'91 Brougham 5.7 - 153k mi - just bought - black smoke/smog - HELP! - Page 2
Cadillac
 

Cadillac Forums | Help Us Help You | Advertise | Cadillac Parts | Cadillac News | Cadillac Classifieds / (Old System)

Cadillac Technical Archive | Cadillac Dealers | Cadillac Reviews | Cadillac Dealer Reviews | Cadillac Vendors

CadillacForums.com is the premier Cadillac Forum on the internet. Registered Users do not see the above ads.
+ Reply to Thread
Page 2 of 2 FirstFirst 1 2
Results 16 to 23 of 23
5.0 and 5.7 Discussion, '91 Brougham 5.7 - 153k mi - just bought - black smoke/smog - HELP! in Cadillac Engine Technical Discussion; You can replace the rotor and cap yourself! Don't waste your money taking it to a shop!...
  1. #16
    terrible one's Avatar
    terrible one is offline Banned
    Automobile(s): 1976 Eldorado project
    Join Date
    May 2005
    Location
    El Dorado, Arkansas
    Age
    24
    Posts
    1,631

    Re: '91 Brougham 5.7 - 153k mi - just bought - black smoke/smog - HELP!

    You can replace the rotor and cap yourself! Don't waste your money taking it to a shop!

  2. #17
    90Brougham350's Avatar
    90Brougham350 is offline Cadillac Owners Connoisseur
    Automobile(s): 94 FWB, 93 SDV, 94 FWB (sold), 90 Brougham (sold)
    Join Date
    Jan 2005
    Location
    River Falls, WI
    Age
    29
    Posts
    3,730

    Re: '91 Brougham 5.7 - 153k mi - just bought - black smoke/smog - HELP!

    Correct, the cap is very easy to replace. It's a 7/32nd socket. The rotor is even easier. The hesitation upon depressing the gas pedal sounds like a timing problem. Can you check your timing?

    Brian

  3. #18
    betterlife18 is offline Cadillac Owners Member
    Join Date
    Aug 2005
    Age
    30
    Posts
    21

    Re: '91 Brougham 5.7 - 153k mi - just bought - black smoke/smog - HELP!

    I have no clue how to check the timing, especially adjusting it. And I don't have a 7/32" socket to take the cap off. So tell me about the timing...

    And when I take off the cap, is the rotor just going to be sitting there? What is holding it in?

  4. #19
    90Brougham350's Avatar
    90Brougham350 is offline Cadillac Owners Connoisseur
    Automobile(s): 94 FWB, 93 SDV, 94 FWB (sold), 90 Brougham (sold)
    Join Date
    Jan 2005
    Location
    River Falls, WI
    Age
    29
    Posts
    3,730

    Re: '91 Brougham 5.7 - 153k mi - just bought - black smoke/smog - HELP!

    The ECM has a set-in-stone ignition spark curve. This means that if the base timing is off, the entire curve will be off. Naturally, the engine wants as much timing as the computer can give it without detonation, because this produces the most power. Having retarded timing can lead to hotter ignition.

    Timing is when the spark occurs while the piston is traveling upwards, compressing the air / fuel mixture. Idealy the spark happens BEFORE the piston reaches what's known as TDC, Top Dead Center. This when the piston reaches the top of the stroke, and begins the downward travel. However, since the air / fuel mixture takes a very short, but still existent amount of time to burn, the ideal time to ignite the mixture is while the piston is still traveling upwards, but not quite to TDC.

    When the spark ignites the mixture, the mixture does not explode as most people would think. Instead, it burns very quickly and creates enormous cylinder pressure which is the expanding gases from ignition. This burn is the very small amount of time you want to work with, to get the timing advanced. Advanced timing is when the spark occurs before TDC. Retarded timing is when the spark occurs after TDC. This is when the piston is traveling in the downstroke.

    Now, as you mash the fun-pedal, let's say, during passing someone or hitting the gas from a stop-sign, you're putting a lot more air and gas into each cylinder, trying to get more power from the engine. However, this extra air and fuel takes just a little longer to burn, therefore, the timing needs to be a little more advanced when you give the engine more fuel. Does this make sense? The computer uses the input from theCoolant Temperature Sensor, the Manifold Absolute Pressure Sensor, the Mass Airflow Sensor, and the Throttle Position Sensor to pick the exact timing from the curve it has.

    While the sensors it uses are unimportant, it is important to remember that the curve is set, so having the starting point off means the whole curve will be off. I hope this makes some sense.

    Therefore, if I were you, I would go to the store and pick up a small ratchet set or even just a 7/32nd socket and change the cap and rotor myself. Shop labor would be far more than the cost of doing this yourself. The rotor; just pull it up and out. You'll see that there is only one possible way for the new rotor to go back in. Same for the cap. It only fits in one way, and you'll know you've got it once you do.

    Once you do the cap and rotor, take it to a shop to check your timing. There is a single TAN with BLACK stripe wire infront of the heater core, right next to the oil dipstick. It comes out of the convoluted wire tubing that's a good inch wide, has most of the wiring for the engine inside it. This tan / black wire has a single connector. Shut the car off, and unplug it. Now have the mechanic check the timing. You want the BASE timing at 0 degrees. Unplugging the tan with black stripe wire puts the engine into base timing mode. Once you've set the timing to 0 degrees, shut the car off and re-connect the tan / black wire.

    The vehicle timing is now properly set! Good luck!

    Brian

  5. #20
    90Brougham350's Avatar
    90Brougham350 is offline Cadillac Owners Connoisseur
    Automobile(s): 94 FWB, 93 SDV, 94 FWB (sold), 90 Brougham (sold)
    Join Date
    Jan 2005
    Location
    River Falls, WI
    Age
    29
    Posts
    3,730

    Re: '91 Brougham 5.7 - 153k mi - just bought - black smoke/smog - HELP!

    Yes, I know 0 degrees doesn't sound like a good idea, but remember, once you re-connect the tan / black wire, the timing will jump back to ECM controlled, which will be something like 18 degrees BeforeTDC; BTDC.
    Just make sure the engine is at normal operating temperature!

    Brian

  6. #21
    betterlife18 is offline Cadillac Owners Member
    Join Date
    Aug 2005
    Age
    30
    Posts
    21

    Re: '91 Brougham 5.7 - 153k mi - just bought - black smoke/smog - HELP!

    BEHOLD, MY CADDY RUNS LIKE A CADDY AGAIN!

    You guys are going to freak out. Ok I went to Auto Zone and got me a MAP sensor cause a mechanic dude told me to. You are thinking that I'm prolly stupid for doing that. BUT! Yes, there's a BUT!

    The MAP sensor did not correct the issue. So I got fed up with spending money on guessing parts. I took it to an independant shop here in Nashville. Cost $70 for the labor, and ONE DOLLAR for the part. Could you guess what it is?

    It was the little hose that plugged into the bottom of the MAP sensor. THERE WAS A BIG FREAKIN HOLE IN IT THAT WAS JACKING THE COMPUTER UP. They swapped that sucker out and boooooy she's running good now! No SES light, no smoke, no hesitation, no rough idle, just sweet smooth Cadillac!

    CASE CLOSED.

    Next step: My A/C is leaking R12 about two cans a year (says the previous owner), not blowing cold. I'm getting it swapped over to Freeze 12 and live with the leak for now.

    Yay I'm so happy!

    Going out of town for the weekend, will be back Sunday night around 9PM Central time. Have a good weekend guys!

  7. #22
    90Brougham350's Avatar
    90Brougham350 is offline Cadillac Owners Connoisseur
    Automobile(s): 94 FWB, 93 SDV, 94 FWB (sold), 90 Brougham (sold)
    Join Date
    Jan 2005
    Location
    River Falls, WI
    Age
    29
    Posts
    3,730

    Re: '91 Brougham 5.7 - 153k mi - just bought - black smoke/smog - HELP!

    Quote Originally Posted by 90Brougham350
    Then, check all the vacuum hoses on the engine, a dried and cracked line somewhere can be a real mind boggler till it's found and replaced.

    Hahaha, Post #7! (shaking my head while laughing) Well, glad to see you got it all figured out. Nothing like a sweet running Caddy!

    Brian

  8. #23
    betterlife18 is offline Cadillac Owners Member
    Join Date
    Aug 2005
    Age
    30
    Posts
    21

    Re: '91 Brougham 5.7 - 153k mi - just bought - black smoke/smog - HELP!

    You were right. Unfortunately, I'm really stupid. I wouldn't know where to check for "hoses" and such unless they were snakes and jumped out at me. Especially under the map sensor behind the distributor and way back in the dark!

    I just got my A/C converted to Freeze 12. Cost me $230 .
    It's blowing really cold and makes my nipples turn hard enough to cut diamonds if I sit in there with it on long enough! A potentially bad thing is is that the compressor is making a racket. Gosh if that thing goes I'll be stranded .

    Oh well, I'm gonna stick a for sale sign on it with some rediculous price on it, prolly something like $3250. Hehehe, any takers?
    *Gone for the weekend*

Quick Reply Quick Reply

Register Now

Please enter the name by which you would like to log-in and be known on this site.
If you do not want to register, fill this field only and the name will be used as user name for your post.

Please enter a password for your user account. Note that passwords are case-sensitive.

Please enter a valid email address for yourself.

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Bookmarks

Cadillac Posting Rules

  • You may post new threads
  • You may post replies
  • You may not post attachments
  • You may not edit your posts
Read about Lincoln | Buick | Kia Forte Forum
Need products for your Cadillac? Check out your options at the links below:

custom floor mats | Cadillac Chrome and Black Chrome Wheels | window tinting