naru2

If your car was 87 1/2 or newer,I would say the resistor for injector #4 is shorted,but earlier models did not use a resistor pack. Do you have a flapper MAF and distributor equipped w/vacuum advance or hot wire MAF w/optical distributor?

Trace which output pin that transistor feeds.That will tell you which circuit drew too much current. That does not look like an injector driver to me(could be wrong).I would expect the injector drivers to be on a heat sink.Perhaps the problem is elsewhere. Should be no problem running 2 injectors in parallel as that is what the ECU does.3 is a different story.

Are these measurements taken w/both injectors unplugged or both plugged in?

and XTs have 2 more different ones(early and late).not counting the electronic one. According to the parts book,the 3 non XT ones vary by year:85-86,87,and 87 up

Looks like the power transistor on the heat sink (another NEC D1590?) shorted out.Could be an easy fix C401 looks overheated too. I would make sure the injector harness is not shorted to ground before plugging in another ECU.

86&87 XTs use the same ECU whether MPI or turbo according to the parts book-22611-AA073

The spring washer is the same too. 623204080

At the dealer. Part Number: 623024020 Supersession(s): 623024010; 623024011 Same part as EA82s

Check the dimmer switch.The dimmer switch grounds the red/black low beam wire to activate the low beams. There should be power at the low beam connector (red -RH,red/blue LH)anytime there is power at the high beam connector on the same side regardless of dimmer switch position.If not,The harness is broken.

Tee in a pressure gauge or better yet,remove them and apply fuel pressure.

This pretty much proves the plugs are fouled w/fuel or coolant.Probably fuel in your case.Likely a leaky injector .Check them by seeing if fuel pressure holds after shutdown. If the engine revs w/o a response from the car,you have a transmission problem.Check the fluid level etc.

At least one injector is still leaking.Just because they are new does not mean shyte. I have had new ones leak. Prove it by installing a pressure gauge and watching the fuel pressure drop after shutdown or better yet apply fuel pressure to the injectors with them removed. At least one will drip.I put test tubes over the injectors and left them overnight to find the leaker. Holding the gas pedal to the floor w/starting does not "flood it out" It does exactly the opposite.It cuts off the fuel supply.

Steady,but,slow cold idle-correct? I would start by checking the CTS connector for corrosion and the CTS resistance. IAC seems to be working(high cold idle) but would still be worth cleaning.It may be sticky. Check fuel pressure.My own car behaves badly in cold weather if the fuel pressure is a little low,but,it runs fine warm. Be aware that vacuum or unmetered air leaks occur at places other than hose joints.(Unlikely if the idle is steady).

The big black one No ballast resistor on a SPFI Sube.