How to tell if a distributor pickup is good?
#497010
10/14/09 01:53 PM
10/14/09 01:53 PM
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Joined: Nov 2006
Posts: 2,255
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furious70
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I've lost spark in the Fury. It's got FAST efi which also controls the spark.
Lean burn dizzy connects to the ECU
ECU uses the white trigger wire to talk to the MSD
MSD fires an accel supercoil
I have power to the MSD box and the ECU during both start and run (verified)
When I use my test light on the white trigger wire, I hear either the pickup or the coil making noise and a test spark plug will arc. I get no spark cranking the engine over or when I release the key to the run pos.
Since I get spark to the plug when I ground the trigger circuit, is it safe to assume the problem is in the trigger portion of the circuit (i.e. when I short the trigger the MSD box, coil, wires seem to do their jobs).
If so, how do I test the guts of the dizzy?
70 Sport Fury
68 Charger
69 Coronet
72 RR
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Re: How to tell if a distributor pickup is good?
[Re: Crizila]
#497014
10/14/09 02:36 PM
10/14/09 02:36 PM
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Joined: Nov 2006
Posts: 2,255
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furious70
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I have a digital voltmeter, so no needle. I'm better with my test light than meter, which dial selection is going to be the ohmmeter, the infinity symbol?
I may have another pickup, I had another lean burn with a bent shaft, if not, I'll take you up on the offer.
I'm hoping it's something like this and not something wrong with the ECU.
70 Sport Fury
68 Charger
69 Coronet
72 RR
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Re: How to tell if a distributor pickup is good?
[Re: furious70]
#497015
10/14/09 02:38 PM
10/14/09 02:38 PM
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Joined: Jun 2008
Posts: 1,822
Colorado
denfireguy
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Posts: 1,822
Colorado
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Quote:
I've lost spark in the Fury. It's got FAST efi which also controls the spark.
Lean burn dizzy connects to the ECU
ECU uses the white trigger wire to talk to the MSD
MSD fires an accel supercoil
I have power to the MSD box and the ECU during both start and run (verified)
When I use my test light on the white trigger wire, I hear either the pickup or the coil making noise and a test spark plug will arc. I get no spark cranking the engine over or when I release the key to the run pos.
Since I get spark to the plug when I ground the trigger circuit, is it safe to assume the problem is in the trigger portion of the circuit (i.e. when I short the trigger the MSD box, coil, wires seem to do their jobs).
If so, how do I test the guts of the dizzy?
If grounding the coil causes the plug to fire, you definitely have an issue with the primary side. If you have a scope, putting the probe on the distributor trigger wire and look for the pulses. Without one, check DC resistance for the 150-900 ohms on the reluctor pickup coil. After that, you are reduced to substituting parts. My guess and only a guess is the MSD box.
Craig
2014 Ram 1500 Laramie, 73 Cuda
Previous mopars: 62 Valiant, 65 Fury III, 68 Fury III, 72 Satellite, 74 Satellite, 89 Acclaim, 98 Caravan, 2003 Durango
Only previous Non-Mopar: Schwinn Tornado
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Re: How to tell if a distributor pickup is good?
[Re: Crizila]
#497017
10/14/09 03:12 PM
10/14/09 03:12 PM
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Joined: Nov 2006
Posts: 2,255
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furious70
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I've had the no start trouble a couple times over the summer while I've been learning the EFI, and I'm pretty sure one time grounding the trigger with the test light 'fixed' it, and a 2nd time just a couple weeks ago disconnecting the ECU from the Battery and reconnecting fixed it. Don't know that that info helps in the debug, but it's what I've been dealing with.
70 Sport Fury
68 Charger
69 Coronet
72 RR
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Re: How to tell if a distributor pickup is good?
[Re: Crizila]
#497018
10/14/09 03:14 PM
10/14/09 03:14 PM
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Anonymous
Unregistered
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Anonymous
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best way i found how to tell if the pick-up is bad is just to replace it.
there cheap enuff, it'll tell you right away, and saves you one gynormous headache.
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Re: How to tell if a distributor pickup is good?
#497019
10/14/09 05:07 PM
10/14/09 05:07 PM
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Joined: Nov 2006
Posts: 2,255
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furious70
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forgot to put in the original post that I have no power to + or - on the coil during start or run positions on the key.
I'm running a 1 wire alt and I've customized the start and run circuits out from under the dash to feed the ECU, MSD, and fuel pump relay trigger.
70 Sport Fury
68 Charger
69 Coronet
72 RR
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Re: How to tell if a distributor pickup is good?
[Re: furious70]
#497020
10/14/09 10:00 PM
10/14/09 10:00 PM
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Joined: Jun 2008
Posts: 1,822
Colorado
denfireguy
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Colorado
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Quote:
forgot to put in the original post that I have no power to + or - on the coil during start or run positions on the key.
I'm running a 1 wire alt and I've customized the start and run circuits out from under the dash to feed the ECU, MSD, and fuel pump relay trigger.
Then there was no way that you got a spark out of it. There should be at least 6 volts there to generate a spark grounding the coil.
2014 Ram 1500 Laramie, 73 Cuda
Previous mopars: 62 Valiant, 65 Fury III, 68 Fury III, 72 Satellite, 74 Satellite, 89 Acclaim, 98 Caravan, 2003 Durango
Only previous Non-Mopar: Schwinn Tornado
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Re: How to tell if a distributor pickup is good?
[Re: denfireguy]
#497021
10/14/09 10:47 PM
10/14/09 10:47 PM
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Joined: Jan 2003
Posts: 7,490
Minnesota
Hemi_Joel
master
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master
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Posts: 7,490
Minnesota
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Disconect the 2 wires that go from the fast efi to the magnetic pickup in the dist. Disconnect the coil wire from the center of the distributor cap and plug a sparkplug into it. (with the base grounded of course) Turn on the ignition switch. Use a short jumper wire to connect the 2 disconnected wires going to the FAST EFI. As you connect and disconnect the jumper, a spark should occur at the spark plug. If it does, then your pickup coil in the dist is probably bad. If it does not, something is wrong in the FAST system. You have already verified that the MSD and the Coil are good. Like someone else said, you can put your digital ohm meter across the two wire from the dist pickup coil. Turn the dist and the ohm reading should pulsate each time the tip of the star passes the coil. Good luck. 
[img]http://i.imgur.com/boeexFms.jpg[/img]31 Plymouth Coupe, 392 Hemi, T56 magnum RS23J71 RS27J77 RP23J71 RO23J71 WM21J8A I don't regret the things I've done. I only regret the things I didn't do. "Wise men talk because they have something to say; fools because they have to say something. ~ Plato"
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Re: How to tell if a distributor pickup is good?
[Re: Hemi_Joel]
#497022
10/20/09 09:04 AM
10/20/09 09:04 AM
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Joined: Nov 2006
Posts: 2,255
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furious70
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I see 200rpm when cranking in the efi dashboard, but my conventional tach, hooked to the msd tach output, is completely dead, no bouncing at all.
This is telling me the dizzy is ok and either msd or ecu have trouble I think.
Is the next step to substitute the msd box? I grabbed another used 6a box from the shop last weekend. Is there a way to test the white trigger wire my ecu is sending pulses to the msd on? (the points trigger wire)
70 Sport Fury
68 Charger
69 Coronet
72 RR
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Same info in the Chrysler manual Jeremy. If you are using an analog ohm meter, you can plug the leads in to the pig tail and as you spin the engine over, the needle will wiggle as the reluctor passes the coil. Think I still got an old lean burn dist. out of Mary's 300 if you wanna try swaping pick-ups.