Recent content by sdryluth

  1. S

    Rough running, stalling, check engine light, and can't pull codes.

    Just an update for anyone that somehow has this same issue in the future. I replaced the ECM and it seems to be working perfectly fine now. All of the issues mentioned before are gone. There was no visible damage to the ECM, but it definitely was the problem.
  2. S

    Rough running, stalling, check engine light, and can't pull codes.

    Well I fixed the wire and fully charged the battery, but it didn't change anything. The CEL still flickers like before, and it still sputters, kicks, backfires, and stalls when warm. Having the battery unplugged cleared code 43 and even after I drove it around for a bit with it kicking and...
  3. S

    Rough running, stalling, check engine light, and can't pull codes.

    The battery was at 12.6 volts, it was just slow to crank because it's -10 degrees here. Your comment brought up an interesting point though, the volt gauge is reading lower than I would expect for 12.6 volts. I took a look at the battery connections and found this. The ground cable going...
  4. S

    Rough running, stalling, check engine light, and can't pull codes.

    I borrowed a scan tool which in theory should have been able to pull live data. It didn't work, but I'm unsure if its an issue with the tool or the truck. I'm inclined to think its an issue with the truck, probably the ECM given the other problems. I took this video of the weird flickering...
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    Rough running, stalling, check engine light, and can't pull codes.

    I did a bit more work trying to figure out the check engine light issue. That diagram I posted before shows that the pin the ECM grounds to turn the CEL on also runs down to Pin D on the ALDL connector. I hooked the scope up to that pin and found that when the CEL starts to flicker, its because...
  6. S

    Rough running, stalling, check engine light, and can't pull codes.

    The above image shows the connections leading to the ALDL port on the 1990 K1500. I checked Pin A and found it has good connection to ground. I checked Pin B and found it has good connection back to the ECM connector. I think this means it should at least be capable of putting into code flashing...
  7. S

    Rough running, stalling, check engine light, and can't pull codes.

    The wiring to the diagnostic connector is fine so I guess it must be an issue with the PCM or the wiring to the check engine light? I'm also not sure if the issue being able to check codes is the same or even related to the engine running poorly, but it does make it a lot harder to diagnose...
  8. S

    Rough running, stalling, check engine light, and can't pull codes.

    Hi there, I have a 1990 K1500 with the 5.7 TBI engine that i'm trying to diagnose. Sometimes it will run just fine, especially when the engine isn't warm yet. When it's up to temp it will often go into this phase where it runs very rough and stalls. It especially likes to stall when coming to a...
  9. S

    1990 K1500 refusing to flash out codes

    Yeah I double checked and i'm shorting the correct pins. I also tried going to another ground and no difference. It runs and drives perfectly fine so I wonder if like you said the CEL being on is some kind of failure. It doesn't blink at all with key on engine off, and the only time the light...
  10. S

    1990 K1500 refusing to flash out codes

    Hey folks, I've got a weird one. My new to me 1990 K1500 has a check engine light on. Sometimes it turns off for a second or two while i'm driving, but it always comes back on. The problem is, I can't seem to get the codes out. Shorting pins A and B on the diag connector together does nothing...
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