90 coupe deville in need of a fine tooth comb...
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Cadillac DeVille 1985 to 2005 including:
1985-1992 Fleetwood, 1993 Sixty Special, All FWD Forum Discussion, 90 coupe deville in need of a fine tooth comb... in Past Cadillac Vehicle Discussion; Hey everyone, Names nick. Been on the forum for a lil while now trolling through numerous threads hoping I'd find ...
  1. #1
    afronippleyo is offline Cadillac Owners Member
    Automobile(s): 90 Coupe deVille
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    Feb 2013
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    23
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    90 coupe deville in need of a fine tooth comb...

    Hey everyone, Names nick. Been on the forum for a lil while now trolling through numerous threads hoping I'd find something To ultimately cure my car's problems. I have found a lot thats helped me but still having issue...

    A little back story on the car...
    We bought it from a tow yard for $1000 purring like a kitten. When it came time for smog, I did the usual tune up, oil change, etc. She ended up failing just barely so I decided to let the shop do their diagnosis... Ever since then, It's run like complete $#!t and gradually getting worse. They told us the camshaft sensor and the cat needed replaced. We never took it back...

    Now, some time later, after a few other shops looking at it, they all said the cat was fine... that it was something electronic.

    Since then, I've replaced the halleffects sensor (which was shattered b/c the tab in the dizzy was bent) Performed an audible test on the injectors, checked all vac lines I could find, checked connections at the ecm and went over the ignition system(plugs to rotor). The halleffects sensor cleared the check engine light and dramatically helped how it was running but still not what it should be. All the vacuum lines looked and felt fresh and werent clogged. The plugs at the ecm were ok but the ecm itself isnt bolted down(isnt that the ground??). All the injectors sounded fine, no irratic or missing clicks. I didnt pull all the plugs but the ones I did pull looked like the car is running rich. #1 wire was split and has no connectivity when tested with an ohm meter but it looked like it was still firing in the cylinder.?.? Replaced that wire to test and it made a VERY subtle difference.

    I havent replaced the plugs & wires yet. I want to test the coil 1st. Other than checking the injectors for leaks/clogs, I'm pretty stumped. I plan to check the resistance for the injectors at the ecm but when I wrote down which wire is which I forgot to write down the common wire and havent been able to find the info since.

    What should I add to the list next? Any ideas?

    Also, a couple other things. Is there anywhere on here where I can find wiring/vacuum diagrams? I tried the on-board diagnostic thing with the fuel data center and the climate control center and maybe I'm doing something wrong? the function and layout was nothing like what the sticky says it should be... What am I doing wrong? Lastly, I noticed an air line on the air compressor was disconnected. Anyone know where the hell it goes?

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  3. #2
    Manic Mechanic is offline Cadillac Owners Fanatic
    Automobile(s): 2001 DeVille
    Join Date
    Sep 2011
    Location
    Magnolia, TX (NW of Houston)
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    Re: 90 coupe deville in need of a fine tooth comb...

    Hey Nick,
    You've said a good bit (which is great) so I need to try and narrow it down some.

    1. Which gas(s) did you fail for? Do you have the report showing which gas, the limit and your test result? That tells someone who may know what to look for.

    2. You said you did the usual tune-up first but you haven't replaced plugs and wires yet? That's a significant part of a tune up for that car and you even found one cable that was open circuit. Lucky for you the gap in the cable was still small enough that the coil was able to jump it some, but it added to the ignition coils load for that one cylinder just like a larger plug gap. Stuff like that causes misfiring and ruined cats. Replace all plugs and the wires before looking any further.

    As for 1990 specific info I'm out, I only know a 2001 style inside and out now.

    Vernon

  4. #3
    dennis93coupe's Avatar
    dennis93coupe is offline Cadillac Owners Connoisseur
    Automobile(s): 1993 Coupe Deville 2006 XLR Infrared, Ebony
    Join Date
    Feb 2010
    Location
    Orange County, CA
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    60
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    2,468

    Re: 90 coupe deville in need of a fine tooth comb...

    You don't by chance have a FSM? If not ebay is your friend. Also you mentioned an airline on the compresor. What compressor? The AIR compressor?

  5. #4
    afronippleyo is offline Cadillac Owners Member
    Automobile(s): 90 Coupe deVille
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    Thread Starter

    Re: 90 coupe deville in need of a fine tooth comb...

    Vernon, ill get back to you when I get home. That's a lot of typing for a phone. Haha.

    Dennis, yes the air compressor. For the rear shocks if I'm not mistaken. I assumed the shocks were just old and worn until I noticed that.

  6. #5
    afronippleyo is offline Cadillac Owners Member
    Automobile(s): 90 Coupe deVille
    Join Date
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    Thread Starter

    Wink Re: 90 coupe deville in need of a fine tooth comb...

    Sorry vernon for the delay, I've been busy. Anyways, the car failed the functional check (Ignition timing-Mech problem and SES light) and Emissions (CO[MAX/MEAS]15MPH-.49/.89 25MPH-.40/.81). HC was pretty close to max but still within specs([MAX/MEAS]15MPH-75/65 25MPH-57/54) and NOx is way below average ([AVE/MEAS]15MPH-297/172 25MPH-259/130). Keep in mind this isnt the 1st smog we have got. We jumped through a couple hoops to get the car temporarily legal and as part of that we had to attempt to smog it again. These results are from 12/21/2012

    Yesterday I found out what I needed to test the Ohms again and finally got that done. The results were rather shocking. From what I read, the Ohms are supposed to be within 15.8-16.6...
    They measured...
    1-7.7
    2-17.0
    3-9.0
    4-15.2
    5-15.9
    6-9.9
    7-11.5
    8-7.7

    Think I might have found my problem? haha. Later today I'm going to pull the fuel rail and harness and test the resistance at the injectors just to make sure it isnt a wiring issue. I'm narrowing it down guys!!

  7. #6
    afronippleyo is offline Cadillac Owners Member
    Automobile(s): 90 Coupe deVille
    Join Date
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    23
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    Thread Starter

    Re: 90 coupe deville in need of a fine tooth comb...

    Thanks for the support on here guys...

    Anyways, I lucked out and got a set of used injectors for free. All in between 17.3-17.6. After a few curse words and a rather nasty fuel leak, I have it back together and for the most part, running right. Right now the problem I'm dealing with is the idle. I think I Fu(ked up the idle controller while I was reinstalling the fuel rail and now, unless I'm at a stop, it idles high enough to hold 31mph in 2nd gear. I have a spare so I'm going to install it and see where it goes from there.

    As for emissions, I had a friend of mine who works at a smog shop stick the sniffer in the tailpipe just to see where I stand and it was below max. Not by much but still passable so as soon as my finances are caught back up, It'll be completely legal finally!!

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