MSD and Spark plug cables

[kasi]

Ok Guy's ,here we go again !!
After my cold start warm up problem , the engine is back in the car !!!
During my test drive my ignition control unit blew up !!!
So today i installed MSD 6420 with a MSD coil !!!
Engine starts ,runs on idle but as soon as i push the throotle i get backfire as if there is a war going on !!!

Do i need to change also my spark plug cables ??

I want anyway new spark plug cables because i still use the one with the steel around for the ground !!

Thank's

[Nitrometano]

What is the MSD 6420? That is the 6A or the 6AL. Check your ignition timing, spark plug firing order and fuel mixture. Begining with the firing order, the check the timing and for last the fuel mixture.

[Lukesportsman]

you don't have a 3.0 in something by chance and have the wires installed "normal" did you

[RoninLB]

some pelicanheads have said that the MSD will will toast old Beru wires and the rev limiting rotor, especially if the plug gaps are set to .040 as many MSD users do.

[stlrj]

MSD is not compatible with copper core ignition cables like your stock shielded Beru.

Beru's are only rated for a 0.028" plug gaps which would be a big waste of money after going to the trouble of adding a high energy MSD ignition that is capable of plug gaps of 0.060".

Even my 3.2 motronics are good enough to fire a 0.060" gap, but not with the stock Beru cables.

Cheers,

Joe
74 911 w/ 86 3.2

[kasi]

Ok guy's
Timing , firing order checked everything !!
I got some Clewette high performance cables here !!! Would they work ??

[mb911]

We as a company are currently working with msd to produce 911 specific ignition cables. I am awaiting some more samples but hopefully soon they will be done. I can tell you that my msd with beru wires works well except you do get signals on each wires causing the msd to misfire. So Thats why we are looking at the msd super conductor wires to resolve this. We are very close to a final product

[kasi]

I have an upgrade to 3.2 l with 98 mm JE Pistons !!
I found that when i disconnect the Vacumn line from the distributor that the backfire is gone ,on low rpm !! Backfire comes back around 5500 rpm !!
AAR is ok!!
Now the engine does not idle constant ,so i can't set the timing proper !
I got also a small Computer to adjust the mix ! if i messure on idle i get something around Lambda 0.8 ,during acceleration the mix gets leaner and around 5500rpm i got somethig like Lambda 1.15-1.20 !! then i also get backfire !!
Can someone please tell me what to do !?

[Paulporsche]

I just put an MSD on my car w/ a 3.2L conversion. My mechanic recommended 7.5 mm MSD Chevy wires. There seems to be a consensus that the OE wires are no good in this application. You don't need to worry about not using the braided steel wires--they were incorrectly thought to be a fix for airbox blowups.

What kind of erratic idle are you getting? Is it a low rpm stuttering ( which often means too lean) or a rhythmic fluctuation (too rich)? Is this when the engine is warm or cold?

Have you checked your control pressures/WUR?

Is your dizzy/advance working correctly?

Why not try those Clewettes and see if that helps?

[RoninLB]

Originally posted by mb911
We as a company are currently working with msd to produce 911 specific ignition cables.

great management imo

[mb911]

Originally posted by kasi
I have an upgrade to 3.2 l with 98 mm JE Pistons !!
I found that when i disconnect the Vacumn line from the distributor that the backfire is gone ,on low rpm !! Backfire comes back around 5500 rpm !!
AAR is ok!!
Now the engine does not idle constant ,so i can't set the timing proper !
I got also a small Computer to adjust the mix ! if i messure on idle i get something around Lambda 0.8 ,during acceleration the mix gets leaner and around 5500rpm i got somethig like Lambda 1.15-1.20 !! then i also get backfire !!
Can someone please tell me what to do !?

Same exact thing with mine thats why We are going to produce the MSD wire sets for porsche. Its the only answer when running this ignition

[kasi]

OK Guy's !!
I got now also MSD Sparkplug Cables on my 3.2 SS
Firing order 153426
Mixture Lambda 0.95
Engine idles now steady on 1100rpm but i can't set the timing My vacumn advance is disconnected and i see instead of Z1 the 35 mark ! And if i connect the vacumn the engine does not idle at all and i only get Backfire !!
What now ????

[Nitrometano]

hum...maybe the inner distributor springs and weights are rusted, dirt, etc and can not move freely.

[stlrj]

What vaccum advance? 3.2 Carrera engines never came with that.

[jdowty3]

Check and make sure you don't have the green and violet MSD wires reversed. Having these connections reversed will cause the symptom you described.

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
7 and 31D are the connections ID's for the 6 wire CDI plug.

[kasi]

Thank's !
I'll check this also !
Any ather ideas ????

[kasi]

Jim
Do you work a lot with MSD or did you make the same mistake i made ?? I did what you said and now the car run's perfectly smooth on 1000rpm!! Timing 5deg BTDC and my mix.is exactly Lambda 0.95!!!
I checked with my old harnes and on this one the shield wire is 31d !
Anyway ,finally the car runs great and thank's a lot to all of you guy's specially to Gunter and Jim !!!
And if someone is planing to go on holyday ,consider Aruba for a test drive !!!

[kasi]

Jesus,this thing is flying !!!

[jdowty3]

I made the same mistake when installing my 6A last summer.

[steviee7]

Just curious of which P car you installed this MSD on.
And was it worth it?

I'd like an MSD.