Humming after warmup (infamous W.I.P.)

coloradotuner · Jan 21, 2015

Hello all, Just the other day after driving home from school this weird hum from the front drivers side belt area started.from what iv read so far, hums are very hard to pinpoint on these cars, and the obvious solution isn't always the correct one. I recently had some of the front suspension components redone: balljoints, steering dampeners, control arms, and I just got a complete rebuild of the tranny and the t-case and a brand new clutch (went with oem) as well as new oil for the rear diff.

the story
I went to start off from a red light and I revved to about 2,500 rpm to release from 1st, then which bogged the car so bad it nearly died for a second and the check engine light came on then 2 seconds later went off and the car had power again, then the infamous hum started. This happened again yesterday while out running to the grocery store except this time I was downshifting from 3rd gear to 2nd gear I revved to about 4k rpms and the car bogged and the check engine light came on and then immeadiatly turned off (detonation?).

after doing research on my symptoms/ getting to know my GSX
Some concerns I have is that I have not properly broken in the clutch and somehow messed it up, or the t- case is leaking (which isn't likely since it should be brand new) or maybe the belts are too loose/too tight, or the timing belt skipped a tooth, the previous owner said it would need a timing belt job around 150k when I bought it off him and it only has 122k on it currently. My car's engine constantly seeps coolent all over the block and seeps/drips oil (TWO DRIPS A DAY literally... FML), the seepage has been seen by many mechanics up here in the valley all which have said its okay for now and completely normal for aluminium blocks to do this. also, If i leave the car sitting for 3 days the battery will die. The car seems to make a gnarly grinding sound that only lasts a half a second when cold started in the mornings which sounds like its coming from the lower portion of the car (crank?), Is my daily driver all stock dsm crankwalking!!!!!! ???

Every month it seems to be a new PROBLEM and now I'm just constantly paranoid while driving it.(does it ever end?) Which is why I'm not sure if I broke the clutch in properly/ broke somthing, question, What RPM should Ibe launching the car from during quiet driving times , I usually rev to about 2,500k which usually nearly bogs the car, I started revving to 3k today for daily driving and the car seems to like that better and doesnt bog.

symptoms include
The hum is not present during initial warm up. even if I sitthere and rev the car to 4krpms no hum occurs.
The hum starts after driving it for a couple short minutes
it seems to be coming from the drivers side lower-midend of the car. (pullys belts hopefully)
it gets louder when the clutch is pressed down (Sitting still)
it gets even louder when taking a sharp left turn (oh shit)
The hum seems to mimic the idle input

sorry for the long read, but i wanted to be very clear in my synopsis of this problem,because hums are typically hard to locate.
Please help, and please be kind, still learning here, any insightful knowledge is welcome.

2gmitsueclipse · Jan 21, 2015

You have a lot here. To start off, what all was replaced when the clutch and trans-axle were replaced?

Was the flywheel replaced or resurfaced?
Was the disk and pressure plate replaced with new units?
Was the throw-out bearing replaced with an OEM unit?
Was the clutch fork and fulcrum replaced?
Was the clutch adjusted using the procedure below?

You must be logged in to view this image or video.

Now on to the other issue. Don't jump right to crank walk!!!!!!I would check the condition of the crank pulley. Is the rubber cracked or missing? Is it separating? If not, check out the accessory belts for wear. If noise still persists, remove the timing covers to expose the timing components. Try to get all timing marks aligned to see if you are "in-time". Check for obvious signs of a problem at this point such as broken or worn parts and fluid leaks. If nothing is obvious, keep the timing covers off, install crank pulley and alternator belt. Have someone else start the car while you watch/listen to pin-point where the noise is coming from.

One other note: check to see if the starter is bolted on tightly. Also complete a BLT to address the bogging issue.

coloradotuner · Jan 21, 2015

2gmitsueclipse said:
check out the accessory belts for wear.

They look fine

2gmitsueclipse said:
Is the rubber cracked or missing? Is it separating?

no cracks or separation, while at idle the pully will move slightly back and forth suggesting some play in my pullys but the belts are all tight.

2gmitsueclipse said:
Try to get all timing marks aligned to see if you are "in-time"

how do you do this?

2gmitsueclipse said:
starter is bolted on tightly. Also complete a BLT to address the bogging issue.

where is the starter, also I don't have any boost leaks just a slight leak near the 2g BOV

coloradotuner · Jan 21, 2015

2gmitsueclipse said:
Was the flywheel replaced or resurfaced?
Was the disk and pressure plate replaced with new units?
Was the throw-out bearing replaced with an OEM unit?
Was the clutch fork and fulcrum replaced?
Was the clutch adjusted using the procedure below?

Yes to all except the last, not sure, I have seen that vid before and I adjusted the clutch like that before the rebuild, the clutch seems to be adjusted okay but I will double check this weekend when I get a chance.

What happens to the clutch if to much clutch is used and not enough throttle input is used? Will it wear away faster? or will it mess up some bearings inside the tranny/ clutch and start humming?. I think the key here is that the drive train is basically brand new but bolted up to a seeping motor with possibly loose belts. like I said previously I have been basically baby- driving the car since the rebuild , no hard pulls, basically bogging it down around town stop to stop

2gmitsueclipse · Jan 21, 2015

http://vfaq.com/mods/timingbelt-2G.html

2gmitsueclipse · Jan 21, 2015

Starter is under the intake manifold. It is accessible underneath with some creativity, or by removing upper intake pipe and battery/tray.

CaitSith · Jan 21, 2015

2gmitsuseclipse, you're awesome! Crankwalk is very rare, so definitely don't think that’s the issue right off( I’ve made the same mistake. Like you said in the original post, thinking it's something it's not). It sounds like there is an issue with something that happened when replaced your clutch. There is alot that has to come out for a clutch replacement and alot of errors could occur with a shop that’s not use to dealing with DSMs or turbo cars. Consider looking at a clutch replacement video and backing through the assembly, torque specs and all.

rough · Jan 21, 2015

The sound you hear on startup is the starter sticking, not retracting the starting arm quick enough.

2gmitsueclipse · Jan 21, 2015

You did not mention anything about the flywheel. If reused, was it resurfaced? If resurfaced, was it stepped? Stepping is important as it changes the engagement position of the pressure plate and clutch disk. If this was done, you most likely would need to add a shim to the fulcrum to account for the change. The pedal adjustment will make a HUGE difference when done properly.

coloradotuner · Feb 14, 2015

I did the proper clutch adjustment just like in the video, the clutch feels like butter. I got a chance to put around town doing stop and go traffic, the hum is still coming from the timing belt area, from a dead stop I was revving to 3k r.p.m.s while simultaneously letting out the clutch, the car does seem to have a loss of power when starting out but while driving the turbo spools up just fine and the power is there, also I noticed high idle while sitting at stop lights, normal idle for my car sits right under 1k rpms, but it would slowly start to creep up to 1350 rpms.

update: I had a friend look at it and he thinks the idler pulley, and recommended a timing belt job. I am taking the car into a local repair shop monday to get a second look/ opinion.

wrencher · Feb 14, 2015

coloradotuner said:
What RPM should Ibe launching the car from during quiet driving times , I usually rev to about 2,500k which usually nearly bogs the car, I started revving to 3k today for daily driving and the car seems to like that better and doesnt bog.

Just curious....You rev the car to 2.5-3k clutch release for daily driving to get the car going from a stop?

mercaholik · Feb 16, 2015

Is the hum engine speed related or road speed related?

catomlinson42 · Feb 18, 2015

Hope shop can fix ur problem man but on a side not there is no need to rev up to 2500 when driving normally around u should be smoothly engading/disengadging while gassing it correspondingly no need to rev up then start to release ur gonna burn out that oe clutch way to quick

coloradotuner · Feb 18, 2015

wrencher said:
Just curious....You rev the car to 2.5-3k clutch release for daily driving to get the car going from a stop?

yes I have been.. I thought this would break in the clutch

coloradotuner · Feb 18, 2015

mercaholik said:
Is the hum engine speed related or road speed related?

engine speed related, I just got done picking up a friend from the river, symptoms are still the same , no hum whatsoever while warm up even if I rev it up. Pulling away from 1st gear the car starts to pull normally then a loud hum almost (like the sound of those electric Little-Tike atv's/car thingys for 5 year olds),and a noticeable loss of power, the hum persists while driving, but gets quiet, then loud then I take a turn and it gets really loud. Its weird that the noise isn't present during warm-up..

coloradotuner · Feb 18, 2015

catomlinson42 said:
Hope shop can fix ur problem man but on a side not there is no need to rev up to 2500 when driving normally around u should be smoothly engading/disengadging while gassing it correspondingly no need to rev up then start to release ur gonna burn out that oe clutch way to quick

okay I will work on being smoother with the engaging and disengaging, thanks for the thought I will keep that in mind.

o0GuitarKid0o · Feb 18, 2015

Take off the alt belt and ac belt and pull the outside of your harmonic balancer(crank pulley) if you can wiggle it maybe the rubber seperated and is rubbing your timing cover enough to make a hum which will turn into a grinding sound, I went through this and thought it was my water pump or something but was that good ol crank pully

steelcurtaindsm · Feb 18, 2015

probably best to go ahead and do timing belt job .Did previous owner give any documentation on belt change? I always do one when i get a used car , just so i know how many miles are really on it. Just an expense i plan on .good luck keep us posted if you figure it out.

The Top DSM Community on the Web

Humming after warmup (infamous W.I.P.)

coloradotuner

2gmitsueclipse

coloradotuner

coloradotuner

2gmitsueclipse

2gmitsueclipse

CaitSith

rough

2gmitsueclipse

coloradotuner

wrencher

mercaholik

catomlinson42

coloradotuner

coloradotuner

coloradotuner

o0GuitarKid0o

steelcurtaindsm

Similar threads

Latest posts

Build Thread Updates

Vendor Updates

Latest Classifieds