Newbie w. New GN

[Steve Wood]

ses out?  You gotta another ecm to try?

[bryes]

I moved the car again an

d the light was off.  I'll try swapping back to the old ecm to Ser what happens.

[bryes]

I started car up a couple more times and no ses. Then I swapped in the following sequence. starting the car up to see if the see illuminates.

old      on
new.   On, restarted off
old.    On
new.   Off
old.    on
new.  off

Don't know what it all means but I'm working my way up to guru level at swapping ecms and ignition modules alike 

[Steve Wood]

Sounds like the new one is bad

[bryes]

That is the third one to go bad in the last 500 miles. Any ideas what causes this?

[Steve Wood]

same brand rebuilds or used ones?

[bryes]

Different brand rebuilds

[Steve Wood]

I might take the ecm voltage chart and see if anything is out of whack plus do a voltage drop check between the ecm case and the negative battery terminal with the engine running

[Steve Wood]

also, check the wiring harness where it comes thru the firewall under the hood, just behind the driver's side valve cover.  make sure it is not laying down the back end of the valve cover (or just behind the cover)in the area where the harness forks.  There is a screw that emerges thru the firewall into the under hood area.  I think it holds the gas pedal bracket in place.  If the harness sags down and lays on the screw, it can cause a lot of different problems as it rubs into the wires.

Normally, the harness is held up by a stand off that goes over the rear valve cover stud.  But it often breaks with age and allows the harness tor rub back and forth on the screw.  the screw is not readily apparent unless you feel under the harness for it.

[bryes]

Ok ill try what you suggest when I get a chance. It might be a couple of weeks unfortunately, I'm working out of state for awhile.

[bryes]

Sorry for dropping the ball on this for almost a year. I've been working out of state and have been focused more on painting my uncles Malibu as posted in the "bodywork" section. I intend to get to this soon, I'm back in Ohio the next two weekends so we'll see what happens then.

[Steve Wood]

Lol

[bryes]

Sorry for not posting sooner, but life kind of got in the way for the last couple of years. I was able to fix the problem and the car has been pretty much trouble free for the last year, so I am confident that the issues discussed previously have been solved. I think the car had 2 problems simultaneously, so that is why it was so maddening.


   Problem #1, the "A" connector on my ignition module terminal was probably making intermittent/poor contact.


To fix the problem, I was able to slide the metal end on the wiring harness side "A" terminal out and bend it so it made better contact. There's a picture in this thread about 10 posts back that clearly shows what I'm talking about. After that, no code 42 SES light ever again and no more failing computers.


After problem #1 was fixed, I still had an intermittent issue where the ignition would cut out every so often. Sometimes it was when I hit a bump in the road, more often then not it was at WOT or close but less frequently it seemed random....It felt like someone just turned off the key for a split second. Then it would cut back on after a split second, often backfiring. I blew out my muffler one time this way. The SES light would come on for a split second, but there would be no code. This went on for a year or so, often it seemed to come and go. Because I had just bent the connector to "fix" the issue, I thought it might still be "Problem #1".So I eventually soldered in a new Casper's Ign. module connector from. Not long after that my car died in the driveway (no-start), which is when I found the real culprit.


   Problem #2, the ignition module.
My first inclination was that my solder job was to blame, but it wasn't. I remember next going through the "no-start" tree and coming up with a bad ign module as a possibility. Even though I had already replaced this part, I bought a new AC/Delco (the previous was a "standard" part I think) unit and I've had no issues since.

[Steve Wood]

After all the work you put into it, you gotta be one of the foremost troubleshooter s around!  I'm glad you came back and told us what you found.  I bet it was nice to drive it fora a change

[bryes]

Well without this site I wouldn't even know where to start other than swapping out parts.  Thanks for that!


Yes, driving it is nice. It's just about like a normal car now, runs close to how I'd imagine they should when most everything is right at least.  I don't put many miles on it, but I do daily drive it frequently when the weather is cooperative. It's a fun car and real car people appreciate it I think.