Loud Knocking

[92whitetsi]

today i hacked my air can and in the process of putting it back together i forgot to put the electrical connector back in the BCS. i went for about a 20 minute drive came back home and checked the engine over and realized the connector wasn't plugged in. So i plugged it in and went for another drive and came back and right when i stopped to let the car cool down i hear this loud knock. i jumped out to see if i could see anything wrong....just could tell it was from near the valve cover then i quickly shut it off...any ideas of what the prob is?

 

[greyforestgst]

so the noise occured at idle?

 

[92whitetsi]

yeah it seemed to start once i got back home

 

[Eclipsor16G]

Is it a rythmic tick-tick-tick-tick-tick? If so, then it's probably lifter tick, which is very common on DSMs.

Chris

 

[92whitetsi]

this is quite audible and it can be heard from inside my house. what else could it be besides lifter tick

 

[laserman90]

could be a rod knocking

 

[92whitetsi]

what are my options to idenify the problem and fix it?

 

[nutshot]

Options:
1.)check oil level
2.)Run car at idle and listen for intensity. If the rod is knocking, yer engine will shake pretty hard and the knocking will sound very evil.
3.)Check yer plugs, many cars start to run poorly, often when introduced to mass quantities of air for the first time. If there is a large carbon build-up on the plug, your car may be dieseling.
4.)Curl into a ball and pray.

 

[92whitetsi]

here is the scenario now. checked the car thoroghly over today and
found nothing sticking out at me that could be wrong. so i decided i'd
reset my ecu just for the heck of it. Well right after i started it after
that it ran fine...drove it for a while...seemed good. then after about a
20 minute drive i came home again and it started knocking right when it
started idling. I will only happen if the RPMs are below 1k. If i hold the
gas at 1k or above everything seems smooth. Anything you can think of to
cause this. Would the ecu cause anything like this from retarding timing.
just curious because i used 89 octane gas. but, i always used 89 on my
usspec motor so i don't understand why the jdm would be different.

 

[dawgedeclipse]

Originally posted by 92whitetsi
here is the scenario now. checked the car thoroghly over today and
found nothing sticking out at me that could be wrong. so i decided i'd
reset my ecu just for the heck of it. Well right after i started it after
that it ran fine...drove it for a while...seemed good. then after about a
20 minute drive i came home again and it started knocking right when it
started idling. I will only happen if the RPMs are below 1k. If i hold the
gas at 1k or above everything seems smooth. Anything you can think of to
cause this. Would the ecu cause anything like this from retarding timing.
just curious because i used 89 octane gas. but, i always used 89 on my
usspec motor so i don't understand why the jdm would be different.

hmm, read your fuel gauge, says to use premium ONLY, this is prolly what is causing the knock, just my .02, i also filled it up with just 89 cause i had only had the car for 20 minutes and it didnt even phase me at the time, but now its premium.

 

[92whitetsi]

i used 89 because thats all there is in my town. Anyway i have figured out that the knock only occurs at slow idle like below 1000 rpm. If i let the rpm drop below 1k then it knocks and starts to shudder like it wants to die. above 1k it runs just fine

 

[boosted_91_tsi]

I am having the same problem in my 91 TSi. I dont want to drive it in case it may be a rod, i would rather replace them now than wait for it to go. Going to check all over tomm, so i will post what i find.

thanx for the space....Dan

 

[boosted_91_tsi]

by the way, i am running 93 octane, so i dont think the fuel is the problem....i wish thats all it were though.

 

[dawgedeclipse]

you could have a vac leak or you could be running too lean

 

[boosted_91_tsi]

Would a vac leak cause it to knock though...it sound like something bumping not just a hesitation type knock. kinda sounds like a pulley is off balance or something, i dunno but i will kno later today. and i will double check for vac. leaks

 

[boostin97talon]

If it's a deep, rythmic knocking sound, it's probably a rod. It only does it at >1000 rpm's because that's when your oil pressure is the lowest, and the problem is in it's early stages. Using a thicker oil may lessen the knock, but that is definetly not a fix. If you care much about your car, get it to a shop asap to let them determine what it is for sure. I said 'if you care about your car' because I had an old Dodge truck years back that had a rod knock at idle, and I drove that thing for almost a year like that. I did not care about that truck.

 

[boosted_91_tsi]

YAAAAA!!! All fixed.. Mine was a pulley comming apart. At low rpm it would kinda wobble and hit the lower timing belt guard, but at higher rpm's it was able to balance itself out. After we got it off it fell apart. Lucky we had an old spare in the garage, so 10 min later it was running perfect. ( its good to have a personal mitsubishi tech, haha) However i am going to replace all the belts next week and a new pulley just to be safe. Hope your problem is as simple as that. Good Luck........

I wouldnt drive it till its fixed though, could make a BIG mess.

 

[92whitetsi]

i found a vacuum line disconnected today but it still knocks at low idle

 

[92whitetsi]

is there any chance my cars BISS needs to be reset because of my test pipe and Air Can Hack and Filter

 

[awd4g63]

Hey 92... this may sound strange (and it may also be a pain to do), but check your flywheel. Some of the bolts in my flywheel were coming loose and causing it to shake at low RPMs. As it got worse, it started to do it as I shifted gears. You can get under your car with a crowbar, take off any shields, and check the flywheel for play. Not an exensive problem at all, but I had to drop the transmission and re-torque all the bolts. Anyway, the noise was a knocking, just like a rod knocking; so I would check that for play and see how it goes.

 

[XCTeam91]

I had the same problem and still do i replaced my timing belt and the waterpump. And had it timed at the dealer ship and i have deen hearin the loud knocking sound . I have spent so much mmoney haveing them do stuff. I have checked my oil and it is fine i change it every 3000 miles. What else could it be.

 

[NJdsmguru]

I'm having the same problem. Turns out to be that my flwheel was loose. I can turn it side to side rotations w/o the crank turning so I guess the bolt holes are slotted now. And even worse than that I had 5 flwheels bols in there one was broken okk in crank and all other were cross threaded. The mechanic who did the clutch before me really screwed up. Now I will have to install new crank ..flywheel and hardware.