No, bad checksum will not brink an ECM, at least not OBD1 ECMs.
No, checksum is only updated when the bin is saved. This is why checksum needs to be disabled during emulation.
So are you saying that it runs on base timing, but not when timing is being commanded by the ECM?
The man who says something is impossible, is usually interrupted by the man doing it.
Correct. that's what I believe is occuring. Where I'm getting confused is this happens regardless of what bin you use. Even a factory unmodified bin that never hits tunerpro, just straight to the prom, gets you a flickering light.Originally Posted by Six_Shooter
Same with emulation. The one exception; in beginning an emulation session, disabling checksum gets you no CEL, but what I perceive as the base timing only issue. With the flickering light, you don't even get the stumble.
I've got WB02 wired in, otherwise a fairly solid/stock wiring harness throughout the car. I would blame my chip burner, seeing as how you get the issue bypassing TP, but I can't get through with emulation either.
Possible electrical? what would (if anything) invoke this ECM behavior if it electrical and not in the bin/hardware?
First test, and best. Key off for 30 seconds or more. Then turn key on but do not start car. CEL shoould light for 5-10 seconds, turn off for several seconds, then turn on and stay on. If this does not happen then you shouldn't bother trying to start the engine. This test indicates the PCM is able to execute code, the code is working, and the checksum is not incorrect (or engineering mode is active). If the light behaves as expected you should stop chasing checksum/bin/ecm issues.
For my own curiousity, did you modify anything in code for the 3 BAR MAP? Using 3 BAR MAP with an unmodified 2 BAR calibration can produce bad results such is vastly incorrect timing and fuel values for the engine.for what it's worth, it's a 1989 Corsica hatchback. Five speed swap, LG5 turbo. LS springs, roller rockers and it's got a three-bar map in it. '730.
Apologize for the gap in time, I've been away for the Easter holiday..
I've gotten back at it, got the noid light set out. I get one flash of the noid light whenever you first turn the key on and crank. Injectors then have no pulse. I unplugged the injector harness at the back of the upper intake, and ran the noid light pre-injectors via a little engineering. Same result, one quick flash, nothing else there after. This points to a wiring issue, no?
I'm going to get out there again first thing in the a.m., start checking the harness over, with the multimeter. Its a healthy harness, and I see no breaks or shorts. I guess I'm not convinced it's still not in the .bin I'm running
I would put the appropriate map sensor with the appropriate tune. My connector is modified to fit all maps.
Update. Strong voltage at the injectors, no short to grounds I can find.
Also, I discovered when you crank it for extended periods of time, every 5 or 6 seconds you'll get one injector pulse, this is straight from the harness, injectors disconnected. When you test it through the injector connectors themselves, same result. They're just not getting decent signal from the ECM.
Before I throw the ICM and CPS under the bus, not only are they both brand new, well fairly new, but I replaced the ICM with a known good one with the same results. And I'm getting RPM readings on the dash and through tunerpro, I'm just not getting injector signal.
On that note:
These past two days I've noticed something new, I simply cannot get my data stream working correctly. It connects and then disconnects endlessly, but when it connects you get a few seconds of data that seems to be correct. I've triple checked my tunerpro settings, my plug, connections in USB locations. It starts with an error 1 on tuner pro and will literally climb into the thousands cycling in and out of data.
Im still entertaining the idea of a bad part or wiring issue, but I am just convinced it's got to be something in the tune I cannot find any other issue, and I'm running out of things to test
Have you tried disconnecting the TPS on an engine start attempt?
The man who says something is impossible, is usually interrupted by the man doing it.
Yes, and there was no change.
However, after working through my computer and deleting a wireless printer that was taking up all of my comm slots, (emulator and the extreme ALDL we're running on comm 17 and 18 on the laptop), I have recovered all data acquisition, and the emulator is working great from what I can tell.
A few quick mentions before I dive in again, I have a personal salvage yard. I went ahead and threw in three different coils that were known to be good and tested good, a different ICM, which would be the third one, but I have that kind of luck. and it's here. I wouldn't purchase these things to throw parts at it. I just have plenty of everything on hand.
I feel like I may have lost a few of the followers, so let's recap.
I have covered all hardware, twice over on this car. Healthy wire harness, ohm meter shows no shorts on any of the ECM wires (I've found), I'm so in-depth in this issue that I've checked most to make sure that it wasn't being shorted ANYWHERE. All six injectors ohm out perfectly, 36lb for reference. At the beginning of this issue I threw in a brand new crank sensor that I had on hand and never used. As well as an extra crank sensor wire that I had stored, ran it under the oil pan and just bypass the one that is looped through the valley. I've covered all of the wiring and hardware, and parts have been interchanged to no prevail, again because they're here.
So regardless of the ICM I have installed, whenever I have the noid light set hooked up, I will get a bright flash initially, sometimes the engine will stumble and try to start, but the recurring flashes are dim and intermittent. After doing a test for spark, currently the prevailing issue is I have spark but it is intermittent.
Ex; You'll see spark, and then for a revolution you won't see a few, and then for three revolutions or more it will be perfect. And then you'll lose spark for six revolutions and then it'll come back for two, you get the point.
Intermittent spark loss. Intermittent injector pulses. I don't want to be the person that dismisses all suggestions, but I've been through four known good ecms, a few different proms that are eligible to run my setup, with flashable chips installed. Matching map sensors to each mask, one bar all the way up to three. This issue prevails regardless. I'm becoming more and more confident in the vehicle should run with the tune setup, everything seems to be set right with timing. In which may force me to look elsewhere for assistance.
I have currently stopped experimenting with other masks, I'm on 59, 3 bar map. I think I've proven that this issue is going to prevail regardless what I do, tune wise.
I understand that the readers cannot be here to observe the vehicle, but I can almost bet a million that I've tried most suggestions. And I've built this car from the ground up, so me reaching out to people who don't know the vehicle shows how desperate I am. So I guess at this point if this forum will still benefit this issue in any way, it'll be someone having a similar issue in finding a short or something somewhere that is easily overlooked, that I've missed. I suppose it is possible that it's something I'm uploading inaccurately into the emulator, but I've even been on the phone with moates support. So I don't know, if anyone else has any more to add to the thread I'd be honored to read it. And as soon as I fix the problem, I'll update this post. Thx
Adam
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