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Pulling my hair out, engine misses at 4K...

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Old 08-14-2007, 08:45 PM
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I'm guessing weak/cracked valve spring(s) and they are getting worse.
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Old 08-29-2007, 10:15 AM
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Have you found the problem yet?
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Old 08-29-2007, 07:06 PM
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No, but the situation has improved. Turns out one of the ignition modules I swapped in to replace the Crane box was faulty. Tried a V8-24 Module and it got better. Next up is the V8-20 off a HP 500. I may have got the rockers adjusted a smidge too tight. I suspect that may be where a few of my RPM have gone. Right now it runs clean up to 4800 and fails to build RPM past that. Boost is normal, compression and leakdown fine.
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Old 08-31-2007, 10:27 AM
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Do you have the non-adjustable rockers? If so what torque did you use?

Funny thing after I started reading your string my Checkmate started do a similar thing. Maybe its bad ora. Going to work on my problem today. I hope it might be a loose wire somewhere.
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Old 08-31-2007, 10:59 AM
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A cracked valve will do exactly what you have described. You will also not be able to get to full rpm.
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Old 09-10-2007, 08:26 PM
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Here is what I did. Jumped directly from + Bat. to + Coil and solved problem. I figure long small gauge (old) wire all the way to dash and back to coil is sucking Vs/amps. Plan to put key relay near coil to solve problem. Will post results.
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Old 09-10-2007, 08:40 PM
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I meant to update this. The HP 500 module solved my problem. Only minor issue left is a slight stumble when trimming at WOT. I am also pursuing the relay to activate clean 12V to coil. Might be a lot easier than running all new wire from harness to dash and back. Should have been built that way to start. If I go this route a blocking diode will be used across the relay coil.
http://www.bcae1.com/relays.htm
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Old 09-12-2007, 08:53 AM
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Baddog,

Tell me about the blocking diode. What is it for and were does it go? I was just going to use the relay near the coil.

Followup: I used the ling in your above e-mail "I see" said the blind man.

I have two relays Hella and PIAA from off road light systems I used. They both have built in diodes and the Hella has a 10 amp fuse. These are way over kill but I have them and they should last.

Last edited by TAZMAN; 09-12-2007 at 09:19 AM. Reason: Follow up
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Old 09-12-2007, 09:30 AM
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Talking Rocket Science

Oh BTW "I" figured this out after several weeks of having this problem and wrapping wires, separating wires, replacing wires, cleaning contacts (Baddog you know the drill) I finally asked my dad about the problem. Who is an aeronautical engineer (rocket scientist) he said immediately jump from +bat to +coil, if the stumble goes away take the jumper off and install an ignition relay between the key and the coil near the coil.

Never be to proud to ask good ol' dad for help .

Hey baddog here's to solving the problem

Last edited by TAZMAN; 09-12-2007 at 09:32 AM.
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Old 09-12-2007, 09:39 AM
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Have you hugged your Dad lately?
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