4age 20V STA wire

[gjgnz]

Can anyone tell me what the STA wire does on a 4age Blacktop 20V engine? Is it necessary to hook it up for an engine swap? What would happen if the wire wasn't connected?

[Hen]

STA wire is the starter signal. That pin is an input that tells the ECU that you are trying to start and probably uses a special injection time and ignition timing. But if the engine starts then that pin will not have any further effect.

So it's a niceity but not strictly needed.

[wilbo666]

Hen's given a pretty good answer!

But I would really want to ask the question as to why you wouldn't connect it tho!
Pretty sure 99% of engine ECUs take it as an input for a reason

Cheers
Wilbo

[gjgnz]

Thanks for the replies. I'm running an aftermarket loom which doesn't have an STA wire going in to the ECU.

The car starts and idles perfectly but hesitates when the throttle is applied and occasionally backfires out the intake (particularly cylinder 4). I'd seen the STA input mentioned online as a possible culprit but if it only gives a signal when the engine is cranking I can't imagine that would be causing my issues.

[DX20VT]

It basically put it into base timing mode for cranking. Leaving it disconnected does not really cause a problem.
Hooking it up so it has power on it when it should not does cause major problems, loss of power, lack of advance, unable to set the base timing etc.
99% of transplants or rewires I have seen do not use it.