hockeyhead019

Hey guys,

Car was dead when I got back from vacation but I jumped it no problem. While driving I noticed that the security light was blinking while driving. I carried on just thinking "hmm that's strange". Parked it and then when I wanted to get back in the car would turn over but not start.

I did some reading and found out this a feature of the security system which just doesn't fire the injectors. (FYI I checked the spark and the fuel system and both are fine) So I pulled the negative battery lead and was able to start the car just fine and drive home.

On the ride home I noticed the security light was flashing in sets of 3. Not sure what the issue is or why the security system is bugging out. I'm using the original keys to the car and don't believe I'm doing anything different from what I usually do driving the car.

Is there any other easy checks to do before I try and figure out if the ECU crapped out on me? I have another key to the car so I was planning on trying that tomorrow morning.

Cheers!

Cliff Harris

The first thing you need to do it tell us what year the car is. The SECURITY light functions were changed over time and the year affects what advice we give.

hcbph

It would help if you would check for any codes.

WVZR-1

Do you have the FSM for your '92? If yes do reads for CCM 8D section

Are you sure it wasn't SYS flashing 3 times? I don't believe I've ever seen mentioned a SECURITY flashing a particular sequence.

DO the CCM diagnostics that are pretty straight forward. If "BOTH" were flashing simultaneously it might hint to expect a CODE 54. Unless someone has actually experienced the same failure it's difficult to mention trials.

hockeyhead019

To clarify it's a 92 6spd. I'll check the codes tonight

@WVZR-1 Yes I'm sure it wasn't the sys flashing, it was the full word security on the bottom left side of the dash

JimLentz

Any other odd behaviors?

hockeyhead019

Jim, nothing abnormal while I'm driving. After I pull the negative battery lead and let it sit for a second she starts and runs fine.

What does the security system monitor? Key resistor in the ignition and the door switches correct? I'm trying to think of what else could be acting screwey besides the ecm. Maybe my steering column has something pinched? It does have the classic wobble from somebody using that to get it and out of the car.

hockeyhead019

UPDATE:

Drove the car into work today and noticed the blinking security light. Turns out the sys light was blinking in sync with it but I hadn't noticed before because I was destracted by the security light (oops) lol

After another 10 minutes or so the Service ASR light came on. Did some reading and it sounds like I may be suffering from a dying ECM. My question is why does this only occur once the car is warmed up? Could this just be an issue of the heatsink not having a good bond to the ecm anymore? Or is it more likely the internals are failing?

If I need to start looking for a reman'd ECM can anybody point me in the right direction? I'll be looking at zip and a couple other of the big ones but I wasn't sure if there was a better source for original ECMs

JimLentz

Sounds a lot like the cold solder problem with the ECM. The best/cheapest solution is to send the ECM to SIA Electronics or someone like them. It took me a little over a week to get the ECM back, but they are in the same state that I am in. I have not had any issues since I received my ECM back from them. When the ECM heats up the solder joints expand and can lose contact with the components on the circuit board.

hockeyhead019

Jim any idea what components of the board in particular are prone to this? $166 seems like a heavy fee to have somebody sit and re-solder components when I have a soldering iron at home lol

I was hoping it wasn't an issue with the ECM but all signs seem to point to it now

JimLentz

I am not sure what components they re-solder. I also have a soldering iron at home, was an electronic technician many years ago, but liked the idea of their lifetime warranty. They will test and replace any failing components as well. If you do send it in be as specific as you can about the issues you are seeing.

I even ended up buying a used ECM as a spare and another MEMCAL for my '92. The cold solder issue was not just a GM ECM issue, but I remember seeing it with HP JetDirect cards for their printers. I think it was related to going to solder with no or reduced lead content.

hockeyhead019

Thanks for the info Jim!

I'm going to pull out my FSM and go through some of the troubleshooting from this thread: https://www.corvetteforum.com/forums...cm-repair.html

I did have an almost completely dead battery recently so that may have had a role to play as well. Hopefully I remember to come back and update with the solution

Keith Huffstutler

Different cold solder issue. The HP JetDirect/Xbox RROD/NVIDIA stuff was because of brittleness induced by continuous heat cycles with Pb-free solder, 2005-ish. In 92, it was just regular solder, but it still can be affected by heat cycles, just not so quickly. You can see this with a lot of old monitors that are used for classic arcade games where the chassis develop cold solder problems over time. These can also cause the traces to lift away from the board, which would require jumper wires as replacements.

If you are comfortable with a soldering iron, you could re-flow the solder yourself in the ECM as a first step. If there are capacitors, you could replace those too, while you are there, since time likes to kill them. There are several videos on the subject on YouTube, especially with the aforementioned arcade monitor repairs. (Wow, I didn't expect that two of my hobbies would converge like this.)

Keith

WVZR-1

Without some confirmation I don't believe you can "rush to judgement" on the ECM. Have you spent any considerable time under the hood and have maybe had the ECM loose a time or two? A poor connection? Is the ECM original? If there's a label on the ECM it might be interesting to know what it says. If the ECM were original it would have the original "broadcast code" original build information as well as the "service required #. Has the PO maybe been into the same vicinity a time or two.

Until you do the codes and diagnostics involved I wouldn't rush to buy or arrange. Once codes are run and if maybe the ECM sees everything in circuits on a single connector maybe that would help. Much to consider particularly with an "intermittent".

hockeyhead019

No rush to buy anything here... just get a little too excited during posting lol I'm pulling codes tonight. For all I know it could have just been a battery low voltage issue after jumping it and not running long enough to charge fully.

Gotta grab my FSMs and sit down and cook through the codes.