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1G Loud knocking/thudding on acceleration

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Funky Geko

Probationary Member
16
0
Feb 17, 2019
Cleveland, Ohio
So I got the car running, put in the new squirters and new timing belt etc but whenever I first fired it up it had this intermittent knocking sound. Drove it around a bit, went on the highway and off and it got a lot worse after getting off the highway. When I begin to accelerate, it's not very noticeable, but when I push the clutch pedal in to shift it gets REALLY LOUD and then kinda quiet end up when I let the clutch out and into gear, or press the brakes. The wheels are tight (and it makes the sound but not as loud when sitting still), the crank pulley is also new (fluidampr with the longer ARP studs) as well as the tensionor, alternator, power steering pump rebuilt and all new belts. I'be read that the crank pulley could be rubbing or a piston rod bearing may be toast, I took a video that demonstrates the sound. And it's only getting worse, please help!
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i doubt its crankwalk since your car is a 1g.
does the clutch pedal go to the floor on left turns or anything like that?
 
Did you check the thrust bearing clearances when the motor was apart ?
Also is the one bolt for the transmission installed that
goes the opposite way then the other transmission bolts ?
Its near the bottom and is hard to install so people leave it out, pretty sure people call it the crank walk bolt.

And metal shavings are never good. Can u tell if its bearing material ? I'd open up your oil filter and see what's in it.

It's to bad it's not your release bearing
 
i doubt its crankwalk since your car is a 1g.
does the clutch pedal go to the floor on left turns or anything like that?
Nope, the clutch seems to work just fine regardless of which way the wheels are turned. The noise does get very noticeable when I press the clutch in and slowly gets a little quieter once I release the clutch, but it started to just stay the same loudness regardless.
 
Nope, the clutch seems to work just fine regardless of which way the wheels are turned. The noise does get very noticeable when I press the clutch in and slowly gets a little quieter once I release the clutch, but it started to just stay the same loudness regardless.


Does it do it during idle ? Maybe Jack up both wheels and check all your ball joints ,tie rods , wheel bearings , engine mounts , control arm bushings , brakes , exhaust

That noise sounds familiar tho just cant put my ear on it.
my car once made a similar sound but wasn't rpm related but was speed related .

Tire falling off LOL?
 
Last edited:
Is the half shaft tight? Sounds axle related to me.
 
Then why do I hear the sound when the car isn't moving at all?
The sound is only worsened when I press the clutch in, and is still noticeable when I am sitting still out of gear. When I put it into gear and start to drive, it is still making the sound and when I press in the clutch (in the video it's demonstrated) the noise gets a lot worse. It isn't the tires, it isn't the suspension, I know that much. Has anyone had their ENGINE make that sound before? Because it's coming from the engine.
 
I know its hard to do, but I think a better video or sound byte is needed for us to truly hear what you are experiencing. I heard thunking and maybe couldn't hear all of the sound you hear.
 
The sound is only worsened when I press the clutch in, and is still noticeable when I am sitting still out of gear. When I put it into gear and start to drive, it is still making the sound and when I press in the clutch (in the video it's demonstrated) the noise gets a lot worse. It isn't the tires, it isn't the suspension, I know that much. Has anyone had their ENGINE make that sound before? Because it's coming from the engine.
Check all your motor mounts man and your inspection plate although its unlikely since the sound would be there 24/7 .

I agree with 1990 take a video again maybe just put your phone on the ground and coast over it (dont hit it)LOL
 
This is the video I took before the driving vid, you can still hear it (it's kinda erratic, sounds more like a knocking/slight rattle ((it's not the exhaust LOL)) than a thudding in the other vid) but you guys may be onto something it could be axel-related - but why would I still hear it when it isn't in gear/moving if it were a half shaft? When I was tearing apart the timing side there was a f***ton of axel grease under the rubber boot, but the boot looked newer and solid/not torn, but maybe it is bad. The car was built by Buschur years and years ago, the guy I bought it from didn't maintain it much other than some oil changes and tires so maybe it was going bad but I didn't notice when I wrecked my oil pan.

The engine does not have a balance shaft (Buschur deleted) and it has a fluidampr crank pulley, but the old crank pulley looked just like an OEM rubber one (rubber was cracking so I replaced before failure) - I'm starting to think they used the rubber style (maybe it was an ATI or whatever) specifically, idk I don't wanna tear it all apart again I ended up paying my buddy who has more knowledge/experience/time to put it back together for me and he knows what he's doing. He said when he replaced my oil squirters, there was only one crush washer per, so he only used one crush washer per, I'm now worried I hear my squirters rattling in the bottom end but it's too rythymic while driving. And of course Buschur said they "aren't taking in anymore cars" and couldn't even give me a eta on when they will and didn't help much over the phone...
 
Just so you do know, those oil squirters take a washer on top and bottom....They may stay in if torqued to 34 ft/lbs (I thk that's what they are) but are probably leaking a little of their squirt back into the pan.
But bak the noise, just had to relate that. I am at work so I will have to pull the videos up on my phone when I get a chance.
 
Sound could be a pulley going bad. I would put checking them on my list if I was having this problem. Start first with checking all the pulleys for the accessories. If you have AC start with that pulley & the AC pulley clutch assembly.
 
Welp I just checked the timing belt (I checked it before posting, too) and it's loosey goosey and the cam gears are slightly off kilter so it looks like the brand new tensioner went bad somehow. Here's hoping the insides aren't f***ed, I hope I stopped trying to drive it in time. f***ing maddening, especially since I checked it before driving it and after and again and etc. Anyone know of any speed shops/repair shops in Northeast Ohio that'll work on these modified cars?
 
Welp I just checked the timing belt (I checked it before posting, too) and it's loosey goosey and the cam gears are slightly off kilter so it looks like the brand new tensioner went bad somehow. Here's hoping the insides aren't f***ed, I hope I stopped trying to drive it in time. f***ing maddening, especially since I checked it before driving it and after and again and etc. Anyone know of any speed shops/repair shops in Northeast Ohio that'll work on these modified cars?
Can you post a pic? Was the tension set to spec?

Did you rotate the motor over by hand to see if its tightened up ? Obviously stop if there's to much resistance.

Does it run fine ?

Edit : sorry didnt see your other video , that's definitely not a nice sound to hear
 
Can you post a pic? Was the tension set to spec?

Did you rotate the motor over by hand to see if its tightened up ? Obviously stop if there's to much resistance.

Does it run fine ?

Edit : sorry didnt see your other video , that's definitely not a nice sound to hear
I can pluck it, it's sagging, and I don't know if the tension was set to spec I had my friend do it for me - how is that spec determined? From what I know, he lined up all the marks except for the oil sprocket or something, and once he pulled the pin on the tensioner it lined up the final mark and he rotated it many, many times and the marks lined back up after like a dozen full rotations. That knocking sound began to get worse and worse as I drove it (specifically after taking it on the highway for the first time since putting it back together) and so I got it towed and after getting it home I checked the belt and it's loose enough to move like an inch up and down between the cam gears, pretty sure that's too loose LOL I can post some pics tomorrow.

I appreciate all the feedback, what I really need to know now is any repair shops in Ohio other than Buschur who would take this thing in to fix?
 
Maybe the pulley just loosened up, pull the front cover and get a good look before paying so called "dsm mechanics" (Buschur excluded of course). I don't trust any shops with mine.
 
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third picture from the top.

This is s critical step when doing a timing belt job you measure the protrusion and it must be with in 3.8mm-4.5mm.

**I may be wrong but the tensioner pulleys 2 dots have to be around 11 o'clock ** on the tensioner arm.

Also I dont know what you mean with the oil pump sprocket I've always lined up the timing Mark's and put the belt on starting at the cams using zip ties (2 wrenches needed to line up cams if I remember due to the valve springs)

There's a whole bunch of info on this I'd suggest getting a copy or download of the 1g factory service manual.

Tear down the timing side and post pictures I doubt your tensioner failed if it was brand new . Its most likely sticking out to much and cant adjust tension anymore .

Pics do wonders
 
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