iamshane123
11-15-2014, 10:15 AM
As a disclaimer, I am not well versed in Nissans. At heart, I am a Honda guy (let the flaming begin haha) and I have been working on cars for 10+ years. In addition, I do automotive wiring for a living at the local Sheriff's Department, and though I would not consider myself a wiring guru, I am pretty proficient at it.
With that said, I am at a loss right now. This issue of no spark is throwing me through a loop. Hopefully somebody can point out something that I may have just overlooked. Below, I will outline the steps that I have taken to troubleshoot this issue.
My buddy is doing his sr20 swap into his 91 hatch. After setting the new motor in and modifying the harness according to the frsport write up (extending the leads for the MAF and o2 sensor, as well as swapping the KA harness dash connector and the 2 KA chassis harness connectors behind the passenger headlight onto the sr harness), we attempted to start up the vehicle and no luck.
We came to the conclusion that there was either no fuel or no spark. We eliminated the possibility of no fuel but did find out that we were only getting spark on 2 cylinders (1 & 3) and it was very weak on cylinder 3. After using a meter and testing the wires at each coil and comparing the readouts to a running sr swapped I noticed they were the same as the running 240. Tracing the wires back even further, I found that the 5 pin side of the igniter chip was not reading out like the running one. So just to verify, we swapped the igniter from the non-running to the running and the running one started up just fine eliminating the igniter chip as the culprit. We then swapped the coils from the non-running to the running and it started up fine, eliminating the coils themselves. Then, just to be sure, swapped the ecu (E5) from the non-running to the running and still it cranked up and ran just fine.
After these tests, it lead me to believe that the only thing that could still be an issue is the wiring. I pulled the wiring back from the ecu back through the firewall and began to check the pins against a pinout diagram. Sure enough, I found that 3 of the 4 ignition coil signal wires were not in the right pins; and I didn't just trust the colors of the wires, I actually ohmed out the wire from the ignitor connector to where it pins into the ecu. I should also mention here that it is evident that somebody has done some altering to this harness previously as there are some less than quality splices and connections throughout the harness so the fact of some wires being in the wrong pins was not too surprising. After swapping the ignition coil signal wires to the correct pins (1,2,8,9) I thought for sure this would solve the problem. Only ignition signal 1 was in the right pin while ignition signal 3 was in pin 3 (tachometer signal) and signal 4 was in pin 5 (unused) and I don't recall where signal 2 was.
Plugged the ecu back in and checked the 5 pin side connector of the ingnitor chip and everything seemed correct. Tried to crank...and nothing. In fact, now I'm not even getting spark on any coil. :picardfp:
Unplugged the ecu again and decided to go through every single pin to check for accuracy and ohmed out everything that I could to ensure it was the right wire. Ended up finding 4 or 5 more wires in incorrect pins so I went ahead a swapped those around too, though nothing that I can really see causing an issue with spark.
The only issue that I found on the ecu pinout that could maybe be causing any problems is with the CAS 1 degree signal.
CAS 180 degree signal has 2 pins on the ecu (22 and 30) which tie together to one wire about a foot up the leads. I see from the pinout diagram that there is also 2 pins on the ecu (31 and 40) for the 1 degree signals. However, I only have a lead coming from pin 31. Nothing is in pin 40. Now I assume that just like the 180 degree signals, the 1 degree signals would normally tie together to one wire too.
Could this be a root of any of the problems of no spark? Does the ecu perhaps need 1 degree signal coming to both pins to let the ecu know which cylinders to be firing? Or could at least not having that signal put the ecu into a limp mode or something? I'm stumped for now.
So as a quick recap:
Coils are good
Plugs are good
Igniter Chip is good
ECU is good
Re-Pinned Ignition Coil Signal leads to correct pins
*Missing CAS 1 degree signal at pin 40
Here is the diagram I was using...
http://www.s-chassis.com/resources/wiki/images/6/60/ECUS13SR20DET.jpg
With that said, I am at a loss right now. This issue of no spark is throwing me through a loop. Hopefully somebody can point out something that I may have just overlooked. Below, I will outline the steps that I have taken to troubleshoot this issue.
My buddy is doing his sr20 swap into his 91 hatch. After setting the new motor in and modifying the harness according to the frsport write up (extending the leads for the MAF and o2 sensor, as well as swapping the KA harness dash connector and the 2 KA chassis harness connectors behind the passenger headlight onto the sr harness), we attempted to start up the vehicle and no luck.
We came to the conclusion that there was either no fuel or no spark. We eliminated the possibility of no fuel but did find out that we were only getting spark on 2 cylinders (1 & 3) and it was very weak on cylinder 3. After using a meter and testing the wires at each coil and comparing the readouts to a running sr swapped I noticed they were the same as the running 240. Tracing the wires back even further, I found that the 5 pin side of the igniter chip was not reading out like the running one. So just to verify, we swapped the igniter from the non-running to the running and the running one started up just fine eliminating the igniter chip as the culprit. We then swapped the coils from the non-running to the running and it started up fine, eliminating the coils themselves. Then, just to be sure, swapped the ecu (E5) from the non-running to the running and still it cranked up and ran just fine.
After these tests, it lead me to believe that the only thing that could still be an issue is the wiring. I pulled the wiring back from the ecu back through the firewall and began to check the pins against a pinout diagram. Sure enough, I found that 3 of the 4 ignition coil signal wires were not in the right pins; and I didn't just trust the colors of the wires, I actually ohmed out the wire from the ignitor connector to where it pins into the ecu. I should also mention here that it is evident that somebody has done some altering to this harness previously as there are some less than quality splices and connections throughout the harness so the fact of some wires being in the wrong pins was not too surprising. After swapping the ignition coil signal wires to the correct pins (1,2,8,9) I thought for sure this would solve the problem. Only ignition signal 1 was in the right pin while ignition signal 3 was in pin 3 (tachometer signal) and signal 4 was in pin 5 (unused) and I don't recall where signal 2 was.
Plugged the ecu back in and checked the 5 pin side connector of the ingnitor chip and everything seemed correct. Tried to crank...and nothing. In fact, now I'm not even getting spark on any coil. :picardfp:
Unplugged the ecu again and decided to go through every single pin to check for accuracy and ohmed out everything that I could to ensure it was the right wire. Ended up finding 4 or 5 more wires in incorrect pins so I went ahead a swapped those around too, though nothing that I can really see causing an issue with spark.
The only issue that I found on the ecu pinout that could maybe be causing any problems is with the CAS 1 degree signal.
CAS 180 degree signal has 2 pins on the ecu (22 and 30) which tie together to one wire about a foot up the leads. I see from the pinout diagram that there is also 2 pins on the ecu (31 and 40) for the 1 degree signals. However, I only have a lead coming from pin 31. Nothing is in pin 40. Now I assume that just like the 180 degree signals, the 1 degree signals would normally tie together to one wire too.
Could this be a root of any of the problems of no spark? Does the ecu perhaps need 1 degree signal coming to both pins to let the ecu know which cylinders to be firing? Or could at least not having that signal put the ecu into a limp mode or something? I'm stumped for now.
So as a quick recap:
Coils are good
Plugs are good
Igniter Chip is good
ECU is good
Re-Pinned Ignition Coil Signal leads to correct pins
*Missing CAS 1 degree signal at pin 40
Here is the diagram I was using...
http://www.s-chassis.com/resources/wiki/images/6/60/ECUS13SR20DET.jpg