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Thread: Engine Randomly Dying

  1. #1

    Default Engine Randomly Dying

    I'm having a difficult to diagnose intermittent issue with what I believe to ignition/electrical. I have Terminator EFI on an AMC 360 with an Aeromotive fuel pump and regulator. I was running a mechanical MSD distributor with MSD 6A and Blaster coil and the car started shutting off on me randomly. It would fire right up again. Then it would take a while to fire up. Then it started randomly losing power before dying. Obviously a progressive issue. I replaced the coil and it seemed to clear it up, but it started again soon a little less frequently. Finally, it died and wouldn't start again. This time I noticed the WBO2 sensor pegged lean, so I replaced my cap and rotor, coil again, and ran Open Loop from a clean fuel table to get home. It died several times on the way home generally after a heavy throttle run.

    In the interim, I've decided to just throw parts at the ignition system and hope for the best. I've installed a HyperSpark distributor, CDI box, coil plus new wires and an WBO2 sensor. I found the MSD wires I replaced to vary wildly in resistance. They were anywhere from 60 Ohms/ft to over 300. Spec is 50. I cleaned the IAC valve and injectors. I went through all of the vehicle wiring again and added a beefier ground from engine to chassis and additional chassis ground directly from the battery. The CDI box and ECU power and ground are straight to battery. I have a fused 12V switched junction bar for all of the switched power.

    Today, I adjusted the spark config, started up the car, and synced the timing. New WBO2 sensor seems to be working fine. After warming up, I took a drive. The car seemed to be running OK. I took a short 3/4 throttle run and coasted for bit then the car died once again. Afterwards, it would crank and fire, then die again immediately. I could feather the throttle and keep it going for a second or two then it'd die again. Eventually it fired up and after a few revs, it settled back to an idle and I was able to ease it the mile back home.

    NOW then, I have one more thing to sort out before testing again. The coil wire included in the Accel Super Stock 8mm wire set I used was too short to reach the fender where I mounted the coil, so I reused the best length of the MSD wires I was replacing that tested at or actually a little under the 50 Ohms/ft spec for the wire. I just noticed before typing this that it has a very slight nick in the outer jacket though. I have a single 60' Accel Super Stock 8mm wire on order to replace that.

    Barring that one wire being the culprit, what else can I look for that has remained common from before to now? Ah, forgot to mention I replaced the worn out Yellow Top battery that wouldn't hold a charge with a brand new Red Top. The 10SI alternator I have is functioning well also. And unfortunately, I wasn't datalogging when it died today. I do believe I recall datalogging a few months ago when I was having the issue initially and there was no indication there of why it had died. It was all fine one second then deadlines the next.

  2. #2
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    Ensure all of this is correct: http://forums.holley.com/showthread....ents-Read-This (Initial Checks & Adjustments - Read Steps #1-#6!)
    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, 232°-244° duration/.623" lift/114° LSA camshaft, 11.8:1 comp, TFS R-Series FTI ported intake, 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, S&W subframe connectors, LenTech Strip Terminator wide-ratio AOD/3000 RPM converter, 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 MT tires.

  3. #3

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    Thanks Danny. Everything checks out except that my HyperSpark distributor (Hall-Effect crank input) is powered by 12V from pin E on the ignition connector. Additionally, my Terminator harness did not have the loose points output wire, so I moved the unused cam input wire (pin B on ignition connector) from A22 (cam input) on P1A to A6 (points out). The Holley wiring manual specifies 18 AWG for points out and the cam input wire I used is 22 gauge. Perhaps it's not carrying a strong enough signal to ground the coil through the HyperSpark CDI box effectively and under ignition system load, is causing the engine to die? Seems a little far-fetched maybe.

    I'm going to check resistance in the new wires I made up last night and I'll get that replacement coil ignition wire in a few days.

  4. #4

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    I'll need to get a hold of some SuperSeal 1.0 terminal pins to try moving the 12V power to the HyperSpark Hall-Effect sensor to clean ECU power. Is there any source for SuperSeal pins for less than the minimum purchase amount required on the Tyco website? In addition, should I try changing my Ignition Parameters from Digital Rising to Digital Falling? And if I do, should I just adjust with the timing light to sync things back up? It seems I'd only be off a few degrees with the change. It should be easily visible cranking with the injectors unplugged and/or should even idle for me to set to my 25° at idle from my Base Timing Table.

    The curious thing is still that this was happening before I was controlling timing with the Holley ECU. Unless I'm having similar symptoms with two different issues! The old coil wire is still suspect. It's within resistance specs for that wire, but who knows if it's degrading under electrical load or heat.
    Last edited by Red20; 03-23-2020 at 12:51 PM.

  5. #5
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    Quote Originally Posted by Red20 View Post
    I'll need to get a hold of some SuperSeal 1.0 terminal pins to try moving the 12V power to the HyperSpark Hall-Effect sensor to clean ECU power. Is there any source for SuperSeal pins for less than the minimum purchase amount required on the Tyco website?
    https://www.holley.com/brands/holley...ins_and_seals/ (Holley EFI Wiring Shop)

    In addition, should I try changing my Ignition Parameters from Digital Rising to Digital Falling?
    I never use Digital Rising, although it's probably not your problem.
    https://forums.holley.com/showthread...163#post225163 (Related Forum Thread)

    And if I do, should I just adjust with the timing light to sync things back up? It seems I'd only be off a few degrees with the change. It should be easily visible cranking with the injectors unplugged and/or should even idle for me to set to my 25° at idle from my Base Timing Table.
    Yes, timing will need to be slightly resynchronized.

    The curious thing is still that this was happening before I was controlling timing with the Holley ECU. Unless I'm having similar symptoms with two different issues! The old coil wire is still suspect. It's within resistance specs for that wire, but who knows if it's degrading under electrical load or heat.
    You might as well replace it.
    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, 232°-244° duration/.623" lift/114° LSA camshaft, 11.8:1 comp, TFS R-Series FTI ported intake, 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, S&W subframe connectors, LenTech Strip Terminator wide-ratio AOD/3000 RPM converter, 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 MT tires.

  6. #6

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    I measured resistance in the new wires I built. Summit Racing lists the 8mm Accel Super Stock wires as 500 Ohm/ft. Mine were measuring a factor of 10 higher. Looking at the back of the box, they're actually 3000-7000 Ohm/ft. So that makes sense. Now I'm wondering if they're getting hot or leaking with so much resistance. These wires are extremely common though and used in many applications. Got me scratching my head. I'll get that new coil wire Thursday and go for a drive to datalog. I'll get a System Log as well. I can do both at the same time, yes?

  7. #7
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    Quote Originally Posted by Red20 View Post
    ...and go for a drive to datalog. I'll get a System Log as well. I can do both at the same time, yes?
    Yes, read 4th paragraph under "NOTES": http://forums.holley.com/showthread....s-amp-Datalogs (Datalog & System Log 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, 232°-244° duration/.623" lift/114° LSA camshaft, 11.8:1 comp, TFS R-Series FTI ported intake, 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, S&W subframe connectors, LenTech Strip Terminator wide-ratio AOD/3000 RPM converter, 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 MT tires.

  8. #8

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    Quote Originally Posted by Danny Cabral View Post
    Yes, read 4th paragraph under "NOTES": http://forums.holley.com/showthread....s-amp-Datalogs (Datalog & System Log Information)
    Thanks, Danny. Do you think 5,000 Ohm/ft ignition wires could be an issue in my case?

  9. #9
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    If that's what they're supposed to be, then they shouldn't be a problem.

    You'll have to record & review a datalog of this occurrence. An EFI system won't run without a crank sensor signal. If a regular datalog
    indicates an "RPM Error" when scrolling through the problem area, then it's time for a System Log to confirm if the sensor flatlines.

    Record a System Log to verify crank & cam sensor signals. Check mark the "RPM", "Crank" & "Cam" channels. Look for a uniform,
    uninterrupted crank or cam sensor signal pattern. The crank or cam sensor signal should never flatline (no pulse) or indicate an
    RPM "Error" anywhere. Also, fully charge the battery and ensure the engine is cranking fast enough, at least 100+ RPM. Another
    common issue, is trying to analyze a compressed view of a long System Log. Zoom In for detail - click & hold at one point of the
    datalog, and drag & release to another point nearby. It's best to record short System Logs/Datalogs that capture the problem.
    http://forums.holley.com/showthread....s-amp-Datalogs (Datalog & System Log Information)

    Originally Posted by Danny Cabral
    Quick Datalogger Information:
    Always provide data, not just symptoms. Is the AFR & ignition timing optimized? Overlay the datalog onto your Global File.
    Ensure the Target A/F Ratio table is properly programmed for your engine. Ensure the ECU is "Learning" (Learn Table LINK).
    Scroll through the datalog to the problem area. Then look exactly where this happens on the Base Fuel & Timing Tables. Scrutinize:
    RPM, MAP, MAT, TPS, CTS, IAC, Target AFR, AFR Left, CL Comp, Ignition Timing, Duty Cycle, Fuel Flow, Fuel Pressure & Battery.

    Using the Holley EFI software (LINK), look at where the live cursor moves to during this occurrence, and
    manually tune that area of the Base Fuel Table (enrich or lean) & Base Timing Table (optimize ignition timing).


    I find the most helpful datalog function, is overlaying the datalog on your Global File.
    I'm in the habit of using the datalog Overlay feature every time I review a datalog.
    Click on "Datalog" (on the top Toolbar), "Activate Overlay", then "Open Data Log".
    You can literally "playback" a recorded event, and watch it as it happened on any screen.
    Minimize (shrink) the datalog window, and move it to the bottom of any Global File screen.
    Then click & scroll anywhere on the datalog, and watch it playback on your Global File (EFI software).
    http://documents.holley.com/techlibr...9r10543rev.pdf (Holley EFI Datalogger Instructions)
    https://forums.holley.com/showthread...s-amp-Datalogs (Datalog & System Log Information - Read "NOTES")
    https://www.youtube.com/watch?v=iqHO...C6FEA0BB99AF17 (How To Record & Email A Datalog)
    https://www.youtube.com/watch?v=q7OZUXLRS1Q (How To Record A System Log & Diagnose A No-Start Condition)
    https://forums.holley.com/showthread...7531#post77531 (Closed Loop Datalog Tuning - Posts #2, #4 & #6)
    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, 232°-244° duration/.623" lift/114° LSA camshaft, 11.8:1 comp, TFS R-Series FTI ported intake, 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, S&W subframe connectors, LenTech Strip Terminator wide-ratio AOD/3000 RPM converter, 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 MT tires.

  10. #10

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    And the problem was...MAP sensor. Yep, the MAP sensor is on the fritz. Now initially, I was having misfires due to degrade plugs and that fried the WBO2 sensor. But the MAP sensor was going also and would randomly and suddenly malfunction, killing the car. It would fire back up on startup fueling, but immediately die. I thought it was the plug and/or wiring initially, because wiggling the plug and watching the sensor readout would result in it going from a low error to showing a reading and back again. Troubleshooting revealed the wiring to be fine, however. Flexing the body of the MAP sensor by wiggling on the plug causes something internally to connect and disconnect. I'll confirm further once I receive a replacement, but that's where I'm at for diagnostics for now.

    Looking over a System Log after switching to timing control with the HypersSpark distributor was a reassuring activity for sure. It was good to see the crank sensor working properly.

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