'91 Brougham 5.7 - 153k mi - just bought - black smoke/smog - HELP!
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5.0 and 5.7 Discussion, '91 Brougham 5.7 - 153k mi - just bought - black smoke/smog - HELP! in Cadillac Engine Technical Discussion; *My first post* Hello folks! I just bought a '91 Brougham RWD w/5.7 about two weeks ago for $1100. Steal, ...
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    betterlife18 is offline Cadillac Owners Member
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    Unhappy '91 Brougham 5.7 - 153k mi - just bought - black smoke/smog - HELP!

    *My first post*

    Hello folks! I just bought a '91 Brougham RWD w/5.7 about two weeks ago for $1100. Steal, eh?

    Symptoms
    *rough idling, running way too rich
    *thick, gritty black smoke/smog coming from exhaust, especially when I floor it
    *INTERMITTENT service engine soon light

    It had 152,000 miles, (almost 153 now since I have driven it about 700 miles sor far). Ever since I got it, it has had a thick, grity black smoke coming from the exhaust. Right off the bat my dad and I figured it just needs a major tune up, as it had been sitting in the lot for about two months without being cranked or anything. So first tank full I filled it up with Shell V-Power (25 gallons for that beast). Next tank I put in two tankfulls worth of Lucas fuel treatment (that stuff is the shizzy). I got some Bosch platinum plugs (not +2 or +4, just the regular ones) and a Borg wireset. Swapped them out, and after two tanks of V-Power and Lucas treatment, not a bit of difference with the smoke. The rough idling barely improved. The old plugs were pretty burn up though.

    Ok so I started asking around. Some people said could be a bad oxygen sensor, a bad MAP sensor, PCV valve, or maybe a fouled injector or something. But the scariest thing I got was word from a Cadillac "specialist" at a Chevy dealership, he said that it most likely is the distributor shaft. I say scary because that takes like 3+ hours of labor to fix (mo-money)!

    Now I have walked into the world of forums at the mercy of experienced users, mechanic, enthusiasts, freaks, and God knows what else.

    Someone please help!!! I'll be checking in this thread constantly for answers.

    Thanks!!!

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    betterlife18 is offline Cadillac Owners Member
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    Re: '91 Brougham 5.7 - 153k mi - just bought - black smoke/smog - HELP!

    ***Also forgot to add a piece of information. I ran the ECM diagnostic thing by holding OFF and WARMER at the same time (A/C control) and it came back with code 132, which I looked it up and it shows to be a FAILED KNOCK SENSOR. Could this have anything to do with my black smoke/rough idling issue?

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    90Brougham350's Avatar
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    Re: '91 Brougham - 153k mi - black smoke/smog - HELP!

    Alright, first things first, pull some codes and let us know what you find, many of us have service manuals so we can tell you exactly what's wrong. Search around the forums and read how to post the codes. If nothing comes up, can you give us more detail about the problem, ie only when cold, when hot, when exactly the ses light comes on. Let us know, I'm sure NODIH will be a big help on this one. Welcome to our addiction, by the way.

    Brian

    If you don't want to or can't find how to pull the codes, just ask! Good luck!

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    betterlife18 is offline Cadillac Owners Member
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    Re: '91 Brougham - 153k mi - black smoke/smog - HELP!

    Um, by pulling the codes, if you doing so by holding the OFF and WARMER buttons on the A/C panel simultaneously and waiting for the codes, I already got that (Code 132 - Knock Sensor Failure). Otherwise, I have no idea.

    It doesn't matter if it's a cold start or a warm one, it acts up, BUT the longer you let it sit running, the more it misses. What do you mean by "pulling the codes"?

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

    Welcome to the Addiction!

    I wouldn't trust the O2 at this point, if the exhaust is that bad, the O2 is probably dumb at the moment, but likely still good, they will "heal" if they get hot again and get some exhaust blowing through them for a while. O2's fail rarely, most are changed and gain nothing. Most often something else is causing it.

    bad oxygen sensor---It could be a cause, but most aren't bad, use discretion
    a bad MAP sensor----This will toss a code right away and run like do do.
    PCV valve-----------PCV stuck will make it lean and the ECM will compensate, likely it will toss a code for one. They are $3 to replaced. Do it every year or 2 to be sure.
    fouled injector or something--Maybe, but it will run way lean, rarely do injectors fail running wide open. But if it did, it would run poorly and black smoke. Take the air cleaner off and look down the throat of the throttle body, look for 2 uniform spray patterns. A timing is helpful, but remember, you are deailing with pressurized sprays of gasonline! BE CAREFUL!!! PEOPLE HAVE CAUGHT their cars on fire messing with the TBI injector doing silly things like smoking or something that causes a spark near it.

    Check the cap and check the firing order. It will run rich if the order is off. #5 and #7 are easily swapped. 1-8-4-3-6-5-7-2, with #1 being the front drivers side closest to the left side headlight (drivers side). Then # 2 on the opposite side, and # 3 next to #1, etc. I had my 455 Pontiac like that for a while, didn't realize it, but I just couldn't nail the 4BBL's, it would backfire then, else, it ran good and got 12 mpg city. Love big engines!

    Good choice on the plugs, they others are a waste of $. I have never seen documented a single ounce of power or efficiency more than stock AC Delcos. Most peoples claim is they run better compared to BAD plugs they took out! Good comparo, eh?

    Run 87 octane, it doens't need 91-93, and the exhaust is slightly cooler with it, so you would be better off with 87 octane. There isn't any more BOOM in the higher octane, only more resistance to pinging, which your car shouldn't have a problem with.

    Check the timing, base time off can screw with a lot.

    See what codes are being sent, there should be some.

    Do you know much on electronics? If so I can help more by having you troubleshoot more of the sensors like the O2. I would be curious to know WHY the mechanic thought the distributor shaft might need attending too. They either work or don't. And when they don't, it is broken in pieces. They do twist with too heavy weight oil over time (like 20W50 in the winter, etc), and that will effect the cam/ignition timing. But no way to the extent you are having.

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    betterlife18 is offline Cadillac Owners Member
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    Re: '91 Brougham - 153k mi - black smoke/smog - HELP!

    Ok thanks for the update. BTW I've got Mobil 1 15w50 in there now, changed it about a week ago. I did make sure the plug wires were plugged into the correct places. I'm glad to hear that you believe the dist shaft isn't jacked up, cause that's expensive to work on I hear! I'm thinging about taking it down to an Iraqi car mechanic I know of, he's real cheap, and he changed out my dad's Oldsmobile Delta's water pump for cheap. Really the only thing close to advanced I have ever done under the hood of a car was changed plugs and wires and a few oil changes . I don't have the proper tools to take out an O2 sensor.

    If I were to go buy some parts and take them to the mechanic fella I am talking about, which would you suggest I buy? Both oxygen senors, PCV valve, and what else?

    Thanks!

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

    Alright, a bad knock sensor on this engine wouldn't cause the kind of problems, but it should be replaced if it's bad. Normally the knock sensor is recognized by the EST module. If the module doesn't see a knock sensor, it will retard the timing back to HEI timing, which is very little compared to what the engine wants. You won't get detonation, but you won't get any power either. However, that would explain the intermittent SES light.

    I would change the cap and rotor. Chances are that if the plugs were bad, the inside of the cap is gonna be just as bad if not worse. 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.

    Like NODIH said, the 02 sensor rarely goes bad, but if you're intent on replacing it, just cut the wire as soon as it leaves the 02 sensor. Put a 7/8th deepwell socket on and remove the sensor while the exhaust is still warm. This is key.

    I have a feeling that the mechanic told you it would be a "distributor shaft" because he just didn't want to fix it.

    Are you going through oil? Has the catalytic converter ever been replaced? What else can you tell us? Good luck, we'll figure it out!

    Brian

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

    I would run 10W40 in summer and 10W30 in winter. Take it from someone with a truck and the same motor at 291,000 miles and the original motor thats never been cracked open.

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

    Ok guys, this is good stuff, keep it coming!

    I had originally bought a distributor cab and rotor when I bought the plugs and wires. After the change of plugs and wires and not being any difference, I decided to just not change them (prolly a bad decision). Today I took the cap and rotor back in exchange for a new PCV valve (got money back of course). The old valve was really filthy and clobbered up with what appeared to be cooked/baked on grease or oil. Put the new one in in about 15 seconds. No difference in the black smoke or rough idling, etc.

    BTW, I have no idea what an EST module is .

    I called my dad up to tell him the progress so far. He said that the intake or whatever it is underneath the air filter might just need a good blowing out with some B-12 Chemtool, or some other carb/choke cleaner:

    Bad or good idea? (doubt a dirty intake would cause so much black smoke that's extremely gritty and sticks to the driveway)

    If you guys think that the O2 sensors are 99.9% NOT the problem then tell me and I won't spend money on them. Budget is extremely tight right now!

    Oh and about the oil. It hasn't burned one drop. When I bought the car, it had been about 11,000 miles without an oil change and it was topped off. It was thick and black as tar ( what retard waits that long for an oil change), but it wasn't low at all.

    Bring on the goods!

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

    Your dad is right, a good Seafoam or Chemtool job wouldn't be a bad idea. Either slowly pour it into the throttle body or remove the PVC valve and stick the vacuum line into the can and let it suck it out. The vehicle will run either really terribly or it will die. Go through the whole darn can. Some people say to use half doing this and pour the rest into the gas, just buy 2 cans. If the vehicle won't die, you'll have to shut it off. If it dies, just as well. Let it sit for 15, 20 minutes. Start it up and let it idle. Be ware, the neighbors may not enjoy the opaque massive black cloud that swollows dogs and small children, but boy is it fun to see!

    I would head back and get the cap and rotor. After all, the juice can't flow well through the wires and plugs if it's having a difficult time even getting through the cap.

    The EST module is a little black thing, it's about an inch by an inch by an inch, and sits right behind the air cleaner. It's right next to the MAP sensor, which has a vacuum line coming out of it running to the throttle body. It (the EST module) should have 4 wires coming out of it.

    Brian

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

    LMAO, massive black cloud, I love it.

    Ok so I should unplug the PCV valve hose and stick it in the can of Chemtool and just let her run. And maybe pour a little into the throttle body. Dang I hope that would clear things up, I really can't afford to pay $60/hr for labor

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

    Have you checked the cap and rotor? What do they look like? Any pics? This could be your problem if your Sea Foam or whatever you use doesn't do the trick.

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

    Quote Originally Posted by betterlife18
    LMAO, massive black cloud, I love it.

    Ok so I should unplug the PCV valve hose and stick it in the can of Chemtool and just let her run. And maybe pour a little into the throttle body. Dang I hope that would clear things up, I really can't afford to pay $60/hr for labor
    Yup, that's an easy way to do it. Some people say use the brake booster line, but that doesn't get it anywhere near even to all the cylinders. The PVC line might not totally either, but neither does pouring it into the TBI, but both of these are better than the brake booster line.

    Brian

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

    Ok so you think I should do it in the PCV hose AND the throttle body as well? I haven't gotten my check yet, so don't have a dime to spend on the $3 bottle of Chemtool . Tomorrow I shall do it. So I need in depth instructions on what to do with the Chemtool!

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



    Woohoo! I just got me a can of Seafoam and put it to work. Stopped by Autozone, twas $6.xx. In the parking lot I poured about three ounces in the PCV hose and about five in the throttle body. Cranked it up, gave it some gas, looked behind me, was speechless. Looked like this:



    LOL! It was all white, not black at all, extremely thick, and it freaked some people out. I started to drive it back home after it cleared up a bit. When I got home (5-6 miles later) I poured the rest of it (1/3 can) into the throttle body and let it run for just a few seconds. Letting it soak into the valves real good for a half-hour or so. After that, gonna go run the rest of it out. Not sure if I have eliminated my black smoke issue cause it's too dark to see, but the SES light is still on and it hesitates when I accelerate. Tomorrow I'm picking up a rotor and distributor cap and taking it to a shop for someone to replace it, and check out the rest of it to see what is wrong. When that all gets done, I'll return with all of the suspense.

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