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Re: Lash in the distributor drive [Re: INTMD8] #3047025
06/01/22 11:31 AM
06/01/22 11:31 AM
Joined: Jan 2003
Posts: 3,021
Erda, UT
67Charger Offline OP
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67Charger  Offline OP
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Erda, UT
Originally Posted by INTMD8
I understand you're thinking that it's stack up tolerances (and may be), just saying I wouldn't rule out the current distributor/ignition system as it seems that's a common issue observed among Pro Flo efi users.


The measurements I posted this morning nearly eliminate it being strictly mechanical. The lash only accounts for 6° total timing movement. RFI and the MSD Digital 6+ are the prime suspects currently.


11.33 @ 118.46 on motor
10.75 @ 125.35 w/ a little spray
Now, high Speed Open Road Racing - Silver State Classic Challenge, Nevada Open Road Challenge, Big Bend Open Road Race
Re: Lash in the distributor drive [Re: 67Charger] #3047138
06/01/22 04:12 PM
06/01/22 04:12 PM
Joined: Jan 2003
Posts: 3,021
Erda, UT
67Charger Offline OP
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67Charger  Offline OP
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As luck would have it, I checked the ProFlo instructions and the ECU will directly run an MSD Baster 2 without an ignition box. That will make that part of the troubleshooting easier anyway. Also means I should fab up a sub-harness to keep in the box of spares along with the Blaster 2 in case the next CDI box kicks the bucket.


11.33 @ 118.46 on motor
10.75 @ 125.35 w/ a little spray
Now, high Speed Open Road Racing - Silver State Classic Challenge, Nevada Open Road Challenge, Big Bend Open Road Race
Re: Lash in the distributor drive [Re: 67Charger] #3047139
06/01/22 04:16 PM
06/01/22 04:16 PM
Joined: May 2003
Posts: 6,335
Downtown Roebuck Ont
Twostick Offline
Still wishing...
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Still wishing...

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Downtown Roebuck Ont
Originally Posted by 67Charger
Originally Posted by INTMD8
Originally Posted by 67Charger
As stated, the problem was present with the MP distributor before that, both when it ran the megasquirt and also carbed with a MSD Digital-6. It was terrible enough that I went to the 36-1 and just used the distributor for distribution.


Right, so as stated, it was a completely different distributor and ignition system.


Close. Multiple distributors (stock, MP (both with advance and locked out for EFI), Edelbrock), multiple ECU's (Megasquirt-2/ProFlo-4) or direct feed from distributor pickup to ignition box (carb'ed), including reversing the p/u wires, but ALWAYS the same Digital 6.


I think you may have found the culprit. Anything else in the driveway you can test that box on? If you get the same results, it's the box. Assuming box is wired EXACTLY as instructed? Digital stuff is pretty sensitive to things like ground differentials and voltage drops/spikes etc.

I've seen it on a 6AL where somebody wired the main 12v source to the closest available instead of directly to the battery like the instructions dictated. It would NOT fire. Hooked + & - direct to the battery, vrooom!

Kevin

Re: Lash in the distributor drive [Re: Twostick] #3047147
06/01/22 04:46 PM
06/01/22 04:46 PM
Joined: Jan 2003
Posts: 3,021
Erda, UT
67Charger Offline OP
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Only other thing I have handy right now is my '81 F100 with the ole 300 straight 6. It's a Duraspark 2 ignition, so the wring would be a little diffferent, but it may still show wonky. Worth a shot.

As far as wiring the power source goes, the Digital 6 is currently tied to the 2/0 12V+ cable coming from the trunk from the battery cutoff at the under-dash starter solenoid (1st stop, and hub for 12V distribution). Ground is to the 2/0 12V- cable common Ground stud also near the starter solenoid. Alternator charge cable (4 AWG) goes all the way back to the battery terminal in the trunk. Since the battery powers the fuse panels through the cutoff, the alt cannot keep the engine running after the kill is thrown.

Last edited by 67Charger; 06/01/22 05:04 PM.

11.33 @ 118.46 on motor
10.75 @ 125.35 w/ a little spray
Now, high Speed Open Road Racing - Silver State Classic Challenge, Nevada Open Road Challenge, Big Bend Open Road Race
Re: Lash in the distributor drive [Re: 67Charger] #3052153
06/21/22 10:40 AM
06/21/22 10:40 AM
Joined: Jan 2003
Posts: 3,021
Erda, UT
67Charger Offline OP
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67Charger  Offline OP
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Erda, UT
Found another source of movement... The housing itself has loosened internally so the upper half could shake and rotate. The pickup has actually left a mark on the reluctor from contact. I made a pencil line on the housing then rotated it to show how much it moved.

20220617_045046.jpg20220617_045222.jpg

11.33 @ 118.46 on motor
10.75 @ 125.35 w/ a little spray
Now, high Speed Open Road Racing - Silver State Classic Challenge, Nevada Open Road Challenge, Big Bend Open Road Race
Re: Lash in the distributor drive [Re: 67Charger] #3052188
06/21/22 01:59 PM
06/21/22 01:59 PM
Joined: Sep 2003
Posts: 16,480
north of coder
moparx Offline
"Butt Crack Bob"
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north of coder
good catch. up
beer

Re: Lash in the distributor drive [Re: 67Charger] #3052215
06/21/22 03:47 PM
06/21/22 03:47 PM
Joined: May 2019
Posts: 4,583
nowhere
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Originally Posted by 67Charger
Only other thing I have handy right now is my '81 F100 with the ole 300 straight 6. It's a Duraspark 2 ignition, so the wring would be a little diffferent, but it may still show wonky. Worth a shot.

As far as wiring the power source goes, the Digital 6 is currently tied to the 2/0 12V+ cable coming from the trunk from the battery cutoff at the under-dash starter solenoid (1st stop, and hub for 12V distribution). Ground is to the 2/0 12V- cable common Ground stud also near the starter solenoid. Alternator charge cable (4 AWG) goes all the way back to the battery terminal in the trunk. Since the battery powers the fuse panels through the cutoff, the alt cannot keep the engine running after the kill is thrown.


Those cables are great antenna for picking up any stray EMI out there.

If you have on O'scope or access to one it'd be interesting to see what kind of noise is on your power and ground feeds to the ECU. Also the feed from the pickup inside the distributor. What type of plug wires are you running? Solid core are great radiators of EMI. Which may be why the 36-1 wheel cured the issue, far enough away from the noise source. Computers don't know what to do with noise being fed into it.

One simple way to cancel out noise is to use a twisted pair of wires.

Re: Lash in the distributor drive [Re: Sniper] #3052237
06/21/22 07:12 PM
06/21/22 07:12 PM
Joined: Jan 2005
Posts: 2,506
Milwaukee WI
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TRENDZ Offline
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Milwaukee WI
Doesn’t Edelbrock use “EFI Technologies” ECU? If they still do, you can unlock it and use any trigger system you want, including the previous 36-1 you were using.
I would never suggest using a distributor to supply a signal to your efi.


"use it 'till it breaks, replace as needed"
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