SN95 95 Mustang Gt Loud

Discussion in '1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-' started by jmil918, Mar 24, 2014.

  1. I seem to have developed a loud knock in my engine. I posted a video in the link below and I know the valve train is chattering quite a bit, but its the loud single knock that I'm concerned about. Also, ignore the smoke, I had spilled some oil on the headers prior to start up. Any help would be greatly appreciated!


    Thank you
  2. It sounds like rocker tap.

    You getting any codes? Run a cylinder balance test.
  3. Noobz has good advice in a cylinder balance test. It will soumd like hell but should tell you which cylinder is the culprit. To confirm, take a wooden dowel, plastic pipe, stethoscope, or even a long hammer and place it on the valve covers on each side and the other end to your ear. Try and listen to where the sound is coming from. You could have either a bad lifter, a bad rocker, or bad valve spring. Once you've isolated the side and which cylinder, then you can pull the VC.
  4. I haven't used the stethoscope yet, plan to tomorrow. But when I put my hand on the valve cover I didn't seem to feel anything, but when I put my hand on the upper intake I could feel when whatever is happening happens. I'll let you know the results of the stethoscope, but could this mean something more serious, like a rod knock?

  5. Anything is possible and can't be ruled out by us while listening to a video. I tend to think that the problem is more along the lines of what Mike and I have stated above. The only way to really rule it out is to start eliminating possibilities.

    It's time to start systematically looking for the problem vs. spit-balling worse case scenarios. We can't get any directional information from the clip but it does sound like a top-end problem.
    A5literMan likes this.
  6. Ok, I plan to go through your suggestions today after work. Obviously I would be pulling off the VC before I got too crazy with any other possible scenarios so if it is in the top in it should be relatively easy to find. I will let you know what I discover.

    Thank you for the help
  7. I finally got around to pulling off the spark plug wires to see how it changed the idle. When pulling off the plugs one at a time, none of them seemed to make the knock go away, based on some research that makes it sound like the knock is in the top. Also, I noticed about a 200-250 RPM drop when pulling every plug except 5,6, and 7. When I pulled each of those plugs there was no change in performance. Any ideas what that means?

    Spark is still good for each wire, and the plugs are almost brand new.

    I was told that this could be caused by an intake/vacuum leak or possibly too high of an idle, not sure how reliable that info was though. I plan to check the gasket on the intake next, but wanted to see if anyone had any thoughts to add...
  8. I don't see the results of any codes scan or the result from a cylinder balance test.

    There's also no indication that the valve covers have been pulled in order for a visual inspection of the valve train.
  9. I posted the results of the balance test above, its all I've had time to do as I made very clear in my post. I was simply asking a question about the results of those tests and to see if there was any USEFULL information someone could give me. I'm not sure what sort of self satisfaction you got out of your post, clearly I said I was going to perform the other tests I just haven't got around to it, in the mean time I thought maybe someone could speculate on the results of the balance test. I would rather do trial and error than ask for help from someone that replies as you do.

  10. If all I were after was self-satisfaction, I would nuke your thread and your account into oblivion.

    There is one small inescapable portion of assisting with technical troubleshooting over the internet:

    We require USEFULL information in order to help you. So far you provided one small piece. Plugs 5, 6, and 7 do not appear to change your idle RPM. That information goes to indicate one thing... You STILL need to do a cylinder balance test so that the EEC can narrow the problem down to specific malfunctioning cylinder. A code scan can further indicate if there is an injector or sensor malfunction.

    So... Instead of trying to take out your frustration on folks who are attempting to assist you in diagnosing your problem, I see 3 possible choices for you:

    1. Fix it yourself
    2. Hire someone to fix it for you
    3. Try to provide the requested information so that we have a direction in which to try and point you

    If you're not sure how to do a cylinder balance test then you should indicate that or do a search of the forums for the steps necessary to accomplish this.
    mikestang63 and A5literMan like this.
  11. Not to sound harsh, but I would recommend in the future you check the ego at the door. You came here asking for help, and getting an attitude with someone like Noobz who has helped more people than I can count, is not going to endear you with people jumping in to help.

    I can't see where you posted the results fom a cylinder balance test either.
    A5literMan likes this.
  12. PULL THE VALVE COVER. 10 min and you will SEE the problem. PS you have multiple valve train issues or you are running a solid flat tappet cam.