GM electronics

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  #1  
Old 01-25-08, 07:44 PM
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GM electronics

I have a 2000 LeSabre. For several years now, the message center that displays the odometer, and other messages has had a condition in which the connection between the computer and the display seems to have become susceptible to shorting by the humidity in the ambient air. After the A/C has run for a while and removed humidity the problem ends and the display again works, ungarbled. In sub-freezing weather with no moisture, the display seems to work, until it warms, and if long enough for moisture to evaporate, works again. This has been an annoyance, but didn't affect the operation of the car.
Recently, the disrupted connection phenomenon seems to now have occured in a connection somewhere between the computer and the cylinders, such that the engine misses during times of moisture. Again, during sub-freezing temperatures the engine runs fine without missing, and as the heat from the engine warms the car, the occasional missing recurs, often causing the check engine light to turn on. In severe occurences the light blinks.
The GM dealer wants to simply replace plugs, wires, and coil, which I am confident will accomplish nothing more than drain my bank account.
Where can I find the resource to track the problem down in the computer controls and connections to fix it, or someone who can do it for me?
Thanks.
 
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  #2  
Old 01-26-08, 11:00 AM
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It probably does need plugs and wires. If you want to try and diagnose it yourself, you will need a scan tool that will monitor engine miss data. If your vehicle still has the original plugs and wires, and is close to or over 100,000 miles, it's time for a tune up.
 
  #3  
Old 01-26-08, 11:12 AM
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First thing that pops to mind is did you buy this car used because it sounds like a FLOOD car.

But with that being said if you decide to replace the plugs and wires be SURE to use the GM, OEM plugs and wires.
These engines are very sensitive to aftermarket ignition parts.
I speak from experience.
They're are only alittle more money but are more than worth it.
 
  #4  
Old 01-26-08, 01:17 PM
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Mackey is right on. With the aftermarket stuff, you're just asking for problems.
 
  #5  
Old 01-26-08, 01:38 PM
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OEM vs aftermarket

Hey mackey and Mr Dummas (did ya get that name from that commercial...lol)

Not even thinking of dis-agreeing here, but could you explain a bit more. Was always under the impression that premium parts were all good. I know the store brand cheapo's are to be avoided, but thought once you moved up to say...AC/delco, motocraft brand, etc...you were getting just as good or better than OEM from the dealer.

Or are you saying, "go with the same name brand from the parts store", NOT.... "buy from the dealer"?

In addition to just learning, reason I ask is, I've seen markup on parts from a dealer thats just crazy. Same brand, same part #...cost is 2,3 times same thing at parts store.

Thanks guys
 
  #6  
Old 01-26-08, 03:06 PM
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When it comes to ignition componants on GM vehicles, I highly recommend going with OEM parts. As a technician at a GM dealer, I have seen hundreds of cars come in the shop with misfire issues due to aftermarket plugs and/or wires. They are not very good in quality. If you can find AC Delco plugs and wires elsewhere, other than the dealer, for less cost, then by all means snap them up. Either way, as long as they are AC Delco parts, you'll be good to go.


Oh, and the name, it's my real name.............


































just kidding, LOL.
 
  #7  
Old 01-26-08, 03:08 PM
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parts

Ok mr D
thats what i was thinking you meant. Thanks!
(not that I have a GM presently, but may be in my future, they seem cheaper here than Ford...and don't get me started on Dodge's!!!!)
 
  #8  
Old 01-26-08, 03:55 PM
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Originally Posted by Gunguy45 View Post
...and don't get me started on Dodge's!!!!)
Must not be like mine then that has 252,000 miles on it and runs like a top in -20 below and 100 outside, and steering is like-new tight, and has gauges, tach, and light bulbs can all be changed out in seconds, and you can easily access everything in the engine compartment. And is 600 pounds overloaded and still runs like a top.
 
  #9  
Old 01-26-08, 04:33 PM
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Ecman,
Just my personal opinion...I've had no luck with 'em. Course I violated the first rule.....never buy in the first model year (on the second one).

2 Dakotas....1st was a 95 v-6 , rotors at 14k, timing chain at 45k (starting to sound like a diesel at idle, rattle rattle )..........hmmmm I really like the looks of the new ones...soooo.....

2nd was 98,V-8...leaking heater core w/in 10k (warranty payed), bad paint (dealer payed), rotors 16k (I payed), cracked head bout 30k (warranty payed), bad catcon 45k (warranty payed), cracked head (again!!!never fixed) 55k, cracked heater core (I payed after 1 yr no heat), bad catcon 85-90k (EPA payed, how bout that!!!!), bad a/c compressor/coil 92k......sold it!!!!!

Like I said...I just got bad ones..neighbor had a 20y/o Dodge truck..vroom vroom every day. I love the looks of Dodge products, just don't think the engineering was up to par at that time.

Like the old saying "fool me once........."

What model do you have?
 
  #10  
Old 01-28-08, 06:46 PM
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There is no connection between the instrument cluster and the engine management computer that would cause a misfire. The instrument cluster simply displays information when the other modules (like the ECM or BCM) tell it to. On some cars it serves and anti-theft function, but that's not your problem.

You probably do need plugs (and wires if your car has them). The flashing SES light is probably letting you know that the ECM has detected a misfire.

Condensation in the instrument cluster doesn't necessarily mean that it's a flood car. Mud, on the other hand, is a pretty good indication.

Jim
 
  #11  
Old 01-28-08, 06:58 PM
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oooh....don't get me started on Dodges either........I finally got rid of my wife 01 Stratus......probably the worse car ever.


Jimmy, that Caddy seems to be missing some pieces....
 
  #12  
Old 01-29-08, 02:27 AM
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Caddy

Is the Caddy a Katrina case? What happenend to the thing?
 
  #13  
Old 01-29-08, 02:50 AM
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Originally Posted by michael van View Post
Is the Caddy a Katrina case? What happenend to the thing?
It's a victim of a flood caused by the remnants of one of the many hurricanes we had in 2004. The storm hit Aliquippa, PA and submerged a new car lot there. 200 cars were lost, mostly new and still wrapped in plastic. My uncle, who is in the salvage business, split the lot with another dealer. It was really eerie to look at them all. They had all been power washed (inside and out) before auction and you'd never know they were totals until you got close enough to see the mud on the insides of the instrument clusters.

It took me 3 months of nights and weekends to reconstruct that Cadillac using a collision-totaled carcass for electronic parts. The interior is still original as are all the mechanical parts. I dismantled it and cleaned every nook and cranny with various scrub brushes (some as small as a toothbrush). I've been driving it since March of 2005 without any trouble:

http://www.turbojimmy.com/dts/dts.html

Jim
 
  #14  
Old 01-29-08, 04:23 PM
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looks good

The Caddy looks good I really liked looking at your link on the caddy as it was taken apart.
It looks like a lot of work tearing out that dash to replace all the electronics. But in the end the thing looks brand new.
 
  #15  
Old 01-29-08, 05:05 PM
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Originally Posted by michael van View Post
The Caddy looks good I really liked looking at your link on the caddy as it was taken apart.
It looks like a lot of work tearing out that dash to replace all the electronics. But in the end the thing looks brand new.
Thanks. It was no fun while I was doing it but it worked out in the end. I buy a lot of totals from the guy but this was my first flood. I had the dash in and out of it a few times until I realized that the wiring harness from the collision-total was one model year off and thus totally different than mine. I put the original harness back in and I was good to go (though it set me back many, many hours).

It's been a great running and very comfortable car. The DTS trim level has lots of neat features you don't get on the 'regular' Deville. I hadn't owned a Cadillac up until this point but I think my next car will definitely be another Caddy.

Jim
 
  #16  
Old 01-30-08, 06:18 PM
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GM electronics

Whew!
Thanks guys for all your insight.
To respond to a couple of points, I bought the car used with 36k on it, it now has 132k.
If the ignition hadn't worked right for up to about 131k, one would wonder about a flood car, but in this case it was owned by someone nearby who traded in on a new model after 3 years.

I expect that no connection exists between the dashboard electronic computer and the engine compartment electronic computer. My theory is that aging embrittled insulation or connector or something similar first noticed in the passenger compartment dashboard displays 30k miles ago is now occuring also on the wiring or connections in the electronics that run the engine. Remember, that the problem only occurs when there seems to be moisture/humidity present. After warming up to dry out, the 3800 V6 engine still runs like a top again.

Does a Chilton's manual give sufficient information to trace down and inspect the electronics? Can I even get at them without taking the car apart for weeks? If it's more than I want to tackle myself, where would I find a real mechanic who can track down and repair a problem instead of a robot GM dealer technician who is not capable of doing anything more than removing and replacing parts, (on my dollar) but couldn't track down, figure out, and fix a problem if his life depended on it?

And although the problem only developed a thousand or so miles ago, replacement of the plugs, wires, and coil probably are in order at this mileage.

Whaddya think?
 
  #17  
Old 01-30-08, 06:35 PM
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Originally Posted by Diamond Star View Post
I expect that no connection exists between the dashboard electronic computer and the engine compartment electronic computer. My theory is that aging embrittled insulation or connector or something similar first noticed in the passenger compartment dashboard displays 30k miles ago is now occuring also on the wiring or connections in the electronics that run the engine. Remember, that the problem only occurs when there seems to be moisture/humidity present. After warming up to dry out, the 3800 V6 engine still runs like a top again.

Does a Chilton's manual give sufficient information to trace down and inspect the electronics? Can I even get at them without taking the car apart for weeks? If it's more than I want to tackle myself, where would if find a real mechanic who can track down and repair a problem instead of a robot GM dealer technician who is not capable of doing anything more than removing and replacing parts, (on my dollar) but couldn't track down and fix a problem if his life depended on it?

And although the problem only developed a thousand or so miles ago, replacement of the plugs, wires, and coil probably are in order at this mileage.

Whaddya think?
I think your misfire is more related to a failure of a common ignition component (like plugs or wires) than a breakdown in electronic wiring. Despite all of the electronic controls, the engine still relies on high-voltage coils connected to spark plugs to ignite an air/fuel mixture just like they did when the idea of an internal combustion engine was new.

There is a connection between the instrument panel and the Engine Control Module (ECM) but it's sort of a casual relationship. The instrument panel collects information but does not act upon it in a manner that would cause the ECM to change its behavior. There is nothing in the connection between the ECM and the IP that would cause a misfire.

I still think that your IP issue and your misfire are totally unrelated and do not indicate a deterioration of the wiring in your car.

Chilton's manuals are all but useless. An www.alldatadiy.com subscription costs about as much as a Chilton's manual and contains WAAAAY more information - including wiring diagrams.

Jim
 
  #18  
Old 01-30-08, 07:40 PM
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Well, not all dealer mechanics are GM robots. There are about 2 of them at every dealer though. If you were in Michigan, I know a Buick dealer that would hook you up .
 
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