#post92178 (Sniper EFI Troubleshooting & Technical Information)
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: 385" SBF, Dart SHP 8.2 block, TFS TW 11R 205 heads, 11.8:1 comp, TFS R-Series intake, Dominator MPFI & DIS, 36-1 crank trigger/1x cam sync, 160A 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, 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. #5

    Default

    Digging around online is not what I meant. Nothing came with this system to help diagnose without going online. Nothing technical was included.

    Base fuel map should keep it running even if its running sloppy which it runs nicely (just too many RPM) when it does run, but shortly shuts off. How sensitive is this with voltage fluctuations? I ask because sometimes it shuts off immediately after I stop cranking the starter. Seems like it doesn't like the changes in voltage caused by the starter being used and then not used. The other thing is when it runs longer it doesn't just sputter and die it straight shuts off with no warning. I have kept it running longer by holding the starter spinning with the engine running, but letting go has caused it to just die. Pink wire is hot the entire time no switching with pushbutton transmission setup. Key has no crank position just on and accessory. Pushbutton start is wired to starter relay. Pink wire is separate from this on its own key hot source which stays on no matter cranking or not. As long as the key is set to run it's hot.

    Am I chasing my tail here? These symptoms don't seem to fall into the typical "you did something wrong" category. How do you explain holding the starter on spinning then letting go the car shuts off? once in a while it stays running, but will shut off within 30 seconds give or take a few. The handheld gauge reads RPM correct then reads stall when it shuts off.

    Quote Originally Posted by andyf View Post
    You aren't providing enough information for anyone to help you. There are a ton of reasons why the engine would start & run for a few seconds and then turn off. Could be fuel flow, fuel pressure, wrong AFR, wrong timing, wrong firing order, various mechanical problems, etc. Could be an installation error, a programming error, a mechanical failure, etc. You'll have to narrow it down a bit before you'll get any help. Follow the instructions that came in the box. Turn the key on, look at the gauge panel on the handheld and see if they're all reading correctly. Proceed from there.
    Read: It runs with a carb. So that eliminates 99% of what you say. Gauges read correct. Try again. I followed instructions. Try again. Installation is correct per the vague instructions. Try again. If you read maybe you would understand that. I narrowed it down. Try again. Read everything before posting next time.

  6. #6

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    Must add that I'm NOT using any of the extra control features of the system. (Magnetic pickup is wired direct to CD ignition box then from there the Sniper is getting an RPM signal per the instructions) The troubleshooting flow charts don't apply since I can't get to 160°F engine temp. Engine needs to stay running for that to happen...SO I digress to my above posts. Note to anyone else that's inclined to point the finger at me, please read the conditions I described first. I'm not a rookie and I'm very electrically inclined. So with that said, save the finger pointing comments. I'm looking for suggestions and things to try based on what I have stated.

  7. #7

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    If you just want to argue that you did everything correctly and that it isn't your fault, then why did you bother posting a question here? Most Sniper EFI installation problems are user error. I'm guessing yours is too. Good luck with your install.

  8. #8

    Default

    You aren't providing enough information for anyone to help you. There are a ton of reasons why the engine would start & run for a few seconds and then turn off. Could be fuel flow, fuel pressure, wrong AFR, wrong timing, wrong firing order, various mechanical problems, etc. Could be an installation error, a programming error, a mechanical failure, etc. You'll have to narrow it down a bit before you'll get any help. Follow the instructions that came in the box. Turn the key on, look at the gauge panel on the handheld and see if they're all reading correctly. Proceed from there.

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