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Thread: Well it just died.

  1. #1
    Fuel Injected!
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    Well it just died.

    So, I was closing in on the tune, making real progress when all at once it seemed like the engine went pig rich and then it quit starting. I threw up my hands and went to work on the brakes instead, then a tree the wind blew down, other things like that, and tried to get caught up on the home front. Now I'm back at it.

    So, after some testing, checking fuel pressure and such I've determined that I don't have any spark outputs on the car. Put the controller on the simulator and it looks just about like it should so it doesn't seem to be the controller. The check engine light comes on so there must be power, but I'm not showing any codes, though I had no issues with the cheapie Autozone code reader.

    Anybody have suggestions for the first places to look?

    Jim

  2. #2
    Fuel Injected!
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    Didn't really expect a reply, this was as much to get me motivated as anything. But it has continued to get stranger. So I checked for spark and have none apparently. (One spark plug checked in daylight, after dark will be a better test) Do have voltage and grounds going to the coils. Checked the CKP and CMP and have signals there on the ECM connector. ECM outputs power and ground to the sensor also. It seems clear the ECM has power.

    Oh, and it's a '411 P01 ECM.

    My next step will be to check the spark outputs on the ECM. The ECM does have power, I have tried rolling back to an earlier known good tune, and tried a different ECM.

    Jim

  3. #3
    Fuel Injected!
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    Fouled spark plugs, I bet.

    Rick
    1970 Chevy El Camino, LM7 Engine, 4L60E - Two 896 and two 0411 PCM's

  4. #4
    Fuel Injected!
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    Interesting thought. I didn't think it was running rich enough to do that but I pulled the #1 plug anyway. It had a little soot but wasn't pure black. About like it'd be if you were running with the choke on and switched off. From experience I'd say not enough to kill the engine or keep it from starting. Couldn't see any spark on it and couldn't see any with a freshly beadblasted plug. But I'll check again after dusk. May even get my son to crank it while I hold the plug. Risky and potentially painful but a dead certain test.

    No, I think the problem is with the spark output and here's why. I have a spider rig with diodes that I can plug into the coil plugs and look at a trace while cranking and I'm not seeing pulses. But when I bring the ECM in and put it on the simulator and run it, I get a pulse train for the spark outputs. Which tells me that there is something different between the simulator and the car. Something that will turn off the spark outputs. But for the life of me I can't seem to figure out what would do it. I checked the VATS, I checked CKP and CMP, it has power, what else does it need?

    Jim

  5. #5
    Fuel Injected!
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    The coil fuse might be blown. Did the injectors get pulsed on cranking. If you get injectors pulsing but no spark, the ckp signal should be good. Can you monitor the rpm signal at cranking to confirm the ckp is good enough.

    One last reason could be the tune is set for single coil output, or all of your coils got fried at the same time.

  6. #6
    Fuel Injected!
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    Here's the sort of thing that has me questioning my sanity. I went out and put my analog meter on one of the injector plugs, I figured that'd be better than a noid light right? So I was measuring 5v. WTF, over? And it never dropped off. So I tried it with the injector plugged back in and it dropped to around zero. This is the injector circuit self test maybe? It did NOT rise to 12v when the key was switched on, or while cranking. This has to be some kind of progress.

    Since the ECM appears to all indications to be properly loading the OS and tune (under HPT), I think maybe it is time to download the latest few versions of it using PCMHammer and do a clone on the spare ECM, then have a fresh look in TunerPro and see if I can't get pcmscanner to work. So far I haven't found the coil setup in HPT.

    All of your advice and encouragement is invaluable. I could never make it on my own.

    Jim

  7. #7
    Fuel Injected!
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    I have power to the injectors. The controller is not switching. I will check the power and grounds to the ECM and then recheck the CKP and CMP.

    JIm

  8. #8
    Fuel Injected! brian617's Avatar
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    Quote Originally Posted by Jim Blackwood View Post

    No, I think the problem is with the spark output and here's why. I have a spider rig with diodes that I can plug into the coil plugs and look at a trace while cranking and I'm not seeing pulses. But when I bring the ECM in and put it on the simulator and run it, I get a pulse train for the spark outputs. Which tells me that there is something different between the simulator and the car.

    Jim
    You've answered your own question here. Something in the car harness has went wrong. Broken ground?
    89 K1500 Scottsdale 5.7L 5spd 3:42 RamJet cam Dart iron TBI heads 427 PCM swap
    95 C2500 Cheyenne 6.5L turbo diesel 4L80e 4:10 DB2-4911 Manual pump conversion 0411 PCM trans control 2Bar COS
    05 Outback XT 2.5L turbo gas auto

  9. #9
    Fuel Injected!
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    Yeah that thought occurred to me. I go through patches of fog from time to time but it's beginning to make a little more sense the last couple of days.

    Yesterday I put a new connector on the new ignition switch and today I plan to thoroughly test it's functions. Might have had an issue there, it's why I changed the switch in the first place. Unfortunately it isn't a simple plug-n-play so errors can creep in. There are redundant grounds on the ECM but that gets checked next. Plus I plan to compare the main and spare controllers on the simulator for any discrepancies (the spare is a clone so they should be identical) and after that roll back the spare 13 days and see if either one will start the car. Again.

    Going back to the initial failure, indications were that the engine went rich but continued to start for a short period before it wouldn't anymore. Sounds like fuel fouled plugs but what was the beginning cause? Also once they dried it should have started if that was it. But it looks like one step should be to beadblast the new plugs and clean them up. And I could have read the situation wrong. Could have been misfire for example. With a distributor I would suspect the distributor might have moved. So the timing advance needs checked, the injector outputs as well, my AFR traces never were quite right, and none of those looked ideal on the simulator last time I noticed. But, I've also gone back to the original 2-bar tuning file without being able to fire it off so it doesn't seem to be a simple error in the tuning file.

    It looks like a ground-up troubleshooting session is in order, Gotta love it. What the heck, it's only time effort and money right? Of course we all have plenty of that.

    Jim

  10. #10
    Fuel Injected!
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    Logging with hptuners will give you a good idea of ckp and cmp signals. You need to see valid rpm signal and possibly some flags that cmp is present.

    Also check if the pcm is getting ign on signal and crank on signals, from ignition switch. It might just doesn`t know that ign is on.

  11. #11
    Fuel Injected!
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    I want to thank you guys for helping me stay on track, as I tend to get distracted and go off down blind alleys. But a milestone is passed, we have ignition. Not that it ran anywhere near acceptably but it should now be possible to backtrack and find a good re-starting point.

    You'll want to know how. The vehicle wiring harness is aftermarket, Advance Autowire and very high quality but it does deviate from factory color codes a bit. Particularly in the ACC and IGN wires coming off the switch. And since replacement switches use OEM code (usually but sometimes OEM code for other vehicles that use the same switch) there was a switcheroo. But that's not all. I also found a blown fuse, it was the 5A fuse for the ECM. But wait, there's more! The old switch had become intermittent. Not only that but the old switch connector which was a cannibalized Ford sealed connector had inadequate crimping on some of the terminals due to the oversized wires used on those circuits (early AAW, later ones used smaller signal wires.) So with those 4 things popping up in the wake of a series of tuning changes in the wrong direction, you can see how this might get a little confusing. I haven't a clue when or how the fuse blew, it seems fine now. The radio is back on the ACC position, and the main ECM relay now stays hot during cranking as it should. It didn't start easy or run well, and it's far too late to recall what I was doing when that happened but if nothing else I can back up 2, 7, or 13 days to a prior effort.

    I'm happy with today's progress. Heck, I'm ecstatic! I think I'll spend the rest of the day cleaning the shop.

    Is there a wire that tells the ECM when the starter is cranking? I don't remember seeing that.

    Jim
    Last edited by Jim Blackwood; 08-20-2020 at 10:25 PM.

  12. #12
    Fuel Injected!
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    A really bad sequence of events with overlapping and wait there is no spark. Glad you figure it out.

    I am sure there is crank signal going to pcm but not sure which pin. It is on only with ign switch on crank position.

    Edit:
    It is present on 1mb pcms pin59-c2, 512kb migth have but it is quite sure. Most of the diagrams I checked don`t have it.

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