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ok, so around 5000 miles ago my truck started running kinda rough and had some random misfires and popped up with a code 18, spout circuit open, I did the check on the wire between the spout and the computer, both resistance and voltage drop, and it tested out just fine. not long after it up and died as it pulled in the yard and wouldn't restart. I had another dizzy/module on hand so I slid it in, it ran better and the code didn't come back.
recently I have had to go back to driving it daily, and the same thing is happening. it starts and runs pk, but sounds a little rougher and seems to have a slight random missfire, every now and then it acts like its going to die before it catches itself and idle's back up, I can notice a lack in power. plus my mileage has taken a huge hit. code 18 is back for the KEOR test. I did a 200 mile all highway trip this weekend and it got 11.8, this is the truck that has typically got over 16 with mixed driving, and I didn't really get to check it before I went to synthetics and installed an underdrive pullley
I did a search and didn't come up with much info other than there was a change from the grey to the black module in the 90's.
I do realize that its possible that the dizzy I swapped in might have just failed, and kinda regret now that I don't know if it was the dizzy or the module. but is there anything other than the ECM that can make them fail? what else can I check to be sure that its not just going to fry another module or dizzy?
i'm really tempted to just toss the bronco's megasquirt on it.
I hit it with the fluke, and its got solid continuity both ways, so I guess I'll be needing another. Now another question. I'm guessing that the diode is there to protect the ecm, so is it possible that it could have harmed the ecm?
any other ideas as to what could cause modules to fry?
today it died at half a block away when i left home, which is something new. it took some cranking before he started to sputter, then finally fired and ran ok. what I find strane about this is that i thought all the TFI problems were heat related? I hadn't even been in the pickup long enough to listen to a song on the radio.
this doesn't really link to code 18, but i found two plugs that were black, #3 and #5. I'm gonna run a compression check to be sure, but I don't really think its oil (less than 100k on reman long block) maybe sticking injectors? it would have to be doing so intermittently, since its not smoking and the missing is intermittent as well.
oh, and ecm caps are fine. and I hate just throwing parts without a diagnosis, but i'm gonna go ahead and drop a new module in it.
ok guys, been driving on this new module, and while it sounds better, code 18 is still there.
the computer is moving the timing around, I tried a few different timing settings, and found one that works a bit better, and I also found an old TSB about plug wires 7&8 being too close together and induction misfire, and rerouting the plugs wires helped a bit. it only occasionally stalls at stop lights now, but power still sucks and im still doing really good to get 12mpg
I also pulled out my stethoscope and listened to all the injectors i could reach, and they all sounded good w/ no oddballs.
If you physically remove the SPOUT does the timing drop back to base and remain there?
Did you ever test the resistance of the SPOUT signal to ground? It's not uncommon for the shield to rub through the wiring on that bundle then ground out the signal.