No ignition on Cylinder 4

[Isofouet]

Hi,

I rebuilt the SR20 of my S15 with a few upgrades, especially a nistune Type 4 board to remap it.

I got no ignition au cylinder 4, the engine runs on 3 cylinders only...

I swapped the coils, but the problem is still on cylinder 4.

So, I plugged a digital oscilloscope to the ECU to check the signals.
The signals for coils 1, 2 and 3 are OK, but I got a weird signal for the #4 coil.



When I crank, there is this constant signal on #4 and not the expected peaks...

What should I check ?

I checked the welding of the nistune board, the continuity is OK, but it's hard to see if the are some parasites...

Thank you

 

[JDM_virgin]

Hi mate, I assume it was running normal before the rebuild? I would probably check the basics if you haven't already done so like leads, bad plug etc. I know it sounds obvious but you'd be surprised how many people neglect the obvious. As for issues with the board or mapping unfortunately I know very little so you will have to wait for some more experienced user to comment but that is where I would be starting. Good luck

 

[S15_SAM]

Give a company called Horsham developments in the UK a call and speak to Jez. He is a Nissan expert and nistune expert. Or email him with the pictures saying you have a problem with a nistune board.

Otherwise its most likely your getting a dodgy signal from the ecu and therefor its most likely the ecu.

 

[Auss15]

I'd say its a problem with the board, the inputs are definitely an issue on 4....

 

[Isofouet]

Yes, I contacted Horsham. My rebuilt engine comes from here.
I have to check the wires, and the grounding, but it seems to come from the ECU.

I've already tried to swap coils and plugs, but the problem is everytime on the #4.

Horsham can't test my ECU.
How can I test if the problem comes from the board ?

Thanks for your answers

 

[Chriscooke]

Is the earth strap from the coilpack loom to the block attached? If it's the same as on the s14's its easy to forget when putting it all back together.

Do you know anyone with a working car?

 

[Auss15]

Use a multi meter to look at the voltage coming from your coil looms..

 

[Isofouet]

Thanks,

I checked the looms. I got the ground on cylinder 4, and it is connected to the condenser to (as the other 3)
I got continuity from the ECU to the coil

So it seems to come from the ECU. I checked for continuity between pins, but found nothing...

I believe this issue won't be simple to overcome...

 

[Isofouet]

It was an ECU problem, Nistune said that maybe a coil driver transistor/diode may be damaged... I had to replace the ECU, it works now !

 

[Auss15]

Glad it was sorted and you got the right advice from the guys here...