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My free Eldorado UPDATE!!


dkedrowitsch

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Today I changed the spark plugs to the correct AC Delco Platinum plugs and the car started right up and ran smooth! After letting it warm up and restarting it a few times to make sure everything was OK, I pulled it into the shop and did some general maintenance. Oil change, cleaned the EGR tubes, sprayed and cleaned the throttle body, set the timing, added Bars Leak (car has new radiator and fresh fluid so I just dumped the Bars Leak in) and gave the car a good look over. I noticed the tach and speedo were not working when I pulled it into the shop. After setting the timing the tach worked when I took it out of "set timing mode" but I never checked the speedo again. You'll see why in a second.

After I let it idle for about 45 minutes I shut it off for a bit and when I restarted it, it went RIGHT back to it's original problem of idle hunting, setting all kinds of funky codes, and eventually stalling. It also got stuck in the set-timing mode again, started complaining about over heating, and all the stuff it did before. I tried to add additional grounds to the engine and body of the car using a set of jumper but nothing would help. The only thing that cures it is to let it sit and cool off and it runs fine again until it gets good and warm. I hooked up the Snap-on scanner and was watching what would happen right as the car would act up, and as soon as everything goes haywire, the coolant sensor jumps from like 200F to 280F, the MAP jumps from like 1.02V to 5V and the TPS starts jumping all over the place. I can't imagine a ground doing that, especially because all those sensors don't even use the engine ground.

So, i think I have a bad PCM. Autozone has them for 87.99 with a $100 core so unless anyone has some other ides, I'll give that a try.

Can enyone tell me where the engine and harness grounds under the hood are? I'd like to check these before throwing a new computer at the car.

Thanks!

Dieter

BTW: I noticed the car doesn't have dual exhaust. Do all 92 Eldorado's have the hangers for a dual exhaust system if I decide to change it after the car is back on the road?

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Dieter,

As far as I understand you think the PCM is acting up when the motor gets hot. Hmmm... may happen because the PCM is in close proximity from the heater core.

You can easily bypass the heater core to eliminate that possibility.

Here you can find some directions to bypass the heater core. i had to do it on my way to Washington, DC from PA when the heater core started leaking.

http://caddyinfo.ipbhost.com/index.php?how...ing+heater+core

The saddest thing in life is wasted talent

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Well I didn't think of it that way but it might be something to try. :) The PCM itself will get warm or even hot just because of all the electronics packed in it. Plus it has to drive 8 high impedance injectors and a throttle control motor. All of that adds up to a pretty good amount of current. Usually borderline electronics will act up when they are warm.

I really can not think of anything else that would cause so many wide spread problems except for the computer itself to be bad.

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adallac,

Doesn't the PCM itself heat up? That's why it was moved under the intake box so intake air would be drawn over it and cool it. That would lead me to believe it gets pretty warm on it's own.

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adallac,

Doesn't the PCM itself heat up? That's why it was moved under the intake box so intake air would be drawn over it and cool it. That would lead me to believe it gets pretty warm on it's own.

Ranger,

As far as I remember in my car the PCM, BCM and the programmer were OUT of airflow. Everything is pretty packed under the glove box. Even removing the glove box and leaving the lead open may contribute in cooling the computers.

Of course the PCM warms up on its own, but heat from the heater core when the coolant is around 230 might be that straw. Just my $.02. I would try before try if it changes the situation - the PCM is the culprit.

The saddest thing in life is wasted talent

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Well I didn't think of it that way but it might be something to try. :)  The PCM itself will get warm or even hot just because of all the electronics packed in it.  Plus it has to drive 8 high impedance injectors and a throttle control motor.  All of that adds up to a pretty good amount of current.  Usually borderline electronics will act up when they are warm.

I really can not think of anything else that would cause so many wide spread problems except for the computer itself to be bad.

Is there any way you can wrap or pack the PCM heatsink with ice as a test? Maybe a freezer ziplock bag or something like that? If you can eliminate your symptoms by forcing the PCM heatsink temp. down, you have your answer.

Another thought is other engine sensors that send valid data at lower engine temps. but are delivering bad or confusing data on a hot start. Such as inlet air temp. or air density, or coolant temp., or whatever inputs your PCM is looking at??

Jim

Drive your car.

Use your cell phone.

CHOOSE ONE !

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I could cool it easily with ice in a bag, yes. But back before the plugs got fouled out, it would freak out and stall after running only two or three minutes. I doubt that's long enough for the PCM to get hot enough for component failure. I know the PCM in my truck takes an hour or so before it starts to get pretty warm to the touch.

Also, it's not just a hot start problem. I can start it and it'll run smooth and then start acting up.

This is very strange indeed. :) I guess that's what you get with a free car! LOL

So does anyone know where the engine harness grounds are?

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Today I changed the spark plugs to the correct AC Delco Platinum plugs and the car started right up and ran smooth!  After letting it warm up and restarting it a few times to make sure everything was OK, I pulled it into the shop and did some general maintenance.  Oil change, cleaned the EGR tubes, sprayed and cleaned the throttle body, set the timing, added Bars Leak (car has new radiator and fresh fluid so I just dumped the Bars Leak in) and gave the car a good look over.   I noticed the tach and speedo were not working when I pulled it into the shop.  After setting the timing the tach worked when I took it out of "set timing mode" but I never checked the speedo again.  You'll see why in a second.

After I let it idle for about 45 minutes I shut it off for a bit and when I restarted it, it went RIGHT back to it's original problem of idle hunting, setting all kinds of funky codes, and eventually stalling.  It also got stuck in the set-timing mode again, started complaining about over heating, and all the stuff it did before.  I tried to add additional grounds to the engine and body of the car using a set of jumper but nothing would help.  The only thing that cures it is to let it sit and cool off and it runs fine again until it gets good and warm.  I hooked up the Snap-on scanner and was watching what would happen right as the car would act up, and as soon as everything goes haywire, the coolant sensor jumps from like 200F to 280F, the MAP jumps from like 1.02V to 5V and the TPS starts jumping all over the place.  I can't imagine a ground doing that, especially because all those sensors don't even use the engine ground.

So, i think I have a bad PCM.  Autozone has them for 87.99 with a $100 core so unless anyone has some other ides, I'll give that a try.

Can enyone tell me where the engine and harness grounds under the hood are?  I'd like to check these before throwing a new computer at the car.

Thanks!

Dieter

BTW:  I noticed the car doesn't have dual exhaust.  Do all 92 Eldorado's have the hangers for a dual exhaust system if I decide to change it after the car is back on the road?

Ok, think about this, did you pull the ignition module out of the distributor? If I am not mistaken when it is installed there is a heat transfer paste that goes on behind it to transfer heat away from the module, sort of like a computer processor does. It could be overheating or it could have been damaged by disturbing the contact between the module and the dist....and overheats, check that coolant sensor also, Mike

Early on sailors navigated by the stars at night and the North star became the symbol for finding ones way home. Once you know where the Northstar is you can point your ship in the right direction to get home. So the star became a symbol for finding ones way home or more symbolically even finding ones path in life.

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Nice schematic, Dieter

Early on sailors navigated by the stars at night and the North star became the symbol for finding ones way home. Once you know where the Northstar is you can point your ship in the right direction to get home. So the star became a symbol for finding ones way home or more symbolically even finding ones path in life.

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Mike: Actually I put a brand new ignition module in the car. And I put the heat shield back where it came from. I also used heatsink compound on the back of the module to make sure it has sufficient heat transfer into the distributor base. My no-spark issue seems to have been caused by badly fouled Autolite plugs. The GM AC Delco Platinums solved it, as well as a new cap, rotor, coil, and ignition module.

Now I'm stuck with figuring out why the sensor readings freak out when the car runs for a while and calm down after it sits. I still think I have a bad PCM but I will use the ground schematic stefank gave me to double check all the grounds.

Thanks for all the info all!!

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Well I tried, what about trying to cool the PCM with electrical component spray and see what happens, I think the PCM is under the dash on the passenger side.

Early on sailors navigated by the stars at night and the North star became the symbol for finding ones way home. Once you know where the Northstar is you can point your ship in the right direction to get home. So the star became a symbol for finding ones way home or more symbolically even finding ones path in life.

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Its a spray that is specifically used to cool down electrical components for troubleshooting I imagine you can get it at an electronics supply, I'd buy a few cans and chill the chicken feathers out of it.. before I replaced it, its the symptoms disappear (and hopefully they will with this method), then replace the PCM

Early on sailors navigated by the stars at night and the North star became the symbol for finding ones way home. Once you know where the Northstar is you can point your ship in the right direction to get home. So the star became a symbol for finding ones way home or more symbolically even finding ones path in life.

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On my '93 the PCM is behind the glove box under that plastic panel. You might want to access it and tap it smartly with your knuckles, observing any response, good or bad.

Another observation..

Have you carefully inspected all the battery connections and inspected the cables for any swelling which might indicate hidden corrosion under the insulation? These damned cars get "psychotic" when they don't get full voltage to the various components.

Just a W.A.G.

FWIW

YMMV

DFB

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Great news! Tonight I pulled the PCM and tried banging on it while the car was running and I could reproduce the problem EVERY time. It eventually got so bad the car would hardly run. So I set it in my toolbox ready to be replaced tomorrow.

I went back to tearing a Ford Winstar down for head gaskets and when I took a Pepsi break...what caught my attention in the corner of my eye?...could it be?...a PCM that looks EXACTLY like the one I just pulled laying in a pyle of left over "to be trashed" junk? I took a look and it was the same part number with a different MEMCAL installed!! I grabbed my MEMCAL and stuck it in and ran out to the car to try it. It runs PERFECT! Fired right up the first try, idled right down and as smooth as can be. Let it warm up and drive around the parking lot...no codes! Shut it off, start it up, bang on the PCM, jiggle wires....works perfect!

Hmm...I wonder what it was from? I'll ask the shop owner tomorrow but it seems to work fine in this car! What good luck after such a frustrating last week!

After a serious interior cleaning and putting the driver side door back together (needs a window regulator), I'll put it on the road. :)

Here is a pic I snapped just before dark. Don't worry the puddle under it is from another car. :)

P3140034_small.JPG

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What a coincidence! Glad you finally narrowed this down. I think PCM problems are the hardest to diagnose. You might want to open the PCM and look for problems with it, especially look for circuit board traces where the component has broken loose, but if you can use that one terrific. Mike

Early on sailors navigated by the stars at night and the North star became the symbol for finding ones way home. Once you know where the Northstar is you can point your ship in the right direction to get home. So the star became a symbol for finding ones way home or more symbolically even finding ones path in life.

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I took it apart already to look for obvious signs of broken solders but nothing sticks out at me. The boards are covered in the usual hot-glue coating so it makes it a bit harder to see. If I had to guess it would be a power or ground trace to one of the heat-sinked A/D converters because it affected the TPS, TEMP, MAP, and MAT at the same time when it would freak out. Maybe I'll just resolder every hole-thru solder with a dab of fresh rosin-core solder to clean up all the connections and stick it back in the car to see if it was that simple. I'm sure i can keep the PCM I found though, as it was in a trash pile to be thrown out next time we clean the shop. :)

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P3140034_small.JPG

SWEET eldorado.....what a find! If that was it's main problem, and you end up getting the PCM for free, than you got an awesome deal.

Great looking eldo! :D

-dave B)

P.S. try removing that front license plate holder and see what you think, IMO if gives the eldorado a MUCH cleaner look. I removed mine the first day I got mine. :P

Crystal Red Tintcoat Exterior | Shale/Brownstone Interior | 32k

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davedog: Thanks! It does look great from the outside, dosent it? It needs some serious cleaning inside though. The floor mats are muddy and it's covered in papers and junk. The seats are also kinda worn and with the leather being blue, the wear is very obvious. Maybe there is some leather dye/paint or something I can use to fix it?

It was a collage chick's car. Apparently she kept getting speeding tickets in it and almost lost her license. When it died, she gave it to the shop owner and now drives a Sundance. No speeding tickets in that! I know, I'm currently driving one too until my truck harness comes back. Or the Eldo is on the road. :)

I'm 99.9% sure the junk PCM is mine now. :)

Hey, you can kinda see the UGLY wheels in that pic! I'll have to pull it out and wash it so I can get some better pictures.

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Leather repair. :) The car has a blue interior that shows even minor leather wear very clearly. I'm looking around on the net and found a product that seems like it's right up my alley. It's called Magic Mender (http://www.leatherrepairkits.com) and they even have Cadillac colors.

Has anyone attempted this before? Any product reviews? To the best of my knowledge there are no rips, just the dye worn off on the front seats and cracked dye on the back seats.

Also, any ideas on what blue my car has? It should be Dark Sapphire Blue #8841 or Adriatic Blue #6680 but I can't tell. :) Apparently #6680 came out in 94, but my blue looks ligher then that I think. I have not paid close attention to the interior yet with all my electrical problems. Now that they are solved, I'd like to move on in my mini-restoration project. :)

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