Misfire and unknown electrical issue

[s15uwu]

Hi all,

My Silvia has recently developed a strange problem.

It misfires and runs on 2/3 cylinders all the time its running, except when the key is turned to the off position or removed, it will then run normally for about 3 or 4 seconds before dying.

I have checked that im getting spark on all 4 cylinders, and that im also getting fuel.

Anyone had a similar issue, or has any ideas that can point me into the right direction diagnosing this?

Thanks in advance.

 

[lewis]

seems like a weird overrun! is it mapped, stock ecu or aftermarket etc? cause it could be the timing is off or the ecu has issues

 

[s15uwu]

Stock, with a horsham stage 1a chip.
Might source a stock one and try it in.

 

[hugh janus]

is the Hdev 1a actually for an S15? or is it a 14/14a Rom?

 

[s15uwu]

is the Hdev 1a actually for an S15? or is it a 14/14a Rom?

its a spec s s15 with an s14a sr20det in it.

 

[hugh janus]

who made your conversion loom? or did you re-pin?