1988 Cad DeVille

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  #1  
Old 02-05-02, 06:21 AM
zed101
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Question 1988 Cad DeVille

I have a 1988 Cad DeVille with the 4.5 FWD. A mechanic replaced several of the sensors about two month ago. Recently, I took the car for a diagnostic test, but the tech said that my computer was in 'limp' and would not read. In addition, he gave me some minor pointers like changing my wires. After changing the wires, the skip left, but the vehicle would not accelerate above 50mph and shut off while coasting. Next, I changed the spark plugs. Now, the car will idle, but when I put it in gear there is no acceleration ( I can't even leave my driveway) . If I press the gas to the floor, the engine will not rev. It sounds as if it is bogging down. Some black smoke was coming out of the tailpipe and passed my hand across it. For the breif second that my hand passed, the exhaust was hot enough to burn my hand. I need help! Are there any ideas of what my problem is?
 
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  #2  
Old 02-05-02, 09:17 AM
Joe_F
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Black smoke is indicative of it running rich and dumping fuel.

Fuel pressure? Check it with a gauge.

Run a code check of any trouble codes and let us know what you find.
 
  #3  
Old 02-05-02, 11:14 AM
zed101
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Question Gauge and Codes

Hate to be a burden, but my computer is in limp. How can I get the codes? I'll also need basic instructions about checking the fuel with (what type of gauge?). Thank you!
 
  #4  
Old 02-05-02, 12:24 PM
Joe_F
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Fuel pressure gauge, which Autozone for one, can rent you for free.

As for the computer in limp method, go to my signature file or www.batauto.com and see if you can pull your codes.

Disconnect the battery and try to see if that resets the computer or not.
 
  #5  
Old 02-06-02, 07:12 AM
zed101
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Unhappy Help

I pulled the codes off the internet. Thank you! After following the instructions, I watched for the flashes. The flashes were so fast and frequent that I got confused. They appeared to be in intervals of four (4). If they simply repeat the same code then I would guess the forty-four (44) is my number. According to the GM codes, the Oxygen Sensor is where the problem is. Could that be right? Or, am I misinterpreting the flashes?
 
  #6  
Old 02-06-02, 09:06 AM
xiii13
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Was the O2 sensor ever changed? If not that sensor has been in there 14 years - replace it anyway. Should be replaced at least once a year.
 
  #7  
Old 02-06-02, 09:11 AM
zed101
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Smile 1988 Cad DeVille

I forgot to ask. Any idea where the O2 sensor is located?
 
  #8  
Old 02-06-02, 09:18 AM
Joe_F
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In your exhaust manifold. Looks like a spark plug with a wire coming out of it.
 
  #9  
Old 02-07-02, 12:13 PM
zed101
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Smile Almost Done

Okay, I dropped the exhaust system to replace the converter and O2 sensor. I having problems putting the new sensor in, I can't seperate the converter and tailpipe, and the airflow tube is full of gunk. Do I need to take the exhaust system to a muffler shop and have them seperate and replace the new converter? Do I need to replace the air flow tube or simply clean it out and replace the valve that is attached to it? Oh, I have not forgotten the fuel pressure gauge. I just have gotten that far yet! Thank you for your assistance!
 
  #10  
Old 02-07-02, 03:56 PM
Joe_F
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Whoa Nelley.

The O2 sensor just screws in and out (special tool you get at the parts store).

No need to drop the exhaust! Get a repair manual for this car before going on and read up. Try the link in my signature file.
 
  #11  
Old 02-08-02, 11:49 AM
zed101
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Wink Let Me Back Up!

I found that the converter and the air pump/exhaust check valve was stopped up. There for I had to replace themand the O2 sensor. Now I'm back to square one. I believe that the new spark plugs have fouled out ( I pulled the No. 8 out and it was covered with smut); however, I don't have the problem of bogging down anymore. The vehicle shuts down as if it is idling too low or not getting fuel. I'll get the fuel pressure gauge for that test!
 
  #12  
Old 02-08-02, 02:49 PM
mooser1
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as per Joe's advice you should still check your fuel pressure just in case.....the same "smut" fouling your plugs has probably also fouled the IAC, idle air control valve on the throttle body....this valve can be cleaned and reset, refer to a manual for the proceedure....if you stick in a new set of plugs and then drive the heck out of it for a few minutes, she'll probably clean right up......I mean DRIVE it, don't just lope around town, take it out on the open road and make it work......you'd be surprised how opening an engine up once in a while will keep some of these emissions related valves and sensors operating as they should....around town, stop and go, idle all day driving is the worst thing for any gasoline engine, whether carb'd or injected, allows carbon "smut" to build up every where.....
 
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