jbtvt

The '85 was misfiring right at the end of last season before I parked it, loaded it up with Star Tron and left it for the winter. The other day I was hoping to drive it a couple hours to my new place but forgot how bad it was running. Pulling wires narrowed it to cylinder 3, plugs checked out but swapped anyway, same problem.

Ordered in a new injector from G&R Reman Beck Arnley which turned out to not be a Denso but decided to use it anyway. Opened her up and found my #3 injector like so:



"Sweet, that must be it then!" Changed #3 injector, scrubbed large rust deposits out of my fuel rail and lacquer deposits out of my damper with carb cleaner and pipe cleaners, swapped the fuel filters and bolted it back up, same symptoms.

Today put a stethoscope on all injectors and new #3 wasn't clicking. I tore it down again, checked resistance - 4.3 ohms, same as the old one. Hooked up an analog voltmeter and a helper cranked it but was getting no jump on the needle with the new or old injector and couldn't hear anything with the scope. Is there some reason I wouldn't be getting a circuit with the fuel pump and/or AFM TPS disconnected, or only one injector hooked up? Do they all have to be connected for the ECU to fire? Odds of having two dead, new and old, injectors slim to none? (Thinking now I should've tested a known good one but it was sleeting and my helper was cold. So was I.) I need to get this thing in my garage now that I finally have one but don't want to drive 2.5 hours with a misfire.

Opened up the harness, splices looked good and were still tight. Broke down and bought a noid light but I don't see how this will tell me anything that an analog VM or scope won't, hope it's worth the $40. Anything else I should look for next trip over?


Side question - intake on my #1 cylinder is pretty sooty, 2 was better, 3&4 were clean. With EGR at the back I would've thought it would be the other way, any ideas what could be causing this?

Terrys87

iTrader: (1)

The fuel systems get dirty in these. Your crimps can be solid but still corroded enough to not let enough current to fire the injector. https://www.yotatech.com/forums/f116...t-22re-270857/ If the noid light is firing check the crimp. I experienced the same thing. I have also experienced bad injector connectors.

Your AFM wire has to be connected and the air tube connected to the Plenum. I have had the wire to the AFM connected and then prop the flapper open for test. When the motor is cranking, it moves the flapper when in turns engages your Circuit Opening Relay (behind Passenger speaker) which then engages your Fuel Pump.

I have seen Intakes about the same or worse then yours, not sure why that is what happens on some cylinder and not others.

jbtvt

Well, the verdict is in and my reman fuel injector was bunk! It was actually a Beck Arnley, G&R was for my LS400 I also just did, my mistake earlier. Anyway, after tracing the wires, checking continuity from pre-splice to the injector pins, confirming signal with a noid light, and coming up empty with why the new injector wasn't firing, I swapped it out for my cleaned out old injector and reassembled. Fired up and purred like a kitten.

Thanks Terry for the reply. I mistyped earlier, I was thinking of my TPS being unhooked, I didn't touch the AFM. So many sensors... I finally figured out why I wasn't getting a signal with the voltmeter before - the ground wire between cylinders 3 and 4 on the intake has to be connected for the injectors to fire! I ran through all possible combinations with the noid light and drained a battery, still not getting any signal. Finally, after connecting that ground it worked flawlessly, althoughly dimly with the low-volt injector signal. The plenum doesn't need to be hooked up to the intake, the TPS does not need to be connected, not does the fuel pump have to be wired for the injectors to fire during testing.

Terrys87

iTrader: (1)

Glad to see you got it running. I use a 9 volt battery, syringe, hose, and fuel injector cleaner to test if an injector is operating. I mentioned on the $3 noid thread about the ground wire needing hooked up and put it on the first post. Glad you mentioned that for the next guy that may need it.