View Full Version : Electric like buzzing in 4th gear O/D?
Aströn Boy
18-02-2008, 11:24 AM
so yeah, I seldom take the thing into OD, but was driving the freeway doing 110, so opened her up abit.
Nothing on the way out, but with the return trip the car began making a loud buzzing sound, kinda like the alternator sound you get thru your speakers when there's no filter.
Noticed it this morning as I had forgotten to turn 4th gear off when driving, it would kinda slug into 4th and like clockwork begin the buzz, the faster you went the louder it became.
any clue? kinda sounded like a bad regulator if you've ever heard cheap chinese electronics in action.
BTW, it almost sounds under the dash where the AC intake is, but that thing doesnt work, so it isn't that.... could it be the TCU?:nuts:
Gerard
18-02-2008, 11:25 AM
where is the noise coming from?
Aströn Boy
18-02-2008, 11:25 AM
where is the noise coming from?
edited with that, forgot to include :D
also, by by the way, lol, this is my carby wagon, no ecu, just a horrible tcu.
no stereo currently installed, and the tcu is in plain site
Also turned off the fans had windows up, and atm the engine purrs like a kitten. no electrical problems.... that i'm aware of.
magna buff
18-02-2008, 01:32 PM
first disconnect the battery and reset the tcu
then
have a passenger
drive car o/d off below 70 k
passenger put their hand on the TCU and feel for the buzz vibration
go above 70 k o/d on
passenger put their hand on the TCU and feel for the buzz vibration
inside the TCU just printed circuits the metal screws may be loose/plating
the o/d button on the shift is only plastic and small metal contact
no aircon /no radio/ no other cause for a buzz
did someone drop screws off the metal frame of radio/ cig lighter/
plastics of the console stuff in the fresh air intake ?
the fuel relay should click
I would take the cover plate off the overdrive on the auto and check the unit
for anything broken or worn friction disks just to eliminate an overdrive fault
Aströn Boy
18-02-2008, 03:26 PM
buzz happens regardless of speed can be doing over or under 70, have even done 110 in 3rd gear and no buzz.
if there were screws or anything loose, then it would sound all the time and not just when 4th gear is engaged.
As it happens the battery was disconnected after my drive yesterday when i was reinstalling my pwr mirrors (yes I'm that cautious:nuts: )
and today it still made the noise.
i spose its not the greatest concern, i mean i barely engage 4th, but still its an oddity.
will see if i can get someone to put there head under the dash and cofirm if it is the tcu, coz atm its speculation.
coldamus
18-02-2008, 05:20 PM
I know this doesn't fit with your observation that it only happens in overdrive However two of my 1st Gens have made a similar noise. It comes from the rod/s that operate the heater control.
If you have the heater control lever all the way over to the left (cold), it vibrates. If you move it just a smidgen towards the right, it stops. I think this is because the rod is in a loose state in its default position. Moving it places a small amount of tension on it and stops it vibrating.
Try it just in case. Mine only vibrates over a certain range of speeds. Perhaps yours only hits the right vibration frequency when it is in overdrive.
Aströn Boy
18-02-2008, 05:59 PM
I know this doesn't fit with your observation that it only happens in overdrive However two of my 1st Gens have made a similar noise. It comes from the rod/s that operate the heater control.
If you have the heater control lever all the way over to the left (cold), it vibrates. If you move it just a smidgen towards the right, it stops. I think this is because the rod is in a loose state in its default position. Moving it places a small amount of tension on it and stops it vibrating.
Try it just in case. Mine only vibrates over a certain range of speeds. Perhaps yours only hits the right vibration frequency when it is in overdrive.
hmmmm.
well, it's worth a try, i'll do it tomorrow morn.
mm, hang on tho, its electric and the sound and pitch increases with rpm,
Aströn Boy
18-02-2008, 07:38 PM
Turn your stereo off completely, you'll find the whine is from your speakers... It's called alternator noise.
umm
might wanna read all my posts. you'll find my stereo is turned well off ;)
magna buff
18-02-2008, 08:48 PM
do you have a TCU to swap from your other TPs
much quicker to resolve your problem
Gemini
18-02-2008, 08:50 PM
Could it be a dogey tacho cable or something ?
Aströn Boy
19-02-2008, 04:25 AM
Could it be a dogey tacho cable or something ?
speedo cable? and no, wouldnt make sense to only happen in 4th, and sound electrical.
I think I do have a tcu under the house, dunno it's condition tho. Might crack it open see if there are any leaking caps ad such, if not shove it in and see what happens.
Gemini
19-02-2008, 06:53 AM
Solution: dont go into overdrift :P jk
I hope you get it sorted out. I hate annoying things on cars. I have a huge flat spot on one of my tires ( was taken off a commodore rim :roll: ) and the thump drives me insane. At freeway speeds it sounds like a supercharger wine lol
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