injectors not firing.. again

**91dime** · 02-21-2016

So a while ago my injectors quit firing, after researching, I rebuilt the distributor with a new cap, rotor and ICM. After that everything was running well for a while until it started again. Well I found the clips on the coil were bad and if I unplugged them and plugged them back in, it would fire up no problem. So naturally I got a new harness for it, plugged it in and the injectors won't fire. Not sure where to look next, it's got plenty of fuel pressure going into the TBI. Not sure how replacing 2 plugs would make it not work.

If it's worth anything the injectors are a little wet on the bottom but no drips or spraying. Is it possible for 2 injectors to completely clog at the same time? And how likely is that to happen?

I'm very close to the point of taking all this efi stuff out and throwing a carb on the truck. Iv spent so much time tinkering with this thing just to get it to run decent it's making me bitter. As soon as one thing is fixed something else starts acting up making it a pain to attempt to tune. Sorry for the rant.

Sorry for typos or weird sentence stuff, I'm typing this out on my Android.

**jim_in_dorris** · 02-21-2016

Ohm out the new harness, have to guess you have an open circuit.

**91dime** · 02-21-2016

I should have said pigtails or whatever you want to call it. It's just the 2 new plugs that go to the coil with wires about 6 inches long I had to connect to the existing harness, I tested them with a multi meter and the wires seem to test fine, voltage is going to the coil at the very least. And the one wire that comes from the dizzy to the coil that I can take off, test with no resistance so the dizzy is connected to the coil no problem. I even tried another coil I had laying around and still no luck. I made sure the crimps were strong. To afraid to have soldered wires around an engine block, to many heat cycles may make the solder brittle.

**jim_in_dorris** · 02-21-2016

next test is to find a noid light to see if the ECM is trying to fire the injectors. I just had to replace the connectors to my injectors, they were old and broken. As I drove down the road, they would work loose and the truck would stall. I would get out, plug them back on the injector, and could drive another couple of miles. Rinse and repeat. It got old fast, and the temporary fix only worked for a couple of months.

**91dime** · 02-22-2016

I have not had the chance to get a noid light yet but I did three other test.
First, I used a 9v battery on the injectors and both sprayed fuel no problem with the fuel pump running. So that must mean both injectors are fine.

Second, I tested the positive pins on the injector plugs, both read the same voltage tested at the battery.

Third, I tested the wires that go to the PCM to direct ground and no short. So next I tested the wire at each end to make sure they arn't broken and both test with 2 ohm. Since both read the same I would like to assume they are both fine.

So now I know the plugs are properly connected to the PCM and a 12V source plus the fact both injectors fire when using a 9V battery. Does this mean the PCM may have taken a crap? Or did the new module I put in the distributor fail already? Should I still pick up a noid light knowing now that both injectors work under power and the voltages and wires are good?

**EDZIP** · 02-23-2016

Those noid lights are a must...the only way to determine if your ecm is sending the ground signal since you know you have 12v to each injector. I think even Harbor Freight sells them.

I'm sure you have tried spraying some gas into the throttle body to see if it runs.