S14 sr20det no combustion first and second cylinder HELP!!!! - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

deathb4dishonor · 01-03-2017, 06:03 PM

I usually never post cause I like to do a lot of research and fix things before they ever become a real problem but this is not the case. I recently bought a s14 kouki with a s14 blacktop sr20det swapped in. The motor has got me stumped and I'm at the end of the line with this one. So motor runs rough, misfires and has no power in and out of boost. I already compression tested and replaced TCS, spark plugs and battery, redid the grounding straps and tested every sensor and harness in the engine bay. The first and second cylinders are definitely the problem, I found that out with my consult and Nissan data scan(full version) that cutting off first and second cylinder make no difference and that this entire time iv been running off of 2 cylinders number 3 and 4. I confirmed by power test, removing each coil pack no change except for cylinder 3 and 4. Same with injectors pulling 1&2 no chang.
The thing that doesn't make sense is I have fuel, spark and good compression. All 4 coil packs test good and iv swapped them with no difference. I tested the cas, injectors and ignitor all tested good according to FSM. Redid my timing iaw fsm. All wiring including coil pack, injector and ECU harnesses and they all test good. I am really stumped and don't see how this is even possible. The only thing I can think of is the ECU is bad, but I have no ecu fault codes (55) and I have no problem communicating with consult and NDS software.
Please if anyone has come across this problem if they could share some incite I'm drowning here thanks in advance.

gaz_moose · 01-04-2017, 03:59 AM

how can you have fuel and spark to those cylinders and not get ignition?

its either fuel or spark related.

is the cas fitted correctly? is it timed upto 15 deg TDC etc..

jr_ss · 01-05-2017, 04:00 AM

Have you actually done a compression test to confirm you have compression?

deathb4dishonor · 01-05-2017, 10:38 AM

solved it, it was a weird mix of weak spark and spark plug gap. replaced the ignitor and plugs now it idles and runs better. the crazy thing was that It was getting 12v to the coil pack intermittently to cylinder 1 and 2 but constant with 3 and 4. Doesn't seem possible since the ignitor supplies 12v to all coil packs but it fixed it with a known good one thanks for your help guys

deathb4dishonor · 01-05-2017, 10:45 AM

Also, one more thing to anyone else that may have this problem I tested the ignitor in accordance with full-service manual procedures and it tested good but I believe that the internal diodes and circuitry gave off false readings to indicate a good ignitor even though it was defective causing weak spark on coil packs one and two but not three and four. So borrow an ignitor and test it out you never know.

01-03-2017, 06:03 PM	#1
deathb4dishonor Join Date: Apr 2015 Location: SA Posts: 10 Trader Rating: (0) Feedback Score: 0 reviews	S14 sr20det no combustion first and second cylinder HELP!!!! I usually never post cause I like to do a lot of research and fix things before they ever become a real problem but this is not the case. I recently bought a s14 kouki with a s14 blacktop sr20det swapped in. The motor has got me stumped and I'm at the end of the line with this one. So motor runs rough, misfires and has no power in and out of boost. I already compression tested and replaced TCS, spark plugs and battery, redid the grounding straps and tested every sensor and harness in the engine bay. The first and second cylinders are definitely the problem, I found that out with my consult and Nissan data scan(full version) that cutting off first and second cylinder make no difference and that this entire time iv been running off of 2 cylinders number 3 and 4. I confirmed by power test, removing each coil pack no change except for cylinder 3 and 4. Same with injectors pulling 1&2 no chang. The thing that doesn't make sense is I have fuel, spark and good compression. All 4 coil packs test good and iv swapped them with no difference. I tested the cas, injectors and ignitor all tested good according to FSM. Redid my timing iaw fsm. All wiring including coil pack, injector and ECU harnesses and they all test good. I am really stumped and don't see how this is even possible. The only thing I can think of is the ECU is bad, but I have no ecu fault codes (55) and I have no problem communicating with consult and NDS software. Please if anyone has come across this problem if they could share some incite I'm drowning here thanks in advance.

01-05-2017, 04:00 AM	#3
jr_ss Post Whore! Join Date: Dec 2005 Location: Pa Posts: 6,056 Trader Rating: (34) Feedback Score: 34 reviews	Have you actually done a compression test to confirm you have compression? __________________ My SR20VET

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01-04-2017, 03:59 AM	#2
gaz_moose Zilvia Member Join Date: Mar 2008 Location: engerland Posts: 242 Trader Rating: (0) Feedback Score: 0 reviews	how can you have fuel and spark to those cylinders and not get ignition? its either fuel or spark related. is the cas fitted correctly? is it timed upto 15 deg TDC etc..

01-05-2017, 10:38 AM	#4
deathb4dishonor Join Date: Apr 2015 Location: SA Posts: 10 Trader Rating: (0) Feedback Score: 0 reviews	solved it, it was a weird mix of weak spark and spark plug gap. replaced the ignitor and plugs now it idles and runs better. the crazy thing was that It was getting 12v to the coil pack intermittently to cylinder 1 and 2 but constant with 3 and 4. Doesn't seem possible since the ignitor supplies 12v to all coil packs but it fixed it with a known good one thanks for your help guys

01-05-2017, 10:45 AM	#5
deathb4dishonor Join Date: Apr 2015 Location: SA Posts: 10 Trader Rating: (0) Feedback Score: 0 reviews	Also, one more thing to anyone else that may have this problem I tested the ignitor in accordance with full-service manual procedures and it tested good but I believe that the internal diodes and circuitry gave off false readings to indicate a good ignitor even though it was defective causing weak spark on coil packs one and two but not three and four. So borrow an ignitor and test it out you never know.