[help] Gearbox problem (edit: seems to be engine pinging)

[aznalex]

[history]
hey guys, had my car for about a month now..
clutch and gears were perfect when i got it
everything is stock, the only modification is removal of the resonator while keeping the stock airbox in.

[problem]
whenever i shift into low gear and accelerate to medium, theres this loud rattling noise in the engine bay and it sounds like some piece of metal is going to fall/snap off.
as an example, i put the gear in 4th while going at 40kms and just accelerate half way (foot pedal half way) and this rattling noise will start to go off.

[question]
has anyone had a problem with this before or know what could possibly be wrong with my car? i only got it a month ago and this has come up.. a very big disappointment i am facing.

thanks in advance to whoever replies!

[OMG.JAI xD]

Good thing you highlighted "4th gear" and "40km/h"

Blind shot in the dark.

You most probably have a bad batch of fuel or blocked filter. or just not using 95 octane.
Its a phenomenon called "pinging".
Its the point where fuel is incorrectly combusted in the engine, which in turns, tries to turn your crank the opposite way.


Could be something else though. Im just pointing out the most common thing.

40km/h in 4th gear is abit too much load. Id try downshifting to 3rd if i was going that slow.

[aznalex]

i think my fuel filter is okay, im getting around 500kms per tank of fuel with like 2-3 liters remaining.
i always fill up with shell unleaded, never any of that ethanol stuff.

but i used the 40km in 4th gear as an example.

i also was in third gear and had the foot pedal depressed about 80% going around 80-100 i cant really remember. but i heard the rattling noise there too.

i think its when i put a considerable amount of load on the gears is when it starts to rattle.

[bennjamin]

Sounds engine running condition rather than gearbox

get a service

replace spark plugs , engine oil/filter , fuel filter air filter adjust the timing if the distributor with a timing light/ gun. Run some 95 or 98 octane fuel see if that rectifies the issue.
Also try not to overload your engine try to keep in a lower gear for alittle longer. You are lugging the engine and possibly damaging it by apply too much load at thenwring speed/gradient for the gear selected

[aznalex]

[info]
ive driven like this since i first started which is about a month..
but ive checked the recommended shift points from the owners manual and they are:
[1st 0-16km] (i usually shift at 15-20km)
[2nd 16-32km] (usually shift at 40km)
[3rd 32-72km] (usually shift at 60km)
[4th 72-88km] (coast on this gear from 60km and above)
[5th 88km+] (sometimes use it on the short highway to uni wen im going 100km)

[question] - two
if anyone reads this, is there anything wrong with my shifting??
since this is an old car, must i really stick to the recommended shift pattern outlined by honda?

[random]
i remember my friend just said "i shift whenever i feel like"
so i kinda made my own pattern where id shift in 20's km..

[typical driving pattern]
first gear then shift at 20km
second gear then shift at 40km
third gear then shift at 60km
and id usually stay in fourth gear from 60 ~ 100 since i dont keep my speed at 100 for that long

[OMG.JAI xD]

Remember that hondas dont have alot of torque down low.

[aznalex]

Remember that hondas dont have alot of torque down low.

lol sorry, im not sure how to interpret that.

low torque kills the engine? :s

[OMG.JAI xD]

Sorry maybe i should elaborate.

Minimal torque down low means you have to apply more throttle to get it going.
If you stayed in the low rev range at a high gear. You are applying excessive load to the engine for too long.

Just remember that just because your revs are lower, does not mean youre more fuel efficient.
10% load at 4000 rpm can be more efficient than 100% load at 2000rpm.

By load. I mean your throttle position. 10% = cruising. 100% = WOT (wide open throttle).
Let the engine rev abit more. Itll prolong your engine life aswell.

[vtecing]

always wonderd what WOT means. thanks man!

[aznalex]

Sorry maybe i should elaborate.

Minimal torque down low means you have to apply more throttle to get it going.
If you stayed in the low rev range at a high gear. You are applying excessive load to the engine for too long.

Just remember that just because your revs are lower, does not mean youre more fuel efficient.
10% load at 4000 rpm can be more efficient than 100% load at 2000rpm.

By load. I mean your throttle position. 10% = cruising. 100% = WOT (wide open throttle).
Let the engine rev abit more. Itll prolong your engine life aswell.

ooh, okay, thanks for that, i always thought revving higher for a prolonged time wears the engine down..
i guess i will stick to the recommended shift positions outlined in the honda owners manual

in my last drive i closely stuck to the recommended shift points and found the rattle noise is much less however still present.

[question] (really need an answer for these!)
is there a possibility that the noise will completely leave after correcting my driving style?
or do i have to get this rattling noise checked out by a mechanic?

since i bought this car second hand, so im not sure if this issue could have come about from the previous owner..

[xntrik]

is this noise loud enough to be recorded?
could just be a loose screw, coins? (stating the obvious just in case)


vibrations throughout the car can make alot of things loose.
and some noise only come out when certain vibration occurs.

[aznalex]

yeh its loud enough to be recorded if i cruise on a high gear then try to "WOT" it, i assumed it was some loose screw inside the engine bay that needs to be tightened but wasnt too sure.

example to the above: cruising in 4th @ 60km, then WOT, "it" will start to rattle out loud

thought maybe to do something with the clutch, since im new to manual and not shifting like a pro.