No Spark at Cylinder 1

[ninety1two40]

Ok I got RB25DET S1 and I am not getting spark at cyl 1. This is what I have done so far:

1) I have spark at all other 5 cyls (I have a spark gap tester thing)

2) I swapped coil packs with another cylinder, still no spark at Cyl 1. Coil pack works with other cylinders.

3) I pulled the coil pack harness and checked continuity with a multimeter, and the harness doesnt seem to have any poor connections or crap wires.

4) I checked the continuity from the ECU to the igniter plug for the cyl 1 signal, thats good.

5) I swapped the igniter chip with another, same problem. I tried testing the old igniter and the cyl 1 output gives me a diode voltage reading of about 1/2 of what the other outputs give.

6) When the ignition is on and the engine off, and the igniter chip unplugged, i get 12V at the trigger wire (pin 1) at each coil, and 12V at the white wire (pin 3?) at each coil, and continuity to ground at pin 2? (black)

7) My mulitimeter also has the ability to measure frequency so.... at my ECU cylinders 2-6 show about 700-900Hz at idle. Cyl 1 shows about 100Hz less than the others.

At the coil packs cyls 2-6 read about 50Hz and go up with the rpms. Cyl 1 shows about 60-70Hz and jumps up and down with the rpms, its not getting a clean signal or something. Cyls 2-6 frequency rise smoothly with the rpms, cyl 1 doesnt.

I think that is everything I tested. Any ideas? Maybe one of you guru's know something else I can test? I still have to test the output frequency from the ECU when revving the motor, maybe that will give an indication of a problem with the ECU.

Thanks in advance!,Steve

EDIT: Cylinder 1 spark plug is wet with gas. I talked to Carl H and he mentioned it could possibly the ECU.
Modified by ninety1two40 at 1:04 AM 8/3/2007

[gawdzilla]

nice troubleshooting details.

seems like you've tested everything but the ECU. try borrowing someone's and give that a shot.

[Reaper]

I had the same problem, check your ecu, i replaced my factory ecu with apfc and it works perfectly. if you don't hav ethe cash flow to get the pfc just try to borrow anothe factory ecu from someone or buy another one.

[blurrbosi]

I think turbo corey has an oem s1 ecu for sale.

[ninety1two40]

Thanks for your help guys! I don't know anybody around here that has a RB25 ECU I can try out, so I emailed turbo corey to see if I can buy his.

I'll let you know if the ECU was the problem.

Thanks

[Reaper]

I hope that helps! Keep me posted on this!

[ninety1two40]

Ok problem solved....

1) It wasn't the ECU....of course I bought one to figure that out.

2) The trigger wire for the coil pack (the same one that has the loop to time from) was somehow incorrectly wired in my harness. According to the ECU wiring diagram, the cyl 1 wire on the ECU (pin 1) goes directly to the igniter module then from there to the coil pack. But in the stock coil pack harness the trigger wire for cyl 1 is spliced into the same color wire that goes to the 2 pin gray power connector next to the igniter module, this wire showed 12V. I cut that splice, now everything seems to work.

6 cylinders is WAY faster that 5.... holy sh*t!

Also for timing.... I have an Actron (advance auto?) inductive timing light. And I have an old style timing light that has be directly connected. Both work and show the same timing. The newer, inductive timing light has to be clamped on the wire loop in a certain direction, the opposite direction showed double the timing degrees.

Thanks for all you help guys!

[Shocker]

haha good to hear!

[Carl H]

interesting wiring scheme...wonder how that happened.

[ninety1two40]

Yeah I spent alot of time wiring the harness myself to make sure I didn't have any issues... This is the only problem I had so far with it. I'll have to go through the wiring diagrams and all my notes to try and figure it out.