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View Full Version : SR-No Spark! Need help from wiring Gurus!!


Gription
02-13-2011, 10:06 PM
So I made a thread about this issue before but I guess no one quite understood what I was talking about, so I've broken it down to make is easier to see what I already know and don't know, what I've tested, and what is working and what isn't. I searched around and the closest I came to an answer was here (http://zilvia.net/f/engine-tech/251932-please-help-me-make-s14-sr-start-please.html), but it came to a dead end.
Anyway, I just finished making my own ignition and chassis harness and now I am getting no spark whatsoever. Below is a list of my setup, an exact diagram of the ignition harness I'm running, and a list of things I have tested.

-First and foremost the car does not matter whatsoever because there is not a single oem wire remaining. Everything has been thrown out and replaced with my own ignition and body harness.
-Motor is s14sr20 with WC ecu.
-I'm canceling out the engine harness as an issue because I used it on my last setup just as it is now and it has always worked fine.

Here is everything I've tested:
Spark Plugs- OK
Ignitor Chip- OK
Coil Packs- OK
Fuel pump & injectors- OK
Cam angle sensor:
-180* singnal- OK
-1* signal- No voltage reading
-All cam angle sensor wires have tested good continuity through the harness to the ecu.

I've gone through ecu pinouts and wiring diagrams and I can see that there are 2 main +12v wires coming from the eccs relay that give power to the ecu, which I will elaborate on a little further down. On my setup, one of these wires is carrying voltage and the other is not.

Here is a diagram of my harness which controls fuel, ignition, and power to the car and ecu.
http://i14.photobucket.com/albums/a311/strikebackbmx/Onevia/s14srcustomharness.jpg

Next is a pinout diagram of my ecu to give you some more input on what I've got, which can be viewed here- http://www.kouki.co.uk/reference/nissan-200sx-s14-sr20det-ecu-pinouts

The part of interest to me is at the eccs relay which is supposed to carry power through 2 main wires to the ecu. Here is a closeup of that diagram.
http://i14.photobucket.com/albums/a311/strikebackbmx/Onevia/eccsrelay.jpg

-The coiled wire coming from the relay (pin 85) is carrying +12v to pin #16 on the ecu.
-The switched wire coming from the relay (pin 87) has no voltage reading to pins #49, #59, or the B/W wire leading to the engine harness.

To test this out as being a problem, I bypassed the relay and got +12v to ecu pins #49, #59, and the B/W wire leading to the engine harness and I still had:
-No spark
-No voltage reading on the 1* cam angle sensor lead.

So I'm in a bind and I have no idea what is causing my no spark issue. Today I got curious so I tested all 4 wires on the CAS using these instructions from the fsm:
http://i44.photobucket.com/albums/f20/iam2pro4u/cascheck.jpg

-I still got a .01-5v reading on the 180* signal lead
-Still no voltage on the 1* signal lead (labeled #2 in the instruction diagram)
-12v on pin #3, which carries power to the cas
-.01-1v reading on the #4 pin, which should be ground(?)

Should the ground lead on the CAS be fluctuating when the rotor turns? I found this a little odd and thought maybe I somehow crossed up the ground and 1* signal wires?? I dunno.

I've traced damn near every wire in the car and I have no new ideas of what could be causing this. Any wiring gurus out there who may have an idea or an answer, I really need your help! Thanks :D

KaminaSan
02-14-2011, 12:02 AM
I hate to sound like an ass.

I don't know shit about wiring... AT ALL.

K.I.S.S

Keep it Simple, Stupid.

Through your entire post, I saw you check all these complicated things...

Did you check to make sure your ECU is not FRIED? Have you replaced the ECU?

Gription
02-15-2011, 09:57 PM
I don't think the ecu is fried because the injectors are firing and fuel pump is priming.

Davidna2fi
02-16-2011, 10:36 AM
Do this, disconenct battery for like 20 minutes, then reconnect and just try to turn it over, if it kicks once like it fired and then doesn't fire anymore, then it's your CAS stabbing that is messing it up. If injectors are firing the ECU is not fried, possibly bad ignitor, but rarely do those go bad. Wiring is pretty simple with the coilpack system. Do this and get back to thread. Or do you always discconnect battery for a couple minutes each time you mess with wiring, if so, it's wiring, if not, then try and restab the CAS and unplug the battery. The reason being is that nissan's failsafe system throws the ECU into limp mode when it senses knock at a certain time, and the CAS being stabbed incorrectly will definately cause a knock and it'll be picked up.

Gription
02-16-2011, 04:48 PM
I know it's in the wiring I just don't know where.

Davidna2fi
02-16-2011, 06:56 PM
So you never removed the CAS or anything from the engine before you did a wire tuck? If so, then ya it's wiring.

Ground at the back of the head for the coil pack harness? You need a really thick ground for the coilpack harness, almost same gauge as an ignition switch, if you have no ground for coil pack harness ITSELF, meaning nothing else grounding, then thats your issue, your trying to squeeze too many amps through the wiring and it's getting high resistance when it trys to energize.

Gription
02-16-2011, 07:11 PM
It's not anything on the coil pack harness and it's not anything on the engine harness, nor does it have anything to do with the wire tuck. Like I said I used this same engine harness on my last setup and it ran fine and I haven't changed it since. This has got to be something between the ignition harness and the ecu.