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Bucking under acceleration

Old 09-02-2018, 11:42 PM
  #16  
spencang
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Thom, I saw your post about 2 hours AFTER I bought them from Lindsey...
I installed them today and it's fixed! My car actually feels like I just did a tune up. Definitely more responsive and I can finally feel the recent mods. The evergreen turbo, upgraded intercooler, lightened flywheel and lighter con rods = WOW!
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Old 09-02-2018, 11:51 PM
  #17  
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I meant "Tom"...thanks for the sage advice. It's always great when it works, too
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Old 09-03-2018, 12:04 AM
  #18  
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That's great!! Congrats! Which wires did you get?
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Old 09-03-2018, 09:23 PM
  #19  
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I got these: https://www.lindseyracing.com/LR/Por...09-566-FB.html
In blue. They have the protective sheath and fit pretty snugly.
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Old 09-04-2018, 06:24 PM
  #20  
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Wow, those wires look/sound very similar to the Clewett wires -- I wonder if LR makes them or buys them? Either way, they look good. The Clewett's are $85 for reference, plus I think $15 for special colors like Blue...
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Old 12-29-2018, 09:15 PM
  #21  
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So, the same thing is happening again. At first, the new spark plug wires seems to fix the problem but now it's back. It only happens in 3rd - 5th gears when cruising at 3000 rpm then getting on it, it bucks as if a cutoff is happening at around 3800 rpm. I can floor it in first and second all the way to redline with no issues.
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Old 12-29-2018, 11:39 PM
  #22  
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Originally Posted by spencang View Post
So, the same thing is happening again. At first, the new spark plug wires seems to fix the problem but now it's back. It only happens in 3rd - 5th gears when cruising at 3000 rpm then getting on it, it bucks as if a cutoff is happening at around 3800 rpm. I can floor it in first and second all the way to redline with no issues.
Since you have new wires, how are the cap, rotor, coil, and plugs? Any other symptoms? Sputtering under peak load like that is a classic weak ignition symptom, especially if it otherwise drives just fine. Yours could be something else of course, but odds are odds...
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Old 12-30-2018, 01:26 AM
  #23  
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I use an MSD ignition and I do have newish plugs, new blaster 2 coil and a newish rotor. Newish means within the last 18 months. My msd ignition is not new though. Is there a way to test those things to isolate what may need to replace?
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Old 12-30-2018, 02:13 AM
  #24  
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I noticed my cap and rotor wear more quickly now that I have an MSD blaster coil. I replace it once a year.
What's the plug gap? Do you know your AFR at full throttle?
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Old 12-30-2018, 02:18 PM
  #25  
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Originally Posted by spencang View Post
I use an MSD ignition and I do have newish plugs, new blaster 2 coil and a newish rotor. Newish means within the last 18 months. My msd ignition is not new though. Is there a way to test those things to isolate what may need to replace?
Can you easily bypass the MSD and run the car in regular inductive ignition mode? I have found that MSD boxes tend to be hard on secondary ignition components, and are really only necessary in older applications like Hemi-head 911s and Alfas.

Test it and get back to us. If the MSD is at fault, it might be worth sticking with regular ignition. Just the MSD Blaster coil alone should probably suffice with your modifications, though you could always go wasted spark as well.
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Old 12-30-2018, 03:40 PM
  #26  
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I will be checking the whole system today and let you guys know what I find.
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Old 12-30-2018, 04:59 PM
  #27  
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No spark! Failed the first test... I have the older MSD 6A. I did this test about 18 months ago and it sparked.

So what are your recommendations for replacement/reasonable upgrade?
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Old 12-31-2018, 02:48 AM
  #28  
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Originally Posted by spencang View Post
No spark! Failed the first test... I have the older MSD 6A. I did this test about 18 months ago and it sparked.

So what are your recommendations for replacement/reasonable upgrade?
I see what you are doing there, but that would be more indicative of a secondary ignition problem (ie a bad coil) rather than something on the primary side. If the MSD box were at fault, it would likely cause a no start/stalling issue.

This would be simple to verify: do the same test with the MSD box bypassed (wire the primary ignition circuit as it was from the factory).

EDIT: the above test might not pass with the coil in 12V inductive mode. A better test would be to wire the ignition as stock and take it for a test drive and see if the symptom goes away. Make sure you set the spark plug gaps back to stock if you had opened them up for use with the MSD 6AL.

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Old 12-31-2018, 02:56 PM
  #29  
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That was the test that MSD has on YouTube
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Old 12-31-2018, 02:59 PM
  #30  
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I did not install it, my old mechanic did it back in 2007, so what must I do to bypass the MSD and put back to stock?
Any other things that I need to consider?
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