Smoked ecm......

NOTSOFAST

Member
I had noticed that sm would go haywire when I would take GN out on short or long cruises. Clear up for a little bit but then go haywire again. SM Lights would blink , go blank then read again. Codes from 42 to 55 would show up. After I cleared the codes, it would drive fine then sm would act up again. Well, today ecm fried. as I took her out for a spin it started doing the same things. When I got home , I had ecm out of side panel. With car on, if I flipped ecm sideways, GN would turn off, if I layed ecm flat on floor board, GN would stay running. After the 3rd time of turning sideways I saw smoked,GN turned of and wouldn't re-start. I switched ecm with GN #2. And GN#1 started right up. Was ecm going bad or do I have another issue? Here is pic of smoked ecm. Did I fry my power logger as well,along with my TT chip?

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SHADOWII

Well-Known Member
I would suspect the wiring to be the problem before the ecm itself. In which case be careful how you handle the 2nd ecm. in gn #1. You could have to purchase 2 ecm's:eek:
Bob B may be able to identify the chip right away, but I have to research it. It looks like it was burned from a direct short. Once the chip is identified, it will be easier to determine if the TT and/or p/l bit the dust.
 

TurboTnZ06

Go on red!
Maybe a loose screw in the ecm? Check wiring as mentioned. I just replaced my ECM (water from cracked open window and rain) got 2 remans from advance auto for 150 shipped after coupons online. Modifying them for powerlogger is easy once you've done some. My power logger was fine after replacing ecm so far so good.
 

TurboBob

Resident mad scientist
Staff member
hard to tell from the pic, but if the ECM fails it can take out the chip and PL.

I would scrap that ECM, and start "fresh". Be careful though, a fried chip or PL can take out your other ECM....

Bob
 

NOTSOFAST

Member
it must have fried the chip and the pl, as after I installed new ecm, same chip and pl adapter, GN is doing the same thing. Except I get no sm readings. I installed a different tt chip and it smoothed out some. So where do I go from here? Order new tt 5.6 alky chip, along with new pl hardware ?

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NOTSOFAST

Member
right before it did this, it threw a code 42. could a bad control modual cause this? I mean if control midual is bad, GN would still act up even with new ecm,right? as i checked ecm wire for rubbed or shorted black/tan wire, didn't see anything. i will swap out control modual and coil pack since they have lifetime warranty. then i'll go from there.
 

NOTSOFAST

Member
ok, after installing new ecm, GN does the same thing. I noticed sm does not read anything. SES light stay on and GN if it starts runs like crap. I have checked for breaks in ecm wires, white/ black - ground to aldl and brown/black wire for ground to ecm. I took wire out of the loom as it looked like they were sitting on down pipe. But a again no breaks in wireing. I have read and re-read the no start procedure and still nothing. I even tried a different chip in ecm and still nothing. Where do I go from here?

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NOTSOFAST

Member
Since the last code it threw was a 42, I have done the trouble shooting for that and still nothing. Could chip and new ecm be bad?

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SHADOWII

Well-Known Member
Have you made any progress w/your problem? I haven't any info on the chip that burned. The new ecm, did you connect it w/the possibly damaged p/l ? Have you verified your fuel pressure, voltage, checked plugs for wetness, tps, etc. Please describe the "crappy performance" a little more precise.
 

RmvBfrFlght

Well-Known Member
The chip that fried is the micro-processor. The 185 ID's it as being manufactured by Motorola (they also designed it).

As for troubleshooting, make sure that the SES light does the blink off. If it doesn't then don't try to start the engine, the ECM is in limp mode and the back up fueling is for 28#/hr injectors. Not the larger ones that are installed, may need to replace the spark plugs from running it in limp mode.

SES blink: at key-on, engine-off, the SES light should turn on briefly, blink off, then stay on solid. Can repeat the test after a minimum of 10 seconds of key-off.

Start off with the minimum, just the ECM and chip. Even a stock chip can be used. Look for the SES blink. Once you have that try the correct chip for your set up, if you get the SES blink then try to start the engine.

RemoveBeforeFlight

P.S. quick note on the SES (service engine soon), our cars it may be CEL (check engine light). I've never looked at it well enough to know what is reads :eek:
 

NOTSOFAST

Member
I get no ALDL Data, key on , ses lights up and appears to be frozen. I get no code 12 if I ground the ALDL. I have checked black/white wire for a break , and nothing. I also have looked for damaged black/tan wire to ecm ground, and nothing. The few times the GN started, it felt like I was running on 2 cylinders. If I gave it gas , it struggled to stay on. I have spark and fuel , according to trouble shooting coil pack. Fuel pressure at 43lbs on fuel gauge. Since code 42 was last code it threw, I have trouble shot for that. Could esc be bad? By luck, could I have gotten a bad ecm , as even when I changed chip still no change when trying to start. Pulled wires out of loom, and didn't see any damaged wires. So at this point I'm stumped.

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NOTSOFAST

Member
Had to change plugs, as I forgot to disconnect inj harness. Test light , lights up when touching inj plugs. Don't understand if I have re-set ecm, aldl should blink when key on engine off. But ses stays lite. Even my SM doesn't show any parameters, it lights up , then no lights. So I can't even pull any codes if ecm has some stored. Have an other ecm ordered and will try it. But at this point, 1-3-5 do have spark. So it has to be a damn gremlin.

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RmvBfrFlght

Well-Known Member
With the SES lit up solid the ECM is in limp mode. The back up fueling will allow the engine to run, but very rich. And there won't be any spark advance.

My guess is that either the chip or the ECM is bad. Look for the SES blink and don't start the engine until it does blink.

And once the SES blinks the SM will work and you can blink out any codes. Hopefully there won't be any (need to run engine to get any codes set).

{added} The ESC module isn't the cause of this issue.

Here is another test that can be done: remove the (large) chip from the ECM and do a key-on, engine-off. The SES light should flicker rapidly, if it does the ECM is likely OK. If it's just solid on or solid off, the ECM is toast. {/added}

RemoveBeforeFlight
 

NOTSOFAST

Member
ok, I pulled the chip and with key on engine off, SES light is on and does not blink. So this indicates ecm is bad? What about the code42 it threw? If I unplugged the orange wire it should have erased all codes, correct.
 

NOTSOFAST

Member
ok, installed new ecm and SES light blinks when prom is missing. Installed original prom and GN fired right up, but wife wouldn't let me keep it at idle to clear all the combustion cylinders as fuel got really thick in garage. But I did notice ses stayed on, with?
 

NOTSOFAST

Member
how long should SES light stay on with new ecm? since new ecm is installed, GN shouldn't have any codes or is there a possibilty that i may still get code 42 or any other code for that matter? how long does it take for ecm to re-learn after being installed? I hate having to go to work , when I could be home getting GN sorted out. :D I did install original chip back in, if chip is bad , that would cause SES light to stay on again. I will swap out with another TT chip and see if SES light turns off.
 
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RmvBfrFlght

Well-Known Member
ok, I pulled the chip and with key on engine off, SES light is on and does not blink. So this indicates ecm is bad? What about the code42 it threw? If I unplugged the orange wire it should have erased all codes, correct.
Yes, that ECM is bad. Don't worry about any codes at this point. Just need to get the engine running on the proper chip.


ok, installed new ecm and SES light blinks when prom is missing. Installed original prom and GN fired right up, but wife wouldn't let me keep it at idle to clear all the combustion cylinders as fuel got really thick in garage. But I did notice ses stayed on, with?
The blinking SES with no chip is a good sign. The ECM is actually running.

The real question is: did the SES do the blink off with the original PROM installed? If not then the PROM/chip is bad. If it did the SES blink that is a good sign as it means that the ECM is running from the chip.

how long should SES light stay on with new ecm? since new ecm is installed, GN shouldn't have any codes or is there a possibilty that i may still get code 42 or any other code for that matter? how long does it take for ecm to re-learn after being installed? I hate having to go to work , when I could be home getting GN sorted out. :D I did install original chip back in, if chip is bad , that would cause SES light to stay on again. I will swap out with another TT chip and see if SES light turns off.
There won't be any codes in the new ECM until the engine is running from the ECM & chip. There isn't much to relearn, it happens quickly.

If the original chip is bad you won't get the SES blink at key-on, engine-off. So look for that.

If it does do the SES blink and the SES remains on with the engine running, then there is most likely a sensor fault. Can get the code via the ALDL blink out or via the SM.

I want to reiterate, do not run the engine until the SES does the blink off at key-on, engine-off. Can repeat that test after ten seconds of key off. The reason to not run the engine until the SES blinks, is that the back up fueling will deliver nearly twice the correct volume of fuel. That is going to have a detrimental affect on the engine.:eek:

RemoveBeforeFlight
 
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