Problem with MSD up grade

JLW · 08-10-2005, 05:56 AM

I just installed an MSD ignition with a blaster coil. I also replaced distributer cap, rotor and plugs. I set the gap as described in Wayne's book. With this up grade, would the timing need to be reset?

My problem is I have rough idle and while driving when I reach 5000 rpm the car will stop accelerating and start to miss badly. When I let off the gas and slow down it will smooth out again.
I have changed fuel pump, fuel pump relay and filter in the last 100 miles. One thing I have not done is replace plug wires.

This is starting to get expensive. Please HELP.

jstobo · 08-10-2005, 06:31 AM

If you have stock spark plug wires with Beru connectors they could be your problem. With the MSD a non solid core wire is needed. Also check your timing. Sounds like you may be too advanced. Of course the timing check is the easiest and quickest. Always the place to start.

Jim

B D · 08-10-2005, 07:52 AM

You must get the correct wires, you may have already fried one and be running on 5 cyl. and therefore a rough idle. Timing should not need to be reset, but with all the ignition work it would be wise.

jdowty3 · jdowty3's Garage

check to make sure you do not have the Magnetic pickup wires reversed. I had similar symptoms when I accidentally connected the violet MSD wire to the green distributor wire and the green MSD wire to the shielding around the green distributor wire.

here's the wiring info I used for my 83 with a 6 pin CDI

Large red is 12v power and large black is chassis ground.
Brown wire to coil neg is 31-1 and connects to MSD thin black wire
White wire to coil pos. is A and connects to MSD orange wire
Red switched power wire is 15 and connects to MSD thin red
Green wire from distributor is 7 and connects to MSD magnetic pick-up green wire
Shield wire around distributor green wire is 31D and connects to MSD voilet wire
All that leaves is a black wire (with violet stripe?) that connects to the MSD Tach output connector and the MSD white wire.
If you have points, you use the white wire and leave the magnetic pick-up wires disconnected.

Superman · 08-10-2005, 08:25 AM

JW says the MSD units don't work well with the SC's. Folks who think MSD is the end-all of ignition systems are wrong. Folks who thing Permatune is best, are also wrong. I don't know why anybody would use anything but the Bosch factory unit.

stlrj · 11:23 AM

Quote:

JW says the MSD units don't work well with the SC's

But were they installed in engines with the stock Beru ignition cables?

On my previous 3.0, I had good results using a GM Delco transistorized module in place of the Bosch CD with an HEI coil on carbon core ignition wires with plugs gapped at .060".

My current 3.2, I'm still using carbon core wires with the stock DME ignition which is capable of firing my plugs at .060" better than the orignial Beru's could ever do at 0.28".

Joe

ckissick · 08-10-2005, 09:07 AM

My car runs so great with the Bosch unit, I've seen no reason to change anything. I think Supe may have something there.

jdowty3 · jdowty3's Garage

I found the MSD CDI with an MSD coil to work great on my 83 SC. Better low end torque, smoother mid range power up to the red line, and an added 1.5 MPG's consistenly. I am running Magnacore wires but have not regapped my plugs yet.

Early_S_Man · 08-10-2005, 09:42 AM

JLW,

Is the coil you used the epoxy-filled High Vibration coil?

JLW · 08-10-2005, 09:45 AM

I used the Hi Vibration Blaster coil that our host sells to go with the MSD.

RoninLB · 08-10-2005, 10:27 AM

I used magnacore and a non rev limiting rotor. The rev limiting rotor can also be bypassed with a soldered pin or jump wire.

Rex Walter · 08-10-2005, 10:51 AM

Quote:

I don't know why anybody would use anything but the Bosch factory unit.

Really? Our host sells the MSD units for about $225 to $300. The factory Bosch units are 74-77 = $1824.00 and the 79-83 = $1893.00. For me, the decision was easy. Modern electronics, and much cheaper prices.

Rex

RoninLB · 08-10-2005, 11:15 AM

http://forums.pelicanparts.com/porsche-911-technical-forum/213066-rotor-button-melting-why-2.html#post1832405

Jeff Higgins · 08-10-2005, 11:26 AM

To add to the info in RoninLb's link, there is a tall rotor and a short rotor used in VW Bug distributors. You want the tall one. If in doubt, bring your rev-limiting rotor with you and match the height. They fit the shaft perfectly and don't wobble.

randywebb · 08-10-2005, 12:08 PM

Modern electronics... actually, except for the multi-sp[ark feature, I don't think we know that the circuit design is improved. But, certainly, the components will be newer than a used Bosch unit.

vash · vash's Garage

my SC will rev to the heavens. MSD, hi vibe coil, and beru wires. PO installed it tho.

RoninLB · 08-10-2005, 01:11 PM

Quote:

Originally posted by RoninLB
I used magnacore and a non rev limiting rotor. The rev limiting rotor can also be bypassed with a soldered pin or jump wire.

I found the pn that was on a Pelican receipt. BOS-04038 @ $4.95 in 3/7/2002

I tried plugging the #'s into the pelican part search at the top of this page and it wouldn't come up.

Early_S_Man · 08-10-2005, 01:32 PM

The admonition not to use solid wires is strictly to minimize RFI/EMI interference with other systems in the car, and has nothing to do with any potential damage or running issues with the MSD! Many people have used stock Beru wires, or other solid-core wires with MSD ... and had no problems.

The biggest issue with MSD causing misses or other drivability problems is pinholes, cracked, and damaged ignition wires that can cause arcing and corona-effect ... visible at night or in a dark garage with the engine running! Every arc or glow you see is energy that isn't getting to the spark plug!