X64v Posted May 23, 2007 Share Posted May 23, 2007 Alright, getting ready to go turbo, so I switched from running fuel only (running off coil negative, using the '73 dizzy with a pertronix ignitor) to controlling spark with an 82 zx n/a vr dizzy. Now I've got a real strange spark problem. Spark to cylinders 2, 3, 4, and 6 is totally steady and fine. But spark to 1 and 5 is doing some pretty crazy things. Cylinder 1 doesn't get spark when the engine is accelerating. When the rpm's are steady (idle, or being held at any rpm), it's alright, but when I give it some gas, the timing light totally goes out, no flashes at all. Spark to cylinder 5 is just dead inconsistant. It'll be fine for a few seconds, then nothing for a few seconds, then a spark here and there, etc. I have run spark control through megasquirt before without a problem using the '73 dizzy with the ignitor, I just didn't like to use it 'cause I would get tach spikes. I'm not getting any spikes or abnormal tach readings with the vr dizzy, so as far as I can tell, megasquirt is doing it's job without a problem. Regardless, megasquirt doesn't even know which cylinder is which, so it couldn't be picking out 1 and 5 for any reason. The rotor and cap are new, but it does the exact same thing with the old rotor and cap. Spark plugs and spark plug wires are fine, and are the same ones I was using the same day with the other distributor. I took some video (crappy quality, it's just my digital camera) of the problems. The frame rate is not fast enough to catch every flash from the timing light, but you can see when it's flashing and when it's not. Timing light reading cylinder 1: Timing light reading cylinder 5: From my understanding of this, I don't see how it could not be a mechanical problem with the distributor somehow, though I don't know what that would be. Any ideas? Quote Link to comment Share on other sites More sharing options...
Matt Cramer Posted May 23, 2007 Share Posted May 23, 2007 Well, just because a distributor cap is new doesn't mean it's good. I know in the slant six world, the NAPA-Echlin caps (a brand that ought to know better) are often ground off-center. Check to be sure that's not the case with yours. Quote Link to comment Share on other sites More sharing options...
X64v Posted May 23, 2007 Author Share Posted May 23, 2007 Alright, I ran a few more tests. I couldn't just flip the cap to see if it was off center, because it only fits on one way, but I did do something else. What I did was remove the dizzy base and bolt it back up the other way (rotated 180 degrees). I then rotated all the plug wires on the cap 180 degrees, so that they'd be in the correct position relative to the rotor, but in different spots on the cap. Started the engine, and guess what. 1 and 5 were still the problem, even though they were in different spots on the cap and relative to the dizzy. I swapped in different plug wires and moved plug wires around, and no matter what wires were where, the problems were always cylinders 1 and 5. I need the car for tomorrow, so I'm going to swap the other dizzy back in and go back to fuel only for a day. If that fixes it, then that will reafirm that the plugs/plug wires aren't the problem. Edit: Swapped dizzies, went back to fuel only, still had the same problem. Moved the spark plugs around....problem followed the spark plugs. Put in new ones and that was it, problem's gone. Freakin rediculous... Quote Link to comment Share on other sites More sharing options...
280zfreak Posted February 1, 2011 Share Posted February 1, 2011 Whaaaat? I would have thought that would have been the first thing you would have done... lol Quote Link to comment Share on other sites More sharing options...
Isaiah Posted March 16, 2011 Share Posted March 16, 2011 Whaaaat, 1350 days later? I would have thought that looking at the date is the first thing you would have done... Quote Link to comment Share on other sites More sharing options...
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