Serious problem, loud knocking, now car won't start

Posted by SinaiTSi, Nov 4, 2005
Newbie Forum - Beginner DSM modification questions and discussions. Common, repetitive, and general discussions will get dumped here from other tech forums. Unless you're a Probationary member you shouldn't post threads here.

  1. SinaiTSi

    SinaiTSi Proven Member

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    Misawa, Japan, Asia
    When I got home today, I decided to change my rear diff. fluid. The only thing I did was just drain the fluid and put more in. Well, when I go to turn the car over, there is this extremely loud knocking sound that sounds to be coming from within the engine. I turn it off and turn the car over once more, and this time it dies. Well, then my dad turns it over to see what the problem is and as it's dying he revs it to like 6k rpm and then the cars dies for good. Now the car won't start at all, it tries but won't start. Timing belt looks to be fine, as in not broken, I didn't do a real good inspection of it but I really need help on this. I think something serious is wrong, if you could please let me know what you think the problem is. Thanks a lot.
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  2. hova

    hova Proven Member

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    when your dad rev the engine was it knocking, if not then its a tranny problem, check your flywheel and starter, thats all i got hope its not your motor! goodluck
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  3. Defiant

    Defiant DSM Wiseman

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    glorious Galt, California
    Jumped timing, bent valves. Thanks, dad.
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  4. SinaiTSi

    SinaiTSi Proven Member

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    Misawa, Japan, Asia
    no, when my dad reved the engine, it knocked really loudly. I'm thinking defiant is right.
    But one question, I just had a burnt valve fixed and replaced a few months ago when the car was missing, what do you suggest I do now that it seems like some of the valves are bent. should I try to fix it myself or what and how much money am i looking at.
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  5. Julioluko

    Julioluko Proven Member

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    Well if you bent a valve you might have just ruined a piston too, and if you did just skip your timing you've also probally messed a piston up. WTF The best thing you can do is go and get yourself a compression tester. It's basically a high pressure gage with a hose and it screws into your spark plug hole. Then you screw it into your spark plug hole and turn the engine over about 4 times and the gage should say around 155, i think the service limit is 138-140(someone correct me if I'm wrong). Do this to each cylinder and see what you got. If one or more cylinders is out of wack you found your problem. Take luck
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  6. Julioluko

    Julioluko Proven Member

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    Oh and i don't know where you live but you can pick a compression tester up at Advance Auto Parts for 25 bones. I would highly recommend getting one because you can use it on any car and its a good way to determine the condition of an engine. Sorry if i over explained things a bit, i don't know how much mechanics you know, but good luck and since your dad broke it you might want to have him fix it LOL :sneaky:
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  7. SinaiTSi

    SinaiTSi Proven Member

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    Misawa, Japan, Asia
    So if I do go get a compression tester and find that one or more of my cylinders does have a problem. What do you suggest I do?
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  8. SinaiTSi

    SinaiTSi Proven Member

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    Misawa, Japan, Asia

    I checked the timing last night and the marks match up perfectly. If the timing is correct, what do you suggest??
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  9. 6 bolt TSi

    6 bolt TSi Probationary Member

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    Check the compression as stated above to see what your compression numbers are. This will tell you if you bent a valve. If you were just sitting in your driveway, I don't think it would have been possible to toast a piston as the EGTs wouldn't get nearly high enough. You could have nicked it, which could result in hot spots and pre-detonation when on-boost. Use a strong focussable flashlight and look down the plug holes to the surface of the piston. There are some normal semi-circular marks that should be there for clearance, but no sharp edges.

    Cheers
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  10. SinaiTSi

    SinaiTSi Proven Member

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    In the directions for the compression test, it says run car to normal operating temp. well..... I can't even get the car to turn over, will it still work right if I don't have it up to normal operating temp. first??
    If not, then how do I check the compression?
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  11. SinaiTSi

    SinaiTSi Proven Member

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    ok.....this is what i know so far. I just did a compression test on a cold engine. As I stated above, it says get engine to normal operating temp but I can't. Well, on cylinders 4 and 3, the gauge just bounced around at about 5 psi and that was it. Cylinder 2, compression got up to 60 psi and stayed there, and on cylinder 1, the guage showed no reading at all. I'm almost positive I'm getting spark because wires were pulled with a plug and indicated spark. Plugs are gapped correctly. I'm getting fuel because when I try to start the car, and it just spins, I take the plugs out afterwards and they have gas all over the tip. But, everything just spins, the car never turns over. What do you think could be wrong then, does this sound like I need new valves???
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  12. SinaiTSi

    SinaiTSi Proven Member

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    Misawa, Japan, Asia
    Ok, I made a post about my car not be able to start after a horrible knocking noise, here: http://www.dsmtuners.com/forums/showthread.php?p=1699662#post1699662
    I am almost positive now that I bent some valves and I'm going to need to pull the head. My only problem is that I don't want to replace the head/valves and just have them get damaged again. My question is what can cause bent valves. Also, I know incorrect timing can but I checked my cam gears and they line up perfectly like they should. Thanks
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  13. ImportModder

    ImportModder Proven Member

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    That is the only way to bend valves. If everything is timed correctly, there will be no interference of the valves and pistons. Did you recently do a timing belt change? If so, is the tensioner new or used? If used, it could be bad and not tension the belt correctly resulting in getting off-timed and bending valves.

    Other than that, I don't know what to tell you. Double check and then re-check the alignment.
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  14. Old Mitsu Tech

    Old Mitsu Tech DSM Wiseman

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    Well, let's see. Horrible knocking noise? I have seen on here a picture of one valve that just dropped the falve face off the stem. This will immediately destroy the head and piston as it's much too large not to do so. Having cams line up is only one part. You have to make sure the crank is in the proper position. If it's not then the piston is trying to occupy the same space at the same time as the valves. This won't work. This is an interference fit engine. Usually if the teeth are machined off the belt it's almost always at the crank as that's the smallest surface area the belt runs on. The cams have twice as many teeth as the crank thus giving more support to the belt.

    Do a compression test, if you have a dead or no compression cylinder, remove the timing belt cover and inspect. If it lines up you may have the first disorder, if it doesn't then you probably have the latter. Now you probably need to pull the head at this point or borrow/ rent a bore scope to look down into your spark plug holes if you don't want to pull the head. If you see something that resembles scrap metal then the head has to come off. Good Luck
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  15. 92awddsm

    92awddsm DSM Wiseman

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    Chesterfield, Virginia
    Well, by the other thread, It definately sounds like bent valves. I am going to be up that way Satuday for a party. I can come up early and take a look at it and tell you what the problem is if you are interested. And since you are from the burg, you should check us out. www.team-trinity.com
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  16. SinaiTSi

    SinaiTSi Proven Member

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    Well, what makes me so mad about this is that I just had some headwork done about 4 months ago because of a burnt valve. The shop where I had it done also replaced the timing belt. So what you're saying is that they must've screwed something up which caused this? I did have a freind come look at the car and suggest that the tensioner wasn't correct since the cam gears line up. I did a compression test and got cylinders 4 and 3 bounce around at 5 psi. Cylinder 2 was 60 psi and Cylinder 1 showed no reading. So i'm gonna pull the head and asses the damages. I know somebody that can help me with this and they've done it before, so what you're saying is, as long as i have all of the timing straight when I do this, my car should be fine?
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  17. Old Mitsu Tech

    Old Mitsu Tech DSM Wiseman

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    Well, you 're going to love this.

    Perfectly adjusted timing belts can and do fail for no reason other than they were manufactured wrong. New valves can and have come apart for reasons totally beyond me. New tensioners have gone bad, new idler pulleys have seized up due to manufacturing defect.

    Now that's out of the way and really screwed you up,

    If the timing belt is installed perfectly right you are only decreasing your chances of something going wrong. It is in no way an assurance of many happy miles of driving.

    We are only telling you to replace everything that has given problems in the past due to age and miles. This we know gives problems. New parts? Well, you have a piece of paper that's called a sales receipt. New parts carry a warranty. Warranty means in the event of a failure during the warranty period the part will be replaced according to the sales agreement on said part.

    In some cases if the part has been installed professionally the collateral damage is also covered. This is on a case by case basis and must be determined by the seller of the parts or the installer of the parts.

    Using old and hi milage parts is like running nude through a Turkish prison. You can do it and get away with it for a while, but if you make a mistake and get caught, well you know the drill.

    New parts only increase your chances of a good rebuild. You have a warranty, not a guarantee. There's a difference.

    I know this is probably confusing but it is a real world thing.

    Good Luck
    #17
  18. HighPSI TSi Guy

    HighPSI TSi Guy Proven Member

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    Did you redo the compression test following the instructions i gave you? The timing belt felt tight and the cams are lined up, however, the crank sprocket COULD have jumped, though with the good tension, i don't know how. we can check that before pulling the head, since the same sh**'s gotta come off before the head comes off anyways.

    my guess remains that it is something in the head. Let me know what your new numbers are form the compression test doing it the way i gave you, and get in touch with me, i might be able to take another look this weekend.. the 10 minutes or so the other night wasn't really enough time to look at much. an opinion from keith "92AWDDSM" would be helpful too, always good to have extra brains thinking...

    I have to tune a car on the dyno saturday afternoon but if i have time around that maybe the 3 of us (keith, you, me) could look at it together and maybe 3 brains can come up with an answer quicker, i gotta get some sh** from keith anyways i think?
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