cuto Posted January 21, 2009 Report Share Posted January 21, 2009 I think i mentioned this before, but now i have a new simptom. When restarting the car, after a ride, when the engine is still warm, i can hear a knocking sound coming from the engine bay. This only happens in this situation: i park the car after a ride and stop the engine. After 10 minutes or so, if i restart the car the knocking sound appears and will go away if the car is reved a bit or by driving it. The issue is, today i found a new simptom: the same knocking sound appeared only if i set the gear in to D, S,L,R. No knocking in P or Neutral. As soon as the car was revved a bit, the knocking went away. I'm getting pretty worried and i'm afraid the local Mazda dealers won't have a clue on this. Help anyone? Pleaseeeeeeeee? Quote Link to comment Share on other sites More sharing options...
SteveSter Posted January 21, 2009 Report Share Posted January 21, 2009 Engine mounts? Is there also a vibration when your in gear? Quote Link to comment Share on other sites More sharing options...
cuto Posted January 21, 2009 Author Report Share Posted January 21, 2009 Engine mounts? Is there also a vibration when your in gear? Don't think its the mounts Steve, the knock only happens as described, on a cold start i've never heard it. No vibration at all. All i can think about is any belt knocking, as it seems related to heat and cold. Also, is there any belt that only runs when in gear???? Quote Link to comment Share on other sites More sharing options...
cuto Posted February 3, 2009 Author Report Share Posted February 3, 2009 UPDATE: Yesterday i was able to hear the knock again, under the described conditions. As soon as it started i popped the hood and checked it. It seems to come from the SC area....unfortunatelly it only lasted for about 10 secs. I wonder, could it be the SC belt? Or worse...is this a symptom of a failty SC? On a fast search: Steve, it sounds like you posted here http://www.mazdaworld.net/forums/index.php...;p=247275 The only difference is that it never knocks on cold starts or in whatever other conditions, appart the one i described. I guess im screwed... Quote Link to comment Share on other sites More sharing options...
ing-schu@online.no Posted February 3, 2009 Report Share Posted February 3, 2009 Maybe it is your AC compressor clutch? Try to manually engage and disengage it while listening for strange sounds. It should engage with a distinct sound, if it struggles or fails to engage it will make a nasty klicking sound on idle, and more like a concrete power drill if revving the engine. I doubt it comes from your SC. Then I'd rather suspect the timing belt tensioner, but with your low milage I doubt that too. Have you checked your splashshields are not cracked under and around the engine belts area? Quote Link to comment Share on other sites More sharing options...
enginph Posted February 3, 2009 Report Share Posted February 3, 2009 video needed. Quote Link to comment Share on other sites More sharing options...
mts Posted February 3, 2009 Report Share Posted February 3, 2009 Is the frequency of the knock more in the engine rpm (700 at idle) or in the S/C rpm (much higher) I know my S/C used to make god awful sounds before it failed... on starts. BUT, I am not saying yours is going, maybe there is a vacuum leak that seals off when hot. Likely on the ABV system somewhere. Quote Link to comment Share on other sites More sharing options...
cuto Posted February 4, 2009 Author Report Share Posted February 4, 2009 Is the frequency of the knock more in the engine rpm (700 at idle) or in the S/C rpm (much higher) I know my S/C used to make god awful sounds before it failed... on starts. BUT, I am not saying yours is going, maybe there is a vacuum leak that seals off when hot. Likely on the ABV system somewhere. The knock disappears as soon as the engine hits 700 or lower RPM (normal is 500). But what intrigues me is that it only occurs whith the engine still warm on a restart after about half an hour. @Xedos: infact i also noticed in the last few weeks that my AC is not engaging properly. After a long travel the vents just blow air and i have to turn the AC on and off in order to get my windshield deffoged. I was thinking it might be the AC needing a charge. Also, on idle whenever i turned the AC i could feel aa RPM drop (as in most cars). Can't see that now. By the way: i've found YET another good site for parts (had a cabin filter and a air filter deliver in 2 days). They have ALL items needed for service parts. Timing belt kit for 312 Euros! Full fledged kit with all tensors for about 600 Euros. Here: http://www.teilesuche24.de/pkw,mazda,xedos...emensatz,100405 All parts google translated: http://translate.google.pt/translate?u=htt...PT&ie=UTF-8 Jakoparts seems to be another name for Nipparts (part numbers are exactly the same). As im having the car inspected soon, i will be buying all belts (if not needed i'll keep them coz this car dies with me). Quote Link to comment Share on other sites More sharing options...
enginph Posted February 4, 2009 Report Share Posted February 4, 2009 Rpm is 650 IIRC (written under the hood), but never 500 for sure. When AC engages my rpms increase as it should be. If the car doesnt shake and exhaust flow is continuous (listen it), then the knock is not firing related I would say. How about the frequency cuto? Quote Link to comment Share on other sites More sharing options...
cuto Posted February 4, 2009 Author Report Share Posted February 4, 2009 Rpm is 650 IIRC (written under the hood), but never 500 for sure. When AC engages my rpms increase as it should be. If the car doesnt shake and exhaust flow is continuous (listen it), then the knock is not firing related I would say. How about the frequency cuto? I meant to say increase also :>. Now whenever i turn the AC on sometimes it engages and i can see the RPM go up, sometimes it does not. Im pretty sure it is not firing related as the car does not shake at all and all look fine wuth my smoke (almost none...mostlty water vapor in these winter days), As for the frequency, it sounds like a Toc-Toc-Toc every half a second (almost like something is spinnig with a belt and hitting something every rotation). I am sorry i can't get a video coz heck: it is very random and i can't reproduce it whenever i want. Even if i carry a cam, as soon as i got it preped for shooting the knock is gone (the longest i heard it was abou 15 seconds). Also, i never rev the engine when i heart it, did it once or twice and it imeddiately went away. Now i just wait for a stready idle, as soon as it hits those 600 or 700 Rpm's it's gone. Quote Link to comment Share on other sites More sharing options...
enginph Posted February 4, 2009 Report Share Posted February 4, 2009 Anything similar here: http://www.youtube.com/watch?v=xtSeCgQ4GZs Quote Link to comment Share on other sites More sharing options...
SteveSter Posted February 4, 2009 Report Share Posted February 4, 2009 When you turn on the AC the compressor does not always engage, Unless you put it on auto at 65 degrees. Mitchell on Demand says idle should be 700-800 no AC with AC 800-900. If the Idle is too low, then the SC doesnt have enough centrifugal force to spin steadily and rattles a bit. IF you would like to raise your idle adjust the brass colored flathead screw ontop of your throttle body and tell us if it goes away. Quote Link to comment Share on other sites More sharing options...
cuto Posted February 4, 2009 Author Report Share Posted February 4, 2009 Anything similar here: http://www.youtube.com/watch?v=xtSeCgQ4GZs Saint: thanks for the video, the knock is not the same, BUT at second 20 of that video you can hear a background noise not as mettalic as the other (as you aproach the cam). I think it is that one but a bit louder. Also, it comes from that same side of the engine. Quote Link to comment Share on other sites More sharing options...
cuto Posted February 4, 2009 Author Report Share Posted February 4, 2009 When you turn on the AC the compressor does not always engage, Unless you put it on auto at 65 degrees. Mitchell on Demand says idle should be 700-800 no AC with AC 800-900. If the Idle is too low, then the SC doesnt have enough centrifugal force to spin steadily and rattles a bit. IF you would like to raise your idle adjust the brass colored flathead screw ontop of your throttle body and tell us if it goes away. Steve here's the engine idle at warm, you think it's ok? P.S. Here's what the workshop manual says about idle speeds (Autodata confirms it): Load condition Idle speed (rpm)*1 No load 600-700 E/L ON*2 650-750 A/CON 730-830 P/S ON 650-750 *1: Excludes temporary idle speed drop just after the electrical loads are turned on. *2: • Blower motor operating at high speed • Headlight switch turned on • Rear window defroster switch turned on 5. If not as specified with all load conditions, inspect the idle air control valve. If not as specified with anyone of load conditions, check related input SWitches, harnesses and connectors. Quote Link to comment Share on other sites More sharing options...
ing-schu@online.no Posted February 4, 2009 Report Share Posted February 4, 2009 That looks normal, just a tad higher than my 2,5. Just for the record, the reading sub 1000 rpm is: 1st line Zero rpm, 2nd line 500 rpm, 3rd slimmer line (where your needle is, give of take) 750 rpm. Quote Link to comment Share on other sites More sharing options...
enginph Posted February 4, 2009 Report Share Posted February 4, 2009 That looks normal, just a tad higher than my 2,5. Just for the record, the reading sub 1000 rpm is: 1st line Zero rpm, 2nd line 500 rpm, 3rd slimmer line (where your needle is, give of take) 750 rpm. Thats what I thought at first, people think 750 is 500 on the tach. If I sit on a red light or slow down very slowly to a complete stop idle goes down 600-650. That may be because s/c is not overspinning anymore. Steve you may need to put the car to diagnostic mode before playing with the switch. Quote Link to comment Share on other sites More sharing options...
Troutman Posted February 7, 2009 Report Share Posted February 7, 2009 1 member is celebrating his/her birthday today cuto(42) Quote Link to comment Share on other sites More sharing options...
cuto Posted May 13, 2009 Author Report Share Posted May 13, 2009 Update: Got a situation diagonsed (not the problem): The noise ONLY appears when : 1- Engine is still warm enough to start the engine without the revs going up as normal on a cold start. 2-In Park the revs are still above 1.000, no noise. 3-Putting the car on any other gear will drop the revs bellow a certain point and the knock appears. 4-If the car stays in gear for a short period revs go slightly up again and the knock disappears (happens also if i rev the engine in neutral 2 or 3 times). My bet: a belt or a idler that knocks on lower than "desired" revs. Quote Link to comment Share on other sites More sharing options...
enginph Posted May 13, 2009 Report Share Posted May 13, 2009 Anything similar here: http://www.youtube.com/watch?v=xtSeCgQ4GZs Saint: thanks for the video, the knock is not the same, BUT at second 20 of that video you can hear a background noise not as mettalic as the other (as you aproach the cam). I think it is that one but a bit louder. Also, it comes from that same side of the engine. Cuto, I think that noise is gone after I replaced the spark plugs. I will double check today. Quote Link to comment Share on other sites More sharing options...
cuto Posted May 13, 2009 Author Report Share Posted May 13, 2009 Anything similar here: http://www.youtube.com/watch?v=xtSeCgQ4GZs Saint: thanks for the video, the knock is not the same, BUT at second 20 of that video you can hear a background noise not as mettalic as the other (as you aproach the cam). I think it is that one but a bit louder. Also, it comes from that same side of the engine. Cuto, I think that noise is gone after I replaced the spark plugs. I will double check today. Much obliged sir. Quote Link to comment Share on other sites More sharing options...
enginph Posted May 14, 2009 Report Share Posted May 14, 2009 I think its gone. Shot this one today: Is the noise when I first apply throttle normal? Quote Link to comment Share on other sites More sharing options...
Frankzao Posted May 14, 2009 Report Share Posted May 14, 2009 sounds better than mine....why do you not have a CAI? Quote Link to comment Share on other sites More sharing options...
SteveSter Posted May 14, 2009 Report Share Posted May 14, 2009 That sound is the S/C rattling around a bit, mine does the same too. If you put a stethescope on the S/C and do that it sounds like it coming from there. Quote Link to comment Share on other sites More sharing options...
enginph Posted May 14, 2009 Report Share Posted May 14, 2009 That sound is the S/C rattling around a bit, mine does the same too. If you put a stethescope on the S/C and do that it sounds like it coming from there. I didnt hear it before. It also makes a sucking surge when throttle is first applied. I think ABV closes and it pushes all charge to the intake. I dont have a CAI because hmm I didnt get it in OH because of the weather. Now I can get one but its hella expensive from chi. Besides I am skeptical about how good those filters work. Any advantage of it? Quote Link to comment Share on other sites More sharing options...
Frankzao Posted May 14, 2009 Report Share Posted May 14, 2009 Any advantage of it? Wha? You have to ask? Have you not read any of the threads here on it? Yes, definate advantage!!! Faster throttle response, more audible S/C scream, faster excelleration, etc etc.... Quote Link to comment Share on other sites More sharing options...
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