1990 Deville running poorly.
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
Results 1 to 10 of 10
HT4100 4.1, 4.5, 4.9 Discussion, 1990 Deville running poorly. in Cadillac Engine Technical Discussion; I have a 1990 Deville with the 4.5 Liter. I had a lot of problems with it so I took ...
  1. #1
    jlarson69 is offline Cadillac Owners Member
    Automobile(s): Cadillac
    Join Date
    Oct 2006
    Posts
    19

    1990 Deville running poorly.

    I have a 1990 Deville with the 4.5 Liter. I had a lot of problems with it so I took it to a dealership and they said I had six bad injectors. So, I replace those with remanufactured ones from www.rockauto.com and it runs much better but still not perfect.
    It just falls flat on its face when you try to accelerate with more that 1/4 of the pedal down, it idles a little rough, and it dies at stop signs when the gas tank is less than a quarter full. It shows the codes 48, 49, 52, and 98.
    I've replaced the plugs and wires recently, also, when I changed the injectors.
    Can anyone help me out?

  2. Remove Advertisements
    CadillacForums.com
    Advertisements
     

  3. #2
    Raze's Avatar
    Raze is offline Cadillac Owners Enthusiast
    Automobile(s): 90 Eldo -SOLD-, 98 ETC -SOLD-, 86 XR4Ti Track Car, 07 Ranger
    Join Date
    May 2004
    Location
    Atlanta, GA
    Age
    32
    Posts
    963

    Re: 1990 Deville running poorly.

    at the top of the 4.x board is a sticky with all the trouble codes in it, I'm assuming they're all engine (E) codes? if so here's your list:

    E48 - EGR System Problem ~ clean or get a new EGR tube/valve...
    E49 - A.I.R. Control Problem ~ don't know, maybe the MAF sensor?
    E52 - PCM Memory Reset (See Note) ~ not important just means you or someone has reset the codes
    E98 - High RPM P/N to D/R in ISC Range ~ ISC sounds like it's going or gone, do you have a high/unstable idle? If so time for a new ISC motor...

    Definitely sounds like your computer is having trouble reading how much air is actually entering your engine, would explain some of your problems.

  4. #3
    awadecki is offline Cadillac Owners Enthusiast
    Automobile(s): 76 Eldo (54k), 76 Eldo (52k), 78 Eldo (9k), 85 Deville (43k)
    Join Date
    Jun 2005
    Location
    Michigan
    Posts
    668

    Re: 1990 Deville running poorly.

    Your EGR valve is likely sticking open, causing your rough idle and hesitation. If you push up on the diaphram underneath it and it doesn't move freely, it must be replaced. While you're at it, clean out those tubes in the throttle body with carb. cleaner and a coat hanger or wire brush. This should solve the E48, E49, and E98 codes. The ISC code (E98) is probably out of range because it's trying to prevent a stall because of the stuck EGR.

    Also, for $15, you may want to install a new MAP sensor--it's very easy. These tend to get lazy over time. Also, clean out the MAP port on the throttle body with intake cleaner.

  5. #4
    cadillac_tech is offline Cadillac Owners Fanatic
    Automobile(s): 2008 SRX
    Join Date
    May 2007
    Location
    Parker , CO
    Posts
    403

    Re: 1990 Deville running poorly.

    1990 model PCM's were sensitive to shorted injectors. If the resistance got very low on any of those 6 bad injectors, the PCM probably suffered damage to one or more injector drivers. You may have an EGR problem, or you may have just created one by accident while doing the injectors.

  6. #5
    Melrose is offline Cadillac Owners Fanatic
    Automobile(s): 1999 Deville, 1987 Eldorado
    Join Date
    Apr 2005
    Location
    North Carolina
    Posts
    109

    Re: 1990 Deville running poorly.

    See my post under HT 4100 backfiring.

  7. #6
    jlarson69 is offline Cadillac Owners Member
    Automobile(s): Cadillac
    Join Date
    Oct 2006
    Posts
    19
    Thread Starter

    Re: 1990 Deville running poorly.

    Thanks for the advice, guys. I'll get to it on Wednesday and let you know how it turned out.

  8. #7
    snydly402 is offline Cadillac Owners Member
    Automobile(s): 1990 sedan deville
    Join Date
    Aug 2007
    Location
    Nebraska
    Posts
    9

    Re: 1990 Deville running poorly.

    E49 is A.I.R Control problem. its the goofy looking device on top of the rear vavlve cover with all the hoses coming off of it. that valve diverts air into the front exhaust manifold and into the cat. conveter under the car. this is for emissions and i have the same code. the vavle unit is about $400, so i suggest a salvaged vavle.

    My car is acting the same except for the dieing, im think it may be the distributor cap, rotor, and possibly coil.

  9. #8
    jlarson69 is offline Cadillac Owners Member
    Automobile(s): Cadillac
    Join Date
    Oct 2006
    Posts
    19
    Thread Starter

    Re: 1990 Deville running poorly.

    I haven't got around to doing anything to it yet and it's still running about the same. I'm averaging 9 mpg with it. The only thing different now is the only code I'm getting is the E49(A.I.R. Control Problem).
    Also, the previous owner took hollowed out the catalytic converter and put it back on. Would this contribute to my problem?

  10. #9
    jlarson69 is offline Cadillac Owners Member
    Automobile(s): Cadillac
    Join Date
    Oct 2006
    Posts
    19
    Thread Starter

    Re: 1990 Deville running poorly.

    Anyone?

  11. #10
    lenny lincoln is offline Cadillac Owners Fanatic
    Automobile(s): Cadillac
    Join Date
    Apr 2007
    Posts
    102

    Re: 1990 Deville running poorly.

    clean the egr tubes in the carb inlet.take the aircleaner off and look inside to find to tubes sticking straight up. make sure they are not all gummed up.

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