kbui

hello all,

so, yet another sr20det no spark. 1st off, car is 93 s13 with sr20 blacktop. motor has been rebuilt, etc, etc, etc. for the last 2 weeks, i have been trying to figure out why the motor won't turn over. it cranks and cranks, but doesn't turn.
onto the diagnostics...using the multimeter;

1. I discovered that the ecu had a bad ground and power; fixed it and replaced ecu since the last one was burnt. still has good ground and power.

2. fuel pump was bad and replaced it, now priming at ~36psi with key to 'on'

3. did some testing on the cas, 1st one was bad. the 2nd one is good and checked my timing with the 2 marks and 2nd notch on crank pulley. did this multiple times.

4. checked the ignition chip...1st one was bad and 2nd one turned out to be good. checked the wiring and continuity from the chip to the coil pack and that was good.

5. after all of this diagnostics, i still did not get any spark. so i decided to check continuity on the grounds from the ecu connector. there was no ground on the maf sensor (pin 17) and no ground on pin #21 and 29, (consult port ground and oxygen sensor ground). checked continuity of the coil pack ground, that was good. and there is also power to the packs. o... and checked the coils themselves vs. the fsm, and they are good.

6. after fixing the grounds mentioned above, still no spark. so now i feel like selling everything...lol.

the car does have power to the ecm, ignitor and its wiring is good, cas has voltage on the signal wires and a good ground. coils are good and are getting power. coil pack ground is good. spark plugs are good and aren't fouled. fuses and relays are good.

i can't figure this crap out. Any suggestions?

I did multiple google searches and searches on here, which is what i came up with in the diagnostic steps. i thought it was for sure the cas but using the new one that i bought didn't help the situation. now, i am asking you guys. i am really stumped and cannot figure it out.

lmk
thanks in advance and sorry since this is a repeating topic...i just really want my car to start...lol

kbui

Vernal

so power at every coil connector? if you were to lay a spark plug on the valve cover and turn it over there would be no spark in each plug?

kbui

^ yes, that's exactly what i did and no spark. also forgot to mention that i checked the wiring multiple times.

thx

kbui

Help please?...bump

redline racer510

I"m no SR20 expert, but your saying your getting power to the coils but when you stick a spark plug in them and ground it to the valve cover your not getting a spark. To me it sounds like you have bad coil packs. Your getting power all the way to you CP but no spark, you do the math.

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Uncivil240

Same what he said , I would just get a coil pack from a working car and test it , if its getting spark then you know what your problem is. I had the same thing happen on my RX8 all the coil packs read good on the ohms but the car still didn't spark or start , bought a set online off the forum, sh!t cranked right up.

kbui

hmm....so i replaced the coil packs and still nothing! i rechecked my diagnositcs again, and found out that i have constant ground, constant power (cranking), but no pulsing ground. checked my wiring from ecu to ignitor and continuity from ignitor to coil packs...stilll good. now back to square one.

sr23det

the math doesnt add up with out the triggering signal ie ecu,ignitor. you dont have to be a sr20 expert to understand a basic ignition setup

sr23det

also dont forget to check your cas

army240

Ok, let's explain how the ignition system on the SR20 works.

In accordance to have spark, you need the following :

Constant power to the ECU (Pin # : 46, 109)
Switched Power(ignition) to the ECU (Pin # : 38, 47)
Ground to the ECU (Pin # : 13, 39, 48, 107, 108, 116)

Ok, those are the basic to make the ECU “work”.

Then when you crank to engine, the CAS send a signal to the ECU that tell him : "Hey, dude, i'm now at TDC of cyl # 1! Give some fuel and spark Mofo'!"

So to give spark, the coils need : 12V+ Power(Pin #2), Ground(Pin #1), and a switched ground(Pin #3)(this is the one that "trigger" the coils and make the spark, via the ignitor). (Pinout I gave is directly on the coils connectors)

To complicate the thing a little bit, Nissan decided to use an ignitor chip, which is basically just 4 transistors in a nice box. Each coil is connected to a pin of the Ignitor which is named A, B, C, D. Coil # 4 is Pin A and coil # 1 is Pin D, I let you figure out the 2 others (lolz). On the other side of the ignitor, there is 5 pins(1, 2, 3, 4, 5). Each one of those is connected to the ECU except for pin 3 that is connected to Ground. Pin # 1 of the ignitor is connected to pin # 1 of the ECU, Pin # 2 of the ignitor is connected to pin # 2 of the ECU, Pin # 4 of the ignitor is connected to pin # 8 of the ECU, Pin # 5 of the ignitor is connected to pin # 9 of the ECU. Like I said earlier, pin # 3 is connected to chassis ground(pin 13 of the ECU)

Sooooooo…, each time the CAS tell to ECU which cylinder is at, the ECU ground the corresponding pin (either 1, 2, 8, 9). When a pin is grounded, it trigger the transistor in the ignitor, which trigger a coil, which create a spark! Easy right!?

So, knowing those basics… let’s do some diagnostics. What could create a no spark condition on all plugs? Either : no voltage at the ECU, no voltage at the coils, no ground to the ECU, no ground to the coils, no ground to pin # 3 of the ignitor or no CAS signal going to the ECU.

Phew! That's a lot of info there!

I hope that will help!

Frank

MidnightOil

ive done my own testing i have only cylinder one firing

the coils are fine i tested them all on cylinder 1
on the wiring to all the coil they all have ground and have 12v
but i can tell if they are triggering i put a test light on cylinder 1 trigger and it seems like it flashes off with the firing of the spark plug

but not the other three

im a little lost what my next step should be

MidnightOil

ive done my own testing i have only cylinder one firing

the coils are fine i tested them all on cylinder 1
on the wiring to all the coil they all have ground and have 12v
but i can tell if they are triggering i put a test light on cylinder 1 trigger and it seems like it flashes off with the firing of the spark plug

but not the other three

im a little lost what my next step should be

Kingtal0n

classic symptom of incorrect ecu vs harness. You have a J4 ecu on an E5/62 harness or the other way around, it will spark just cyl1 and not the others.

Also, Naturally Aspirated sr ecu will do the same thing sometimes.

I think the ECU is incorrect. Google'd my pinout "J4 to 62" and check your wiring.
http://www.freshalloy.com/showthread...S-Pinouts-here!

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cotbu

I agree but still dont know why these are yours even though i seen you say it many time.

I agree that its a common symptom, of running the wrong ecu. J4 on e and 6 series harnesses.
Ps i remember making 2 types of ecu pinouts. 2 types of mafs pinouts as well. But eh?!

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