Re: '84 Chrysler 5th Avenue conversion from computer to ecu
[Re: dfixer]
#2430842
01/08/18 12:20 AM
01/08/18 12:20 AM
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Joined: Nov 2003
Posts: 36,041 Lincoln Nebraska
RapidRobert
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Circle Track
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with the black/yellow lead off of the coil neg pri terminal & jumping the threaded coil terminal to ground (tap tap tap) with a jumper you get no coil wire spark in run/crank? (& it sparks on the "break"). Not sure what is going on there/what we are missing BUT if it (coil wire) sparks when you drag the zigzag connector across the intake then the problem is STILL in the dist.
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Re: '84 Chrysler 5th Avenue conversion from computer to ecu
[Re: dfixer]
#2430906
01/08/18 03:40 AM
01/08/18 03:40 AM
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OK, this started because one day the car would crank but not start. I figure the computer has gone bad so I install the conversion kit. It runs great for a month then back to crank but no start. Looks like the pickup coil screw didn't do its job, so I reset the gap, it runs fine for 8 miles and then the next day back to crank but no start. So if dragging the zigzag connector across the intake causes the coil wire to spark, I presume that spark is coming from the ignition coil which means it is OK even if it will not spark when I ground the negative post on the coil itself.
Let me see if I have this right. The reluctor breaks the magnetic field inducing a voltage in the pickup coil, sending that pulse through the zigzag connector on pins 4 & 5 of the pentastar connector in the ECU, that in turn fires off a signal to the ignition coil, that induces a small voltage in a small winding to be a large voltage in the larger winding going into the coil wire to the top of the dist. cap and out the rotor to the spark plug and ignites the fuel. So in the simplest terms it is a three part system, distributor, ECU and ignition coil and when we ground the zigzag connector and it sparks we have taken the place of the distributor proving that the other two thirds of the system are working (even if I can't get the coil test to spark). Is that correct?
So if it is the dist., what is it in the dist.? The reluctor turns on the shaft and that is all it can do, the pickup coil or its wiring could be bad, the cap and/or rotor could be bad. Am I right with that list? What is the next approach? Do I change the cap, the rotor, the pickup coil? My old dist. had two pickup coils. Do I sub it using just the two conductor zigzag connector?
Though I have replaced the coil and replaced the computer with the conversion kit and I am still having the same problem I started with, am I overlooking something that didn't get replaced that could cause it not to crank? But why did it work so well for a month. . .and 8 miles?
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Re: '84 Chrysler 5th Avenue conversion from computer to ecu
[Re: dfixer]
#2431017
01/08/18 01:13 PM
01/08/18 01:13 PM
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Joined: Nov 2003
Posts: 36,041 Lincoln Nebraska
RapidRobert
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the reluctor tooth induces a slight AC voltage in the pickup coil & that "triggers" the ECU to unground the black/yellow wire from the coil neg pri terminal. the coil works opposite of other devices, it is being fed voltage & it sparks when the current is stopped & the magnetic field in that primary circuit collapses & induces a current in the secondary circuit (the large center post/wire). when you do the coil test you dont keep the coil neg primary terminal grounded like it sounded like you were saying (if I interpreted it right) but you tap tap the alligator clip to ground & it sparks when you lift it up off the intake (ungrounding it). OK, if dragging the pickup nub makes it spark in run and in crank with the ECU plugged in/everything else hooked up normal then all that is left is from the zigzag connector back to/including the pickup (electrically) & the gap (mechanically). You have provided excellent details but I feel I am inadvertently missing something. lets try this: repeat the zigzag dragging test BUT have a helper cranking the ign & see if the coil wire sparks.
live every 24 hour block of time like it's your last day on earth
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Re: '84 Chrysler 5th Avenue conversion from computer to ecu
[Re: dfixer]
#2431298
01/08/18 10:12 PM
01/08/18 10:12 PM
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RapidRobert
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lets do this: turn the crank CW with a 1&1/4" socket/breaker bar till the rotor tip is centered under the nearest dist cap plug wire terminal bulge. coil wire plugged in. pull the plug wire that the rotor tip is under & either put a spark plug in it & ground the plug or put a piece of metal up in the end of the plug wire boot & hold the metal end 1/4" from a ground with one hand & drag the pickup nub across the intake with your other hand & see if it sparks/or the plug gap sparks if you use a plug. try it with the key in "run" and pull the yellow wire off of the starter relay to disable the starter & have her hold the key to start as you again drag the zigzag tip across the intake & see what we get. If the "dragging" of the zigzag conector is makeing it spark then it has to be in the dist: pickup/zigzag connector a bit loose (the 2 female terminals in it)/rotor/wires/plugs cuz the pickup is what triggers the ECU & the dist distributes the fire to the 8 plug wires/plugs.
live every 24 hour block of time like it's your last day on earth
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Re: '84 Chrysler 5th Avenue conversion from computer to ecu
[Re: dfixer]
#2431830
01/09/18 09:25 PM
01/09/18 09:25 PM
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Joined: Nov 2003
Posts: 36,041 Lincoln Nebraska
RapidRobert
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lets keep the same stuff on there cuz it is functioning OK (bottom line is spark at the plugs & it is doing that). Tho we gotta figure out why it ain't sparking when it is turned over with the key cuz the brown wire (crank) circuit is getting powered when she turns the key to crank (cuz the dragging is makeing it spark) (with the starter disabled) but it will not spark while cranking & the only difference that I can see so far is that the dist is in effect doing the "dragging" & the zigzag is plugged back in & it ain't doing its job for some reason. So with everything plugged back in & her cranking it there is no spark at the plug(s)? it keeps point to the dist & if that 2 magnet dist has 2 "regular" zigzag connectors we may have to install that dist & use whichever pickup gives us the best phaseing. FIRST lets do this: repeat your last test with (2) changes: plug the starter relay yellow wire back in & have her crank it while you drag the (unhooked) pickup nub (same as before) across the intake & see if the coil wire and any plug wire is sparking. EDIT see if the coil wire sparks then plug it in the dist & see if the plug wires spark.
Last edited by RapidRobert; 01/10/18 02:10 AM.
live every 24 hour block of time like it's your last day on earth
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Re: '84 Chrysler 5th Avenue conversion from computer to ecu
[Re: dfixer]
#2432559
01/11/18 12:21 AM
01/11/18 12:21 AM
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RapidRobert
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everything is pointing to the dist. this other 2 zigzag dist, maybe it is time we try it (not permanent but just to pin it down). Does this dist have 2 zigzag plug ins/2 pickups/no vac or mech adv? with the 1&1/4 socket get the nearest tooth dead even with the magnet, then install the other dist in the same position (tooth dead even with magnet/rotor under same plug wire terminal). I'm assuming the rotor phaseing is near the same with either zigzag being used (been a long time since I seen one of those) but confirm by lining up the tooth with a magnet & see if the rotor is under or near under a cap terminal bulge (centered). See if it will fire up. You wont have advance so shut it down pretty much right away as it will get hot above idle but if it starts that's all we need to know for now.
live every 24 hour block of time like it's your last day on earth
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Re: '84 Chrysler 5th Avenue conversion from computer to ecu
[Re: dfixer]
#2433703
01/13/18 01:03 AM
01/13/18 01:03 AM
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Joined: Nov 2003
Posts: 36,041 Lincoln Nebraska
RapidRobert
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Actually I should not have suggested it, I forgot that it ain't like th old (2) zigzag dists that had 2 regular pickups slightly offset from 180 away from each other. To the best of my knowledge it is dist related, dragging will zap the plugs but the dist hooked up will not. Howabout we call Jegs & see what they are willing to do to help us resolve this. did we ohm the pickup? & with the scale on low AC volts on the zigzag if you spin the dist by hand will it give a reading?
live every 24 hour block of time like it's your last day on earth
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Re: '84 Chrysler 5th Avenue conversion from computer to ecu
[Re: RapidRobert]
#2434204
01/14/18 12:51 AM
01/14/18 12:51 AM
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Well I may have messed up my opportunity on any returns. I was going to pull the dist. to spin it to check to see if I would read any AC voltage. As many times as I have put dist caps on I have never had this happen, but when I pulled the cap I discovered the spring contact on the rotor was bent badly to one side. It was so bad, even though I tried to get it straight, it left an obvious crimp mark. But I did think maybe that was the problem, got it as straight as I could, put it back together but got the same results. I took it apart and it was bent again. I just knew that must be the problem so I put in the rotor from my most recent cap, rotor, plugs and wire change out. Still no change and when I pulled the cap that spring was bent a little too and then examining the inside of the cap it had obvious cuts in the copper ring around the carbon button at the center of the cap. I am sure, once Jegs got the return they would say it didn't work because I had damaged the cap and rotor. I am beginning to feel my boat rocking in the creek and the light is getting so dim I am not sure I can find the paddle.
When I got your post last night I looked back over my notes and we had checked the pickup coil and it measured 250 ohms. I apologize, in my frustration I didn't pull the dist to check the AC voltage output of the pickup. I will try to get that done tomorrow. I guess I could just have my helper crank the engine while I measure for AC at the zigzag connector, rather than pull the dist.
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Re: '84 Chrysler 5th Avenue conversion from computer to ecu
[Re: dfixer]
#2434340
01/14/18 12:07 PM
01/14/18 12:07 PM
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Joined: Nov 2003
Posts: 36,041 Lincoln Nebraska
RapidRobert
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is it possible that if we tossed in a new cap/rotor that we would be good? installing the cap straight down keeps the rotor tang from catching/bending but sometimes that is hard to do with the wires installed expecially if the lengths are slightly shorter than the normal amt & in that situation I pull the wires/install the cap/reinstall the wires. What would a dist cost at your parts house & what about one at a yard?.
live every 24 hour block of time like it's your last day on earth
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Re: '84 Chrysler 5th Avenue conversion from computer to ecu
[Re: scratchnfotraction]
#2436401
01/17/18 04:39 PM
01/17/18 04:39 PM
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Sounds interesting but I have a couple of questions. You said,". . . ask for a 67 - 72 points dist about 28$ at AZ." I don't know about your Auto Zone, but at mine they only know what to ask by what their computer tells them to ask, like what's the make, model, engine, etc. If I ask for a 67-72 points distributor I will get the deer in the headlights look and I have to admit, I am not any better. My other question is you said,". . .swapped my 85 truck over to points and waiting on my conversion kit to come in." What's in the conversion kit, where does it come from, or you still talking points conversion? What I have on order is a Cardon - this Jegs sure doesn't seem to be working. Thanks for your offer. That conversion sounds like it would at least give me another option. Sure do want to get my '84 back on the road.
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