1994 Eldorado sometimes misfiring. Water in the Fuel?
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 1 of 2 1 2 LastLast
Results 1 to 15 of 25
Northstar Engines and System Technical Discussion Discussion, 1994 Eldorado sometimes misfiring. Water in the Fuel? in Cadillac Engine Technical Discussion; Hi people. I'm new here and this is my 1st caddy. I'm happy that there is such a forum & ...
  1. #1
    rjpier61 is offline Cadillac Owners Member
    Join Date
    Oct 2005
    Location
    New Jersey
    Age
    53
    Posts
    12

    1994 Eldorado sometimes misfiring. Water in the Fuel?

    Hi people. I'm new here and this is my 1st caddy. I'm happy that there is such a forum & website. I have had it a week & it's nice but I knew there were some issues. One thing I'm looking for advice for is that the engine runs strong mostly, it has just over 81,000 miles, but once in a while it starts misfiring, back firing and spuddering and I have no power until it clears. During this time the engine coolant temp rises quickly. up and unyil it will overheat. I thought it might be water in the fuel tank but I have been treating it with dry gas. I put on about 150 miles but this symptom of misfiring has happened quite abit. Then I thought it might be a head gasket but there is no coolent in the oil, no sweet smell at the exhaust but the coolent will blow out of the overflow relief line at the coolent cap only when the engine is sputtering (over heating or not) . Head gasket? Thanks for any advice.

  2. Remove Advertisements
    CadillacForums.com
    Advertisements
     

  3. #2
    mcowden is offline Cadillac Owners Connoisseur
    Join Date
    Jun 2003
    Posts
    1,164

    Re: 1994 Eldorado sometimes misfiring. Water in the Fuel?

    Quote Originally Posted by rjpier61
    Hi people. I'm new here and this is my 1st caddy. I'm happy that there is such a forum & website. I have had it a week & it's nice but I knew there were some issues. One thing I'm looking for advice for is that the engine runs strong mostly, it has just over 81,000 miles, but once in a while it starts misfiring, back firing and spuddering and I have no power until it clears. During this time the engine coolant temp rises quickly. up and unyil it will overheat. I thought it might be water in the fuel tank but I have been treating it with dry gas. I put on about 150 miles but this symptom of misfiring has happened quite abit. Then I thought it might be a head gasket but there is no coolent in the oil, no sweet smell at the exhaust but the coolent will blow out of the overflow relief line at the coolent cap only when the engine is sputtering (over heating or not) . Head gasket? Thanks for any advice.
    You should get a cylinder pressurization test done. They (or you) make an air hose fitting from a hollowed out spark plug, turn over the engine to close the valves for the first cylinder you will test, then hook the cylinder up to 120 PSI shop air. If it holds 120 PSI, that cylinder is good, move on to the next. It will take some time, but it's a definitive test. A shop can also test for hydrocarbons in the coolant, which is a pretty good indicator but not always 100% accurate. The symptoms you're describing do sound a lot like a head gasket leak. On the Northstar, you won't see coolant in the oil if the head gasket is blown. If it's just blowing compressed air and exhaust into the cooling system, it will become overpressurized and come out the pressure cap, like you're describing.

    Use the Search feature above and look for head gasket. You can also look in the Tech Tips forum (use the Quick Jump drop down box below). There is lots of information about this problem available.
    Mike

  4. #3
    rjpier61 is offline Cadillac Owners Member
    Join Date
    Oct 2005
    Location
    New Jersey
    Age
    53
    Posts
    12

    Re: 1994 Eldorado sometimes misfiring. Water in the Fuel?

    Michael,

    Thank you very much for the quick responce.

    Ron

  5. #4
    Ranger's Avatar
    Ranger is offline Cadillac Owners Member
    Automobile(s): White Diamond '03 DHS (with DTS floor shift)
    Join Date
    Jun 2004
    Location
    Woodstock Ill.
    Age
    66
    Posts
    73,861

    Re: 1994 Eldorado sometimes misfiring. Water in the Fuel?

    When the cylinders are pressurized also look for bubbles in the surge tank (not what you want to see).

  6. #5
    rjpier61 is offline Cadillac Owners Member
    Join Date
    Oct 2005
    Location
    New Jersey
    Age
    53
    Posts
    12

    Re: 1994 Eldorado sometimes misfiring. Water in the Fuel?

    Ranger,

    Thank you too. I suspect it's probibly a head gasket. Hope it is at least on the front head. I'm going to purchase the factory service manuals because I want to do these repairs myself. Ha..... Actually I need to do it myself due to funds.... But your help in diagnosing may help limit unnecessary dissassembly.

    Thanks again.

    Ron

  7. #6
    davesdeville's Avatar
    davesdeville is offline Banned
    Automobile(s): 1995 ETC, 75 Deville, Cad500 powered 73 Apollo, 94 Mark VIII
    Join Date
    Aug 2003
    Location
    Albuquerque, NM
    Age
    27
    Posts
    7,971

    Re: 1994 Eldorado sometimes misfiring. Water in the Fuel?

    If it is the headgasket, even if it is the front head, it's a better plan to drop the cradle and do all 20 holes. Whatever caused the front one to go is working on the back one as well.

  8. #7
    rjpier61 is offline Cadillac Owners Member
    Join Date
    Oct 2005
    Location
    New Jersey
    Age
    53
    Posts
    12

    Re: 1994 Eldorado sometimes misfiring. Water in the Fuel?

    davesdeville,

    When you're right, you're right. Might as well do it right the 1st time and get it over with.

    Thanks,

    Ron

  9. #8
    rjpier61 is offline Cadillac Owners Member
    Join Date
    Oct 2005
    Location
    New Jersey
    Age
    53
    Posts
    12

    Re: 1994 Eldorado sometimes misfiring. Water in the Fuel?

    Ok......... Here is what I feared. I got the title today in the mail. It basically sat on a used car lot since March of 05. When I got it it had about 50 miles more than the last time the title was changed in March. When I picked it up it had just over a 1/4 tank of gas. So it sat for more than 6 months with between 1/2 & 1/4 tank of gas. Can the once in a while misfiring & sputtering be caused by water in the fuel or can the coolent cause this situation on and off. I pretty much figured it has a blown head gasket because the pressure in the coolent system blows before it reaches overheating temps.

  10. #9
    Ranger's Avatar
    Ranger is offline Cadillac Owners Member
    Automobile(s): White Diamond '03 DHS (with DTS floor shift)
    Join Date
    Jun 2004
    Location
    Woodstock Ill.
    Age
    66
    Posts
    73,861

    Re: 1994 Eldorado sometimes misfiring. Water in the Fuel?

    I don't think sitting for that amount of time would cause much problems. If you are in an area that has 10% ethanol, that would dry out any moisture in the tank. If not, add a pint or so of iso-somethingorother alcohol or an over the counter gas dryer to the tank to be sure. That would eliminate that that possible cause.

    Oops, rereading your first post, I see you've already covered that base. BTW, Northstars rarely get coolant in the oil through a blown head gasket like a conventional engine, so don't look for that symptom.

  11. #10
    rjpier61 is offline Cadillac Owners Member
    Join Date
    Oct 2005
    Location
    New Jersey
    Age
    53
    Posts
    12

    Re: 1994 Eldorado sometimes misfiring. Water in the Fuel?

    Ranger, ok thanks. What about possible coolent being sucked into the cylinder. Would it still fire correctly? It does fire fine mostly with plenty of power but just that every once in a while it's like I just sucked in water into the intake. It takes a while to clear the engine then it runs fine for a wile then starts again. Guess taking it one step at a time. But man!!!! I don't have a service manual yet but have been poking around online trying to fine a procedure on head gasket replacement with little luck. But what I see from some pictures, this is a design I'm not used to. I have done engine work years ago on 340 ci Mopar, 350 GM, 351 Ford but this overhead cam stuff. From the look of some cutaways it looks like I have to pull the front engine cover to expose the chains & gears. Looks like a mess and hard access. No wonder people do engine swaps.

    Ron

  12. #11
    zonie77 is offline Cadillac Owners Connoisseur
    Automobile(s): 94 ETC,97 STS
    Join Date
    Sep 2003
    Location
    Arizona
    Posts
    3,531

    Re: 1994 Eldorado sometimes misfiring. Water in the Fuel?

    The head gasket job isn't that bad. If you've done work on other v8's you should be able to handle it.

    There's a thread in tech tips that gives a lot of info. Read it. If you ever timed a v8 cam you can handle timing 4 at once.

    It is hard to access "in the car". Drop the cradle and it's much easier. This is the curse of FWD. Not just Caddy but all FWD's are harder to work on. Make it a v8 and it gets REAL hard. It's just a matter of available space.

    Your question about intermittent leaking. Yes, that's what sends most people to left field. You do something and it seems to fix it , then it overheats again, do something else and it works awile. Eventually they get real bad.

    I try to get people to test for headgaskets right away, not because I think they all blow, but to save them from shotgunning an overheating problem that's really gaskets. Sometimes it is a radiator or purge line...sometimes gaskets. It's just doing good diagnostics and not spending a bunch of money unnecessarily.

  13. #12
    Ranger's Avatar
    Ranger is offline Cadillac Owners Member
    Automobile(s): White Diamond '03 DHS (with DTS floor shift)
    Join Date
    Jun 2004
    Location
    Woodstock Ill.
    Age
    66
    Posts
    73,861

    Re: 1994 Eldorado sometimes misfiring. Water in the Fuel?

    I think the answer to your question is maybe. A small leak would probably not affect the way it runs but a bad breach probably would as coolant is not flamable. Everything in your original post leads me to think it is not a head gasket, except for the overheating. I think you need to do the cylinder pressure test to confirm or rule out a head gasket for sure.

  14. #13
    rjpier61 is offline Cadillac Owners Member
    Join Date
    Oct 2005
    Location
    New Jersey
    Age
    53
    Posts
    12

    Re: 1994 Eldorado sometimes misfiring. Water in the Fuel?

    Zonie77, Thanks for the words of encouragement. The car runs at normal temps except when it starts misfiring and sputtering. After the episode it drops back to normal.

    Ranger, thanks again. I am going to go that route and pressure each cylinder. Should I go the 120 psi to eash cylinder route or 15 psi at the coolent cap method? I pretty much know what to do & what to look for on both methods but the 15psi seams easier but less reliable. I kinda think the individual 120 PSI on each cylinder would better narrow it down...

    I'm going to do this this weekend.

    Thanks guys!

    Ron

  15. #14
    rjpier61 is offline Cadillac Owners Member
    Join Date
    Oct 2005
    Location
    New Jersey
    Age
    53
    Posts
    12

    Re: 1994 Eldorado sometimes misfiring. Water in the Fuel?

    Zonie77, Thanks for the words of encouragement. The car runs at normal temps except when it starts misfiring and sputtering. After the episode it drops back to normal.

    Ranger, thanks again. I am going to go that route and pressure each cylinder. Should I go the 120 psi to eash cylinder route or 15 psi at the coolent cap method? I pretty much know what to do & what to look for on both methods but the 15psi seams easier but less reliable. I kinda think the individual 120 PSI on each cylinder would better narrow it down...

    I'm going to do this this weekend.

    Thanks guys!

    Ron

  16. #15
    Eldyfig's Avatar
    Eldyfig is offline Cadillac Owners Connoisseur
    Automobile(s): 13 Challenger RT, 11 CTS Coupe Premium, 94 Eldorado (RIP)
    Join Date
    Jan 2003
    Location
    Folkston, GA
    Posts
    1,306

    Re: 1994 Eldorado sometimes misfiring. Water in the Fuel?

    I see everyone is on the subject of headgasket, this is a big paranoia with North*s. Like Ranger said, I doubt your misfiring is a headgasket problem. First thing to check in any misfiring case is your plugs, then wires and coil packs. I didn't see any mention of this from your post. Have you checked them?

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