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FPH Gruppe
Join Date: Aug 2002
Location: Way up the left coast and inland a bit
Posts: 1,815
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Bosch 3 pin MSD question, long!
Alrighty then...
I have a 72 T that I saved from falling too far apart in the PO's garage. It had been sitting for a few years and I've gone through the fuel, electrical, ignition, brakes, replaced fluids, hoses and even dropped the motor and tranny chasing oil leaks and cleaning. A million thanks to this board for all the know how and encouragement on the journey! The situation I've run into now is this: In my trouble shooting to bring the ignition back to life, I diagnosed that the MSD and/or coil were dead. I replaced them with a Permatune CDI and new coil. Life got much more fun with a living breathing (smoking, dripping) 911... After several more months of tuning and even a couple of visits to Mr. Walker (yes! he deserves the praise he gets here) the car is running reasonably well and I got to wondering if the original Bosch box was my problem or a bad coil... so I stuck it back in the car. It ran better than it ever had, a low RPM stumble was gone and it pulled well to red line. I drove it for a couple of days. (I had the Permatune box + tools along just in case) Then, trouble, I fired it up to head home from work, it idled perfectly for about 25 seconds, then quit as if I'd pulled the coil wire and would not even spudder. I got out, checked fuses, pulled the cap... nothing, still would not start. I went ahead and changed back to the Permatune box, she fired right up and I drove home, low RPM stumble and miss was back too. Now I can't help but wonder if the Bosch 3 pin box is repairable? Anyone with sucess stories? I'd love to know what component usually goes out in them, and if I could repair it and enjoy a better running car again?
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Skip Newsom 72 911T Targa Signal Yellow Now sporting a big Port 3.0 built by THE John Walker |
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05-09-2003, 07:01 PM
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Registered
Join Date: May 2002
Location: Chews Landing, New Jersey
Posts: 272
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Skip,
I went through this problem. If the coil "goes", or is on the way out, failing when hot, it can take the box with it. Coils are cheaper than boxes. I have repaired a permatune (with Warren's help) I would imagine the MSD is similar. I originally located my problem by waiting for it fail and checking the 300v output with a 600v neon. If you search "permatune" and my username you will find a lot of info. Jeff
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'72 911T gone '85 TVR |
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05-09-2003, 11:24 PM
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FPH Gruppe
Join Date: Aug 2002
Location: Way up the left coast and inland a bit
Posts: 1,815
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Thanks Jeff!
The nice thing about the Bosch is... no potting!! I'm still wondering if anyone out there has a wiring diagram with component values for the 3 pin boxs?
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Skip Newsom 72 911T Targa Signal Yellow Now sporting a big Port 3.0 built by THE John Walker |
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05-12-2003, 06:46 AM
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Senior Member
Join Date: Apr 2001
Location: Finland
Posts: 1,214
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Well...here goes...there are different versions of this thingie..not sure if this is legal but moderator may remove it if he wishes:
 
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Projects: 911 -72T EFI "964-look" "Smoky" 914 -71 1.7 D-JET "Rusty" |
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05-12-2003, 06:58 AM
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