Cadillac
 

Cadillac Forums | Help Us Help You | Advertise | Cadillac Parts | Cadillac News | Cadillac Classifieds

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

Page 5 of 5 FirstFirst 12345
Results 61 to 66 of 66

Thread: 4.1,4.5,4.9..Which You Prefer?

  1. #61
    Sevillian273's Avatar
    Sevillian273 is offline Cadillac Owners Connoisseur
    Automobile(s): 69 Thunderbird | 90 Seville | 89 Marquis | 72 Torino
    Join Date
    Oct 2008
    Location
    Palm Bay, FL
    Posts
    2,024

    Re: 4.1,4.5,4.9..Which You Prefer?

    The larger injectors are fooling the computer into believing that the car is going farther on a given amount of fuel. It expects a certain flow rate (stock injectors) and calculates based on that. I've run into this myself when I was using 19lb injectors over the stock 16lb units. I was mystified by the discrepancy between actual and displayed mileage until last year when drewsdeville pointed out to me that the computer was not taking the un-metered fuel into account. ('un-metered' fuel being the difference between the flow rate of the stock units and that of the larger units.) Calculate the actual mileage using the odometer and you will be unpleasantly surprised!

    Last edited by Sevillian273; 04-17-11 at 11:15 PM.

  2. #62
    drewsdeville is offline Cadillac Owners Master
    Automobile(s): 2011 Crown Vic LX, 2009 Chevy Malibu 2LT
    Join Date
    Oct 2004
    Location
    Oak Creek, WI
    Posts
    5,607

    Re: 4.1,4.5,4.9..Which You Prefer?

    ^^^That.

    You just installed injectors that flow about 15% more fuel over time. The PCM doesn't know this - all of it's algorithms are static. Now dynamic fuel adjustments made by the PCM will be off by about the same percentage, as pulse width is being reduced to accommodate.

    15% reduction from the false 28-31mpg's is 23.8-26.3mpg's - right where it's supposed to be.

  3. #63
    sprocket is offline Cadillac Owners Member
    Automobile(s): '88 Eldorado
    Join Date
    Apr 2010
    Location
    MN
    Age
    53
    Posts
    97

    Re: 4.1,4.5,4.9..Which You Prefer?

    Well thanks for destroying my fantasy guys! Yeah, I thought the fuel gauge looked like it was dropping too fast for 29 mpg. Anyway, the car runs pretty good and is very responsive. The idle isn't perfectly smooth but maybe there is still some things I can do to improve it more. These are used, and very old injectors. Cleaning them might help. How about an adjustable fuel pressure regulator?

    Really, the idle is acceptable to me. It's not that bad.

  4. #64
    Sevillian273's Avatar
    Sevillian273 is offline Cadillac Owners Connoisseur
    Automobile(s): 69 Thunderbird | 90 Seville | 89 Marquis | 72 Torino
    Join Date
    Oct 2008
    Location
    Palm Bay, FL
    Posts
    2,024

    Re: 4.1,4.5,4.9..Which You Prefer?

    An adjustable FPR probably isnt necessary. After all, the computer is compensating for the extra fuel flow. Lowering the fuel pressure can degrade the atomization of the fuel from the injectors.

  5. #65
    ehall's Avatar
    ehall is offline Cadillac Owners Connoisseur
    Automobile(s): 1985 Sedan DeVille
    Join Date
    Aug 2007
    Location
    Southern Maryland
    Posts
    1,883

    Re: 4.1,4.5,4.9..Which You Prefer?

    Buying known-good injectors would yield the best results. A couple of bottles of Lucas fuel system cleaner would probably be a big help too but injectors can fail for a variety of reasons and fuel cleaner only addresses gummed passages

  6. #66
    still_walkin's Avatar
    still_walkin is offline Cadillac Owners Connoisseur
    Automobile(s): 1993 Cadillac deville sedan 1986 cadillac deville RIP
    Join Date
    Apr 2007
    Location
    san diego
    Age
    34
    Posts
    1,498

    Re: 4.1,4.5,4.9..Which You Prefer?

    i owned two devilles 86sdv and 93 sdv. heres my good and bad. the 86 the power sucks the coolant system isnt all that great but the engine is easy to work on . its gets better gas than the 4.9 buyut i overall like the classic look of it but i hate the hubcaps on the 86. and the 93 more power uses more gas the engine is a bit harder to work on and i love the SIR system. the extra space is great and i love the fact that it still looks elegent from todays cars. however in looks great on vogues

Page 5 of 5 FirstFirst 12345

Bookmarks

Cadillac Posting Rules

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Read about Lincoln | Buick | Kia Forte Forum