ka24de intermittent cas problem

[ferd1]

s13 ka-t in a 74 datsun 620, stock dizzy, external coil..

my cas seems to have a mind of its own deciding for itself when and when not to work. it can work flawlessly one day without a hiccup, and another day go out sporadically. it's never an issue first starting, but once it's running(on its fussy days) it will randomly go out and come back on. for example, from first starting up, everything will run well from say the first 10-30 minutes, but at some point while driving, the cas will go out. then i'd have to pull over and wait around while messing with the cas connector plug to get it to work again. once i get it going again, it can either work fine for the rest of the day, or be fussy and go out again, and i'd have to do the pull over and wait around while messing with the cas plug to get it going again. on the days it wants to work well, i have no problems at all.

the intermittent problem has happened under varying conditions, so it's hard to pinpoint or guess when it will go out. it has gone out while steadily cruising under vacuum, while under boost, while running in the cooler ect range(150-170°f) and warmer(170-200°f), while in varying ambient temps(60-80°f) and under varying rpm ranges. like i said before, it's very sporadic.

in my attempts to address the issue, this is what i've done:
thoroughly cleaned the harness connector, even went as far as depinning it and slightly pinching the connector terminals to assure a solid connector connection to the cas,
gone through three different distributors(original was a used one from ebay, second was a remanned dizzy from oreillys, third(current dizzy) was another remanned dizzy from oreillys that was warranteed from the second one

what i think might be happening:
1)cas is getting heat soaked..
although my ect temps seem to be in check, i'm not running an oil cooler, nor do i currently have an oil temp gauge. could it be possible that the oil is getting hot and the heat from the oil is getting transferred through the dizzy gear shaft heatsoaking the sensor? i figured this because when the cas goes out while driving, and i do the whole pull over and mess with the connector thing, maybe within that time to do all that, the sensor has enough time to cool down and work again. i've also noticed that moments before the cas wants to work again, my fuel pump relay and rpm reading off my nismotronic dash starts to spaz out while cranking. once this starts happening, i know the cas is about ready to work again, and sure enough, after this spaz out, the cas will start working again. maybe this spaz out is a sign of the circuitry within the sensor cooling down and working again?

or

2) i have terrible luck and i keep getting dizzys with faulty sensors. do remanned dizzys get new sensors? or do they just do a quick dizzy test and clean em up? if they dont get new sensors, maybe im getting dizzys with pre-existing intermittent cas problems? i've taken apart the dizzys and the sensor within the dizzy seems replaceable, but i can't find the sensor itself for sale anywhere, so my only option is to replace the whole damn thing.


anybody have any advice on this?

[frapjap]

Welcome to NICO! That sounds like a cool truck. Have you got any photos?

Bummer to hear about your troubles. I'll have someone help you out shortly.

[PapaSmurf2k3]

When you install the new dizzy, does the problem go away for a day or 2? Or is it immediately back again?

I've never had a problem with my crank angle sensors... the only thing I could think of is if you have a wiring issue somewhere other than the connector. Did you replace the wiring harness with a new set when you did the swap? And by new, I mean something from either the dealer, or www.wiringspecialties.com.