That battery is shot. See if it is under warranty and get another one. If I leave the lights on my vette over night and then charge it with 10 amps for 15 minutes in the morning, it will start right up. My battery is 1.5 years old.

 

you will be kicking yourself if you find that all your problem was a bad battery to start with.
but I think it was more than that,but you never know

 

Yeah your telling me. Well it was completely dead and it took a charge a full charge and from what the statement read it is a good battery so well see. I'll be putting it back in soon. In the meantime while Im there Im cleaning up that ground and other posts for the positive to the main fuse box behind the battery. I didnt even know there was an additional main fuse box below with like 6 or 7 Big fuses for major circuts like the the fuel pump etc. Im scrubbing them all up and applying dialectic grease
Ultimately it was definitely more than a battery for sure and Im not to sure this will be the fix but I know I have a lot of bases covered and Im always getting closer ( I must be a an optimist lol )

 

Wow eventful day to say the least. So I put the battery in last night no start. I wake up this morning and figure to try again and wham starts up like majc, runs excellent. Then it stalls after like 10 minutes only this time it restarts and shuts off soon after and does this a couple of times before it wont start again for the rest of the day

so I see an oppertunity to pull codes and I get a 16 from the ecu. I then pull the ccm codes and get these three Modual 1 a H54 Modual 4 ( ECM I think ) H16 and a modual 9 H72

When trying to link my code scanner I get the message cannot communicate or something like that, Sometimes when trying to jump the a and b terminal I get a steady light and nothing not even a 1 2 flash and other times I get the codes flashing

I mean thinking about it having cleaned up the grounds by the battery not that they where corroded but also replacing the icm etc at least now the car is starting at times, not that this has anything to do with that

Right now I need to trace out these codes it seems to me like Im not getting communication from ecu to ccm at times and this si when it shuts off. I have heard of others getting their ecm fixed and this solved the problem. I think that is the next step but Im open to any ideas and would love to hear any thoughts on this from others who know about this stuff or who have had this problem. Not giving up I feel closer than ever and yet so far lol nevertheless Im gonna clean some more grounds next also byt eh starter and apply dialetric grease

Also I tried pulling and pushing the wire harness underneath the dash in various places while cranking to see if that would help close any open circuits etc but none of that worked, nor did I hear any electrical systems coming on or shutting off. I suppose this is kind of like a wiggle test while Im at it hoping that wiggling the wires will start the car. I checked the fuses none of them are blown, Hope someone can help me out with some thoughts or experience with what these codes mean. I know 16 is low opti resolution the other 2 I have no idea

Can the opti cause all of these problems or is the problem related to the ecm or between the ecm and ccm? wow I know speak a second launguage come to think of it lol Holy god you need patience for this Ill tell ya that

Mike

 

H72 --> Serial data line malfunction
So this history error code agrees with the problems you are having.

H16 - Low resolution pulse
This is worrisome. Did you get an AC Delco or MSD or what ? Have heard that some folks have problems with loose rotor screws on the rotor. FWIW, all the Optis I have replaced, I first opened them up, removed rotor screws and loctited them.

 

Got it running again. Hopefully it stays running. I scuffed up the opti harness connections not to sure if this is why but well see. Oh man please just stay running. Ive been all day at this

 

If it quits again, clear your error codes and then read them again. You need to see if your Opti keeps kicking off the engine with that H16 error code.


Here's how to clear your codes without disconnecting Bat. neg. term. :
To clear the codes,

1. With ignition "off" ground terminal #12 of the DLC (use bent paper clip to connect pin 4 to pin 12)

2. Turn ignition "on".

3. Press trip/odo button on the DIC until 1.7 appears in the trip
monitor area of the instrument cluster.

4. Press eng/met button on the DIC & hold until "---" appears in the
speedometer area of the cluster, this will clear CCM DTC'S.


To clear PCM/ECM codes do the following:


1. Press the trip reset button on the DIC until the desired system is displayed. In this case it will be 4.0.

2. Press trip/odo button on the DIC until the desired diagnostic mode(4.7) is displayed on the trip monitor area of the cluster.

3. Press & hold the eng/met button on the DIC until "---" is
displayed in the speedometer area of the cluster, this will clear PCM codes.


To clear ABS/ASR codes do the following:

Same as above but you’re looking for “9.7” on the trip odo


Does your '94 have a 12pin or 16pin DLC ?
Mine has the 16pin(system is still OBDI though)......hence short #4 and #12
if 12pin ........Short A&B

 

I think I figured it out boys yes al your right the code does agree with my symptoms. With that I have started the car 3 times in a row with shut downs etc. I am almost certain my original premise the ECU is the problem. While the car was running I pulled on the major grounds to the motor etc. I also pulled lightly on the harness wires to the ECU looking to see if I could get the car to stumble while doing this. Id say this is a good way to find out if connections are what is causing your problem. I mean even though I was so happy to hear it running and actually got it to operating temperature ( amazing feat in itself ) I had to do what came to mind next, I tapped on the suspect ECU and walla I got it to stumble. A few moments later I tapped on it again only with a little more zest and wham I got it to shut off. Right off the bat I knew this is my problem right here. Ill be sending this unit out unless someone has one theyd like to sell.

My guy at pep boys can send it to Borg Warner overnight and they will look at it and make repairs for a 127 bucks. Anyones thoughts on this or any other ideas as for getting one. I just lost an opt on ebay for a buy ot now on one but Im open to suggestions. The car ruuns excellent all the functions work the clutch is tight, reverse is good. I want so badly to take it down the block but no way. I live on myown and would not want to get stuck out there. I had a mother of a time getting this back into my spot when it would not start back up today. Also I believe cleaning those contacts at the opti harness helped a lot. I used a pointy little metal dagger with the tip bent slightly and scuffed the inner walls of the metal contacts. This is where the harness meets the opti. I was never a fan of cleaning contacts grounds etc but I am now lol and Im gonna do the same tomorrow with the ecu male connectors

Wow I almost certain this is the problem and I have isolated it. also when its running right there are no service lights on the dash at all. This should be made a sticky oneday lol. I worked my *** off to get this done. Imust have pulled all the fuses at least 3 times. I brushed up as many of them as I could and applied dialetric grease to all battery posts and grounds I could find. I must have traced a ton of wires for faults voltage continuity etc Ultimately I did not want to bring my car on a tow truck to the stealership

Keeping my fingers crossed lol

 

Al Borman
your the best. Thanks so much for following me on this post. I have relied heavily on your inputs and have always looked to see if you chimed in. Thank you so much. Read my above comments and tell me what you think

Mike

 

No problem Mike. I've enjoyed the ride(hah hah....so to speak) !! I agree with your assesment that your ECU needs serviceing or replacement. If you can stop the engine, or make it run poorly just by thumping the ECU housing, then this is definately not normal. Sounds like there is a loose wire inside, cold solder joint on one of the components, or perhaps a cracked PCB board.

Keep us posted !

-Al

 

Yeah you know what was puzzling and had me running for the optispark right away was the fact that he mentioned his symptoms started after he changed the coolant sensor. All the time I was looking around and see this indentation on the top of the ecu from one corner diagnally across the face pushed enough to seem like something was left on the ecu and the hood was closed leaving the impression and probably causing internal damage to the board

Of course this may not be the end of it or the problem but Im pretty sure as you mentioned that if I can knock the car off by tapping the ECU its a no brainer that something is up with that. Ill send it out with all of this info codes and symptoms and go from there unless I can get a good deal sooner on one. Ill definitely keep you posted. Hopefully it will all work out:

 

Sounds like you're headed down the right repair road now. To the victor belongs the spoils! Good job and keep us posted. Persistence overcomes resistance.

 

Mike, I've been following this all along and my hats of to you, for your patience and persistence in this tough diagnostic! Great job and keep us informed as to the outcome! Inquiring minds want to know and it does add to the valuable information here!

 

Yeah it sure does thank you. Ill keep you posted

 

Yeah this sure was a tough diagnostic and it can get ugly. Im well aware of the amount of wiring and sensors in this car now and it is scary but If I keep all contacts clean and maintain it I should be good. Well Im wrapping up the ecu as we speak and sending it to borg warner. I could have gotton a remanufactured cardone but I feel like keeping my original ecu and having them test it etc. Im gonna send a letter with all of the codes I got and the symptoms. I should have it back in a few days. Keeping fingers crossed. In the meantime Ill check all the harness wires for breaks and clean the contacts. Thank you for the compliment and support ttys

 

Mike, do you think yours is one of those cases where the Opti was blamed for something not it's fault?

Jake

 

yeah exactly. I mean everything you here with this car and many LT1s is the Opti but looking it over and going through the troubleshooting its not hard to see that there can be a multitude of reasons why there is no spark or loss of spark and this is probably going to be one of them. The ECU has been shipped off so well see what they say. Im almost certain its the ECU and even though one of the codes is a H16 History and it appears to be the opti it is obvious that if the ECU is broken in anyway board solder resister etc the ECU will have trouble sensing that low resolution signal or losing contact with it thus by making it the problem with the ECUs ability to pick up the signal. In short a code 16 in my option doesnt always mean the signal isnt being sent it could very well be the ecu having trouble picking up the signal because of damage to it and then it reports the problem when all along it is the problem so to speak lol Time will tell. I should have it back within a day or two, probably two lol. Can't wait I just want to be able to take it out for a run. When it is running it feels excellent but I couldnt go anywhere cause I knew it would just shut off damn lol TTYS and thanks for all the help so far

Mike

 

Mike, are you planning on taking any additional measures to shock-mount the stock ECM mounting bracket?

Do you think excess noise, vibration, and harshness (NVH) might have contributed to its demise?

 

[QUOTE=onedef92;1575117206]Mike, are you planning on taking any additional measures to shock-mount the stock ECM mounting bracket?

Do you think excess noise, vibration, and harshness (NVH) might have contributed to its demise?
Nice Motor lol ZR1 Better keep that baby tip top lol With that no I dont think there is a need to provide further shock resistance. The plastic tray is pretty flexible although with colder ambient temps that would change. So I might add a rubber grommet or two. Heat probably effects them but so far they seem pretty sturdy. Id say the biggest issue is not to put anything on top of the ECU and then shut the hood and definitely don't punch it as I suspect this fellow who owned it previously did out of frustration ( he was pissed when I came to get the car thats for sure ) He either closed the hood on it with something on top or punched it, there was a definite dent and the Board and its accompanying circuits are not even a half an inch within touching the top of the case. So with that Id say if anything, dont just slam your hood. Id close it nice and gently. Letting it down nicely and then just pressing the corners lightly to close each one. I will not let my hood drop closed no way, that I definitely would not trust lol

Mike

 

You know, you would think that the engineers at GM would have taken into account and tested for the effects of shock and vibration when the LT engine was being designed. I'm thinking it must have been in the testing stage in 1990 or so.

I don't know for sure but it seems logical for them to have tested for the effects of dropping the hood, etc. since that's what GM recommends as the way to close it.

However, since it's been mentioned it makes good common sense to minimize or eliminate as much shock to the PCM as can be. So NOT dropping the hood, to me, is the best plan out of the two options.

I hadn't even thought about this before, but am glad it was brought up. I know which way I'll begin using to close my hood from now on.

Thanks for that.

Jake