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View Full Version : Sr20det coil pack/harness failure?


T40sx
01-01-2012, 04:51 PM
ok so upon much research, i've found little to no real answers to this conundrum. what is the reason for one or multiple coil pack failures? (and in this case, failure means an apparent short across said system.)

background. this is a slow and arduous task. i've spent countless dollars and even countless more hours, as well as a couple fluid ounces of blood on this motor. this was a full engine rebuild i started a few years back. it only just came to fruition. upon finishing the motor, i noted a bad knock in the head. turns out a cam spocket worked itself off on the intake side. removed and replaced the sprocket as well as the cam. not reshimed yet, i'm aware it needs to be. but for the sake of time and money, i'm letting it ride.

the problem is this. after reassembling the head, i noted the car was hesitant to start (slow and weak) i replaced the battery and that helped. but that's when the new problem occurred. when the car wouldn't start afterwards, only turn over. i popped the hood and noted an unusual smell followed by an abrupt spew of white smoke from cylinder #1 coil. needless to say, i pulled them all. the coil was completely melted between the coil power and the ecu signal wires.

my question is this. because of funds i reused the old ignitor, coils and ecu as well as the harness. up until this moment i haven't had much issues with them. however after building a new harness to within .02 ohms i reassembled the new harness with 2 new coils and the back 2 original that tested the lowest ohm reading. only to find that now #2 and #3 burnt up, as well as severe over heating on all but #4. i intend to replace the coils as well as try an OEM harness but since i'll be using a friends parts i'm wary to burn it up like mine. what are the implications involved in the ignition system? i know the ecu drivers, ignitor, and coils. but what could be causing this massive system failure all of a sudden?

i'm appreciative of any input or suggestions.

Tony

fliprayzin240sx
01-01-2012, 07:59 PM
Did you re-do the coilpack harness? If you did, how is the setup grounded? Most of the time, its a ground related issue. On my last SR20, I cut the ground for each coilpack and hooked a ring clip on each wire and grounded them each on under the coilpack retaining screws.

T40sx
01-01-2012, 11:20 PM
i considered that, but instead took into account the amount of "factory" resistance. thinking maybe nissan had an idea about that. but it was a crimped and soldered connection to the factory bolt at the back of the head. it was .06 ohm from the stock harness so that's what i went back with. it's obvious it's a short SOMEWHERE, but i'm pretty much just trying to figure A. if it's a short through a wiring aspect, i.e. the coil subharness, (which i thought i ruled that out by running the newly rebuilt harness.) or B. if it's a short through a component. i don't think it's ECU since i just put in a friends SR20 swap and it ran normal. so i suppose the question in turn is. yes i'll quadruple check the grounds, but could there be an issue with another component? i've gone through the schematics and it really looks like it just runs from the ECU to the ignitor to the coils. correct?

Tony

carnagexxxx
03-09-2013, 05:59 PM
Sorry to bring up an old thread but I was wondering if there was a solution to your problem, Tony.

I am now having a similar problem where the top of my Split Fire coil pack (new, never been used) is over heating and melting the plastic at the top.

I am really stumped.