Datsun Roadster Forum-311s.org

I am still having issues with engine miss. Checked all the usual suspects, cap, cables, fuel pressure etc. Then I came across this video of a YouTuber with a crappy running bike (Missfires). Pretty interesting video as the test really shows quite a substantial difference between resister and nonresister. I’ve been running BPR6es. I’ll get some BP6es and report back.

What does MSD say to use? From what I've read it appears to be more important to match systems to plugs, i.e. if the ignition system is designed for resister plugs then going non-resistor is bad, and vise versa.

Tom
If you use a new distributor cap, does it miss? If not, could be the ionization in the cap leading to deposits= intermittent miss. Suggestion is to drill the cap.I did and no more deposits, no more miss. A new cap was always perfect, so the culprit was deposits. A known issue with MSD. Of course any wire breakdown can give a regular or irregular miss too.
I think I am using the BPR6ES also. You can widen the gap as suggested by many.
Good luck,
Linda

The saga continues. The cap has been drilled and it first seemed to miss more as the car was driven awhile. At one point I replaced the Blaster 2 coil since I have a spare. Thought all was good as It smoothed out. Next day it was missing again. All my sparkplugs ohmed out to factory specs. All MSD cables ohmed out good. All contacts are good. At times during a drive it doesn’t miss at all then most times it does. Driving me nutts! Only thing I hadn’t replaced were the plugs when I came across this video. The spark according to this video is almost 3 times higher with the non resistor than resister plugs. That’s significant!

Tom
Cap was drilled level with the rotor? Is the distributor good, no rotor wobble?
Also I found that the MSD box must have a very good connection. Is there any excessive vibration jostling connections?
Maybe a pic of your set up would help.
Sent a PM with more info
Also: viewtopic.php?f=3&t=18507
Linda

SU or Sidedrafts? Define "miss". Does it ever backfire as though the fuel did not get burned, was exhausted and then ignited in the exhaust pipe? Loose wires or Connections? Fuel delivery issues (plugged jets, plugged accelerator jets if sidedrafts).

I don’t recall any popping in the exhaust. Tried several needle sets and still the same. Does seem to do it more once the engine warms up though.

I’ve been trying to chase down a engine miss for awhile and think I found the culprit. Since my jetting was known to be pretty good as I have been driving it for sometime, I went thru the entire electrical system again replacing Caps, Rotor and checking plug connections. No change so I started down the path of checking out the ign pickup coil and IGN module on the E -Dizzy. Pickup coil ohmed out at 400ohm and then went to check the green/red wires that attach the pickup coil to ign module and found that there was a lot of corrosion at the terminals. Cleaned it all up and so far no miss. Thanks to Gary Boone and Dave Brisco troubleshooting page in Wiki the car seems ok now. Also replaced plugs with NGKBP6es. No, the resistor plug had nothing to do with issue. Running MSD seems to eat up all my connections or oxidize them.

Tom,
Good catch on the miss from the EI trigger. Have you also tried the BP6ES-11 plug?
Another link to add to the above on plugs:
viewtopic.php?f=2&t=7040
Garry Boone’s troubleshooting page in Tech Wiki is excellent for those interested:
http://www.311s.org/pmwiki-311/pmwiki.p ... yGaryBoone
I think there is a check for the module, as well as the pickup coil. I have replaced the pickup coil once . And I have a spare module in the glove box.

Linda