Intermittent MSD 6AL-2? *UDPATE*
#1198707
03/17/12 11:47 PM
03/17/12 11:47 PM
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Joined: May 2005
Posts: 598 NC, USA
davenc
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mopar
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OP
mopar
Joined: May 2005
Posts: 598
NC, USA
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Has anyone else experienced intermittent failures with a MSD 6AL-2? I had the motor apart over the winter for some head work. Since putting the motor back together I now have an intermittent ignition problem. After first firing the motor I spent a little time adjusting timing and carb. Once I thought it was in the right ballpark, I shut the engine off in order to disconnect the test equipment. To my surprise, the motor would not start back up. I tinkered with the carb and timing to try to put it back to the earlier state when the engine first started but that didn't help. There was no problem with fuel. After trying for a while I finally gave up, thinking that perhaps the battery was low after sitting all winter and the amount of cranking I had done. The following weekend, I tried again and the car started right up. The timing and carb were put back their best settings at the time, and I went for a drive. The drive lasted about 15 minutes, and as I was approaching my subdivision the engine suddenly died. I tried to restart it but I could tell from the sound that there was no fire in the holes. After getting the car back to my house (interesting experience since I was 1/2 mile away when it died) I tried the MSD diagnostic of putting the coil wire close to ground and shorting across the green and purple trigger wires. There was no spark. At the time I thought this pointed to the box so I called MSD during the week. The MSD Tech said that if you don't short these wires in a periodic fashion like an actual ignition signal that the box will ignore the signal and not fire the coil. The Tech thought it was more likely a problem with my distributor (MoPerformance). Friday night I pulled the distributor and gave it a good look over. The reluctor gap was a bit wider than 0.008 so I snugged it to 0.006. The pickup impedance was 328ohms. I have seen some posts which indicate this should be more like 500-600 but I have 2 other pickups that measured in the upper 200s, so for now I am considering that OK. I measured the AC voltage while spinning the distributor and could get anywhere from 0.7 to 1.1 depending on how fast it was moving. Today I started the car and again set timing and carb after letting it warm up. After tinkering for 20-30 minutes the engine again just quit. I had tested my test technique with the trigger signal before firing the car and proved to myself that I could tap a shorting wire across the purple/green mag trigger wires and get a good series of sparks between coil wire and ground. Once the motor died, I tried this same thing and got nothing. This test bypasses the distributor so I feel that is ruled out as the problem. To rule out the coil, I connected the battery positive via jumper directly to the + terminal of the coil (MSD Blaster SS), and jumped the - terminal of the coil to the battery negative. When I broke the connection to the negative, I would get a weak spark. This spark was much weaker then what the MSD generates, so I tried the same test with a second coil and observed the same weak spark results. Based on that I suspect the weak spark is due to the speed at which I can pull the jumper wire from the battery negative and is not indicative of a coil problem. I hadn't tried the coil test prior to initial fire but I will try that next time. So I am again thinking the problem is the 6AL-2 box. Something makes it get into a state which it will not fire the coil. I don't know if it is temperature (the box is not hot to touch but the engine was up to operating temp and the ignition box is on the inner fender) or just operation time. I will be calling MSD again on Monday, but in the mean time, does anyone have suggestions on other tests I can try? Last time I spoke to MSD the Tech said the boxes don't get intermittent; they either work or not. I am doubtful though. I have gone thru the wiring several times and everything is tight. The MSD red and black go direct to the battery and the MSD red run wire has 12V on it when there is no spark. Thanks for the input. Dave
Last edited by davenc; 04/15/12 12:08 PM.
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Re: Intermittent MSD 6AL-2?
[Re: davenc]
#1198708
03/18/12 12:00 AM
03/18/12 12:00 AM
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Joined: Jan 2003
Posts: 5,875 communist bloc of new jersey
jamesc
master
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master
Joined: Jan 2003
Posts: 5,875
communist bloc of new jersey
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Quote:
Last time I spoke to MSD the Tech said the boxes don't get intermittent; they either work or not.
i can't believe anyone that has ever worked with electronics would make a statement like that. without going through a lengthy explanation of diagnostics which may or may not discover the problem usually the best way to start checking something like this is with a known good component. there is always the possibility that there is a wiring or similar problem that could damage the new component but it's normally worth the risk. if you put a known good box in it and the problem is solved you have your answer if not then further checking is required. having an ignition tester at hand is also helpful but intermittent problems are the worst.
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Re: Intermittent MSD 6AL-2?
[Re: davenc]
#1198710
03/18/12 10:37 AM
03/18/12 10:37 AM
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Joined: Apr 2005
Posts: 4,923 new berlin wisconsin
Mr T2U
master
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master
Joined: Apr 2005
Posts: 4,923
new berlin wisconsin
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i had some intermittent hot starting problems with my msd6al. it turned out to be a bad pickup in the distributor.
perception is 90% of reality
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Re: Intermittent MSD 6AL-2?
[Re: Mr T2U]
#1198711
03/18/12 11:11 AM
03/18/12 11:11 AM
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Joined: Jan 2003
Posts: 1,379 Houston,Tx.
Lee446
pro stock
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pro stock
Joined: Jan 2003
Posts: 1,379
Houston,Tx.
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I just went thru this exact same thing. I swapped coils, distributors. I checked and rechecked all grounds and power leads. Car would run anywhere from 10-20 minutes and die, after approx a ten minute cool down, it would repeat the cycle. I happen to have a spare 6al, put it in, no more problems! I need to send it back to MSD, not looking forward to arguing with them to get a return authorization. I am an electronics tech and anyone who would say electronics cannot develop intermittant problems have never worked with electronic devices! Good luck!
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Re: Intermittent MSD 6AL-2?
[Re: Mr T2U]
#1198712
03/18/12 11:11 AM
03/18/12 11:11 AM
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Joined: May 2005
Posts: 598 NC, USA
davenc
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"i had some intermittent hot starting problems with my msd6al. it turned out to be a bad pickup in the distributor. "
I had considered this, and I believe this is what the MSD Tech was thinking. However, once the ignition was not working, I tried to trigger the MSD directly from the trigger wires (distributor is no longer in the system) and I was not getting any spark. When everything is cold, I can reliably get spark by shorting a wire across the green/purple wires in a periodic fashion (tap-tap-tap). In my first attempt at this test I was only sporadically shorting the wire, and apparently the MSD may ignore such a signal since it does not look like an ignition pulse. If anyone tries this remember to tap in a rapid, constant pulse.
If it comes down to me having to buy another box, I will likely replace the pickup first, just in case.
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Re: Intermittent MSD 6AL-2?
[Re: davenc]
#1198714
03/18/12 12:38 PM
03/18/12 12:38 PM
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Joined: Jan 2003
Posts: 1,235 TN
65racer
2009 IHRA World Champion
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2009 IHRA World Champion
Joined: Jan 2003
Posts: 1,235
TN
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Had the same problem several seasons ago, changed the box and all is well, just had to replace it again this past season, the msd boxes are not as good as they used to be, imho, they don't stand up like they used to. Don't send it back to msd, send it to Pat Collins at, www.techwestracing.comcheck out their web site, and give Pat a call, you won't be sorry. Dave
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Re: Intermittent MSD 6AL-2?
[Re: 65racer]
#1198717
03/18/12 02:33 PM
03/18/12 02:33 PM
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Joined: Dec 2004
Posts: 10,558 Rittman Ohio
fourgearsavoy
I Live Here
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I Live Here
Joined: Dec 2004
Posts: 10,558
Rittman Ohio
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Quote:
Had the same problem several seasons ago, changed the box and all is well, just had to replace it again this past season, the msd boxes are not as good as they used to be, imho, they don't stand up like they used to.
Don't send it back to msd, send it to Pat Collins at,
www.techwestracing.com
check out their web site, and give Pat a call, you won't be sorry.
Dave
Thanks Dave Some very good information on that site If my current box fails I will be sure and get out there. Gus
64 Plymouth Savoy 493 Indy EZ's by Nick at Compu-Flow 5-Speed Richmond faceplate Liberty box Dana 60
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Re: Intermittent MSD 6AL-2?
[Re: fourgearsavoy]
#1198718
03/18/12 03:27 PM
03/18/12 03:27 PM
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Joined: Jan 2003
Posts: 1,235 TN
65racer
2009 IHRA World Champion
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2009 IHRA World Champion
Joined: Jan 2003
Posts: 1,235
TN
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Quote:
Quote:
Had the same problem several seasons ago, changed the box and all is well, just had to replace it again this past season, the msd boxes are not as good as they used to be, imho, they don't stand up like they used to.
Don't send it back to msd, send it to Pat Collins at,
www.techwestracing.com
check out their web site, and give Pat a call, you won't be sorry.
Dave
Thanks Dave Some very good information on that site If my current box fails I will be sure and get out there. Gus
Gus,
Don't wait for it to fail, if you have a couple of weeks between races, send it to them and let Pat tune it up, you won't be sorry, and don't be surprised when he tells you to go to autozone and get a coil for the msd, I changed mine out to the one he suggested, and you would not believe the difference it made in the car.
Dave
PS part number from autozone is C-839
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Re: Intermittent MSD 6AL-2?
[Re: 65racer]
#1198719
03/18/12 07:21 PM
03/18/12 07:21 PM
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Joined: Dec 2004
Posts: 10,558 Rittman Ohio
fourgearsavoy
I Live Here
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I Live Here
Joined: Dec 2004
Posts: 10,558
Rittman Ohio
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I plan on calling them anyway about an old 404BC box that used to run really well on my car then one day during warm up it just shut off. Thanks for the tip on sending out my old one I think I will send them my spare 6AL along with my old 404 gold box. Gus
64 Plymouth Savoy 493 Indy EZ's by Nick at Compu-Flow 5-Speed Richmond faceplate Liberty box Dana 60
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Re: Intermittent MSD 6AL-2?
[Re: davenc]
#1198720
04/15/12 12:07 PM
04/15/12 12:07 PM
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Joined: May 2005
Posts: 598 NC, USA
davenc
OP
mopar
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OP
mopar
Joined: May 2005
Posts: 598
NC, USA
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Just wanted to provide an update on my saga.... I did speak with Pat Collins, and he seems like a knowledgeable guy. Very friendly and he spent some time on the phone with me, discussing my problem on his time. Definitely someone I would recommend if you have a need for ignition work... Anyway, after talking with Pat I still had some uncertainty on whether my problem was the 6AL-2 or something else. I tried to re-create the problem again, and to my chagrin, the car ran fine for about 45 minutes, at which point I decided not to keep idling the car in the driveway. However I was still scared to take the car far from home in case it left me on the side of the road again. As an experiment, I decided to buy one of the MSD Streetfire units since it was pretty inexpensive, and plug compatible with the 6AL-2. I swapped the Streetfire in a few weeks ago, and have been driving the car locally for a few weekends. Never had a problem and my suspicion on the 6AL-2 was escalating. That is, until last evening. I did some work on the car during the day on Saturday, and decided to take the car out just prior to dinnertime. As I am driving along, I feel the ignition stop for just a second and then come back. All of the sudden I am hoping that I can the car home quickly. Unfortunately I get caught at a long light, and once it turns green I don't get very far before the ignition quits completely. Luckily I was coming up on the local hospital and was able to roll the car into a mostly empty portion of the parking lot. I thought about checking with the folks in the ER to see if anyone could revive the patient, but decided they probably would not see the humor in that. Anyway after having the wife come retrieve me and eating some dinner I returned to the car with tools and meters. Again I confirmed the 12V source to the box was getting voltage, and tried triggering a spark by tapping on the green/purple trigger lines connected to the distributor. No spark. After staring at the car for a bit, I remembered that there was a cable extending the trigger wires from the box. Going to the trigger inputs at the first connector, and re-trying the experiment....ah ha! Spark!!! My mood started improving immediately, as I traced back the trigger wires to the distributor. I could still get spark by jumping the connector at the end of the extension trigger wire which MSD provides. The only section left is where I mated the MSD trigger wires to the stock Chrysler wiring to the distributor. So, it appears I only have myself to blame. I am going to look at it closer today, but it looks like two dumb mistakes on my part: I used crimp style butt splices (instead of soldering), and I reused the original Chrysler 2 wire molded connector. My tests last night indicated there is something intermittent in the molded connector... Anyway just wanted to update this post since I had cast some doubt on the MSD box.
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Re: Intermittent MSD 6AL-2?
[Re: davenc]
#1198721
04/15/12 12:28 PM
04/15/12 12:28 PM
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Joined: Jan 2003
Posts: 5,875 communist bloc of new jersey
jamesc
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master
Joined: Jan 2003
Posts: 5,875
communist bloc of new jersey
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Quote:
I used crimp style butt splices (instead of soldering)
soldering things is not necessarily the answer, i learned that the hard way. i made the mistake of soldering though i had been warned against it and it cost me a shot at defending a national title. i went from a magneto to a MSD, soldered and heat shrunk everything (teflon MIL spec wire). couple races into the season i start having intermittent loss of ignition during a run which aside from costing me the round would damage a $200 shift fork (drag bike trans). checked things time and again, gave up and decided to go back to the mag. while removing the MSD the last wire i went to remove on one of the coils came out of the heat shrink fractured at the teminal...which is what i was warned against by someone that works on very high end uninterruptible flywheel power supplies (like the ones used for cray computers). afaik aircraft wiring is crimped not soldered. solder can/will wick up the wire and with vibration can cause a fracture. the problem with crimping is people don't use the right quality connectors and crimping tools.
i was warned not to solder and thought i knew better...i was wrong
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Re: Intermittent MSD 6AL-2?
[Re: jamesc]
#1198722
04/15/12 02:18 PM
04/15/12 02:18 PM
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Joined: Apr 2005
Posts: 4,923 new berlin wisconsin
Mr T2U
master
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master
Joined: Apr 2005
Posts: 4,923
new berlin wisconsin
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the factory recommended repair in AIR BAG wiring under the hood is DO NOT SODDER the connections. use heat sealing crimp connectors.
on any wire connection i make i use those connectors. they work great and are easy to work with.
perception is 90% of reality
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