Hey all, first post and I’ve gone through all other ports related to injectors not firing and I’ve gone through most of the trouble shooting most posters have done.
I have a 1986 Pickup with the 22RET and I recently replaced my fuel dampener, injectors, soldered on new injector connectors, new fuses, and new vacuum lines. After replacing all these items my truck will start for 1-2 seconds and then die instantly, pressing the gas pedal changes nothing.
i inspected my solders, and de-loomed my harness to look at the fuel injector splices and they look intact. I get 12v from to the connectors from battery, solenoid resistor has a resistance of 3.5ohlms, and is receiving voltage. ECU fuel injector spots read about 12v-ish across the board where they should. Fuel pump turns on when I move my AFM flap, and I’ve replaced most fuses relating to the fuel or EFI. I can hear my Cicuit opener relay click when I turn the truck over and I’m still getting the same result. I have fuel pressure to my cold start injector atleast because I have gas spray out when I turned it over without it being bolted. I’m running out of ideas and could really use some help.

also when I attempted starting the truck with its old falling apart fuel injector connectors I heard a loud “crack/pop” that made my ears ring. Not sure if it was a back fire or if something electrical went out. I haven’t found any burnt wires or burns, but then again I’m unsure where else to look along the efi cicuit.

 

Unplug your cold start injector from the harness, if you can get it started and it still stalls you know the injectors are being triggered and that's not your problem.

The alternative is using an LED based test lamp on the injector harness.

You've most likely got another issue. You say you have fuel but do you have enough volume and pressure. Test the volume returned to the tank with the fuel pump test jumper in place.

Take the return line off the body side hard-line after the regulator and plumb it into a catch container. You should get about half a liter a minute. If you get nothing pull some vacuum on the regulator vac line, this will confirm your fuel supply lines are probably ok. You've got a bad fuel pump confirmation at this point.

If you've got excess fuel returning to the tank, your fuel pressure and volume is probably OK, you've got the classic COR failure. Just because a relay clicks doesn't mean it's good it just means it's getting power and ground on the switch coil.

 

Thank you for the fast reply! I tried starting with the Cold starter disconnected and i got nothing, engine cranks and nothing happens. Took off the fuel return line and got roughly 1/2-1 liter of gas in the bottle while jumping the fuel pump over the course of 1min. Stopped by Oreileys and grabbed a new COR relay and still ended up with the engine firing up for a second and then dying. I'm going to try and check the noid lights tomorrow and see if i am even getting pulse to the connectors. I tested the connectors and am positive i am getting 12v to each connector. If noid lights do not light up, what should i look at next? I'm assuming if i get lights at each of the injector connectors that then it means i have a bad batch of injectors. Thanks again!
1

 

Changing parts like that is frowned upon for several reasons.

How do you know the part you bought wasn't defective? You need to test the systems! For the COR one of these tests is koeo, push open the vane in the air meter and see if the pump runs. Not performing this simple five minute test just cost you money.

There is only one accessible injector plug (#1). If your noid light doesn't fire on this one it's not likely the others will either. You'll need to check for continuity from the injector to the ECU after that. Then that the signal generator signal (NE) is making it to the ECU. Once all those are checked you can consider condemning the ECU..


You need to locate a factory service manual, it's worth the time. There are lots of things to test.

 

Thanks for your suggestions man. I went through and replaced most of the EFI system due to the fact that most of it was deteriorating. Even after all new parts were tossed in, it still didn’t fire them. Took a look at my solder on the connectors and figured out the problem. Turns out I taped the two wire together for some reason. So the negative ground signal couldn’t be sent to the injectors to fire. Separated and wrapped the wires individually and got them to fire. Cost me some money, but the truck fires up and runs more smooth than ever now. Thank you for your replies, I have an online FSM, and now am just being more careful when I do things. Going to refresh the turbo and do some general engine maintenance next, hopefully it goes well. Thank you again!

 

A resistance check between the external resistor harness and ECU in theory would have picked that up. In practice it might have been questionable since measuring low resistance becomes difficult typically, was it a bad probe connection did I touch the tip how good is my calibration..

The RET injectors are wired in pairs. Each injector has a nominal resistance of ~2.5. So you should have 2.5/2=1.25ohms. What you would have measured would be either 2.5 or 0 depending on how many of these you shorted out.

Good deal!