Hi all ,

recently my car is acting pretty weird , as weekly I will do some runs around my area , I Realize something wrong with the gearbox (possible) ?

first to 4th gear was ok , on 4th gear at 6100rpm @ appox 165km/h shift to 5th gear , rpm drop to 4.5k rpm with speed reducing instead of holding on or continue to climb

other thing is 0-3.3k rpm car was lively but above 3.3k car seems sorts of 'unwilling' to climb

what could be the cause ? Engine mileage 96k

 

My goodness, you like to rev that engine! Been awhile since I had my GD3, but wasn't the redline 6500 rpm? If you're regularly flirting with that redline.....

At 96K, you should be thinking about replacing the plugs (recommended at 100K) if you haven't done so yet, and a valve lash adjustment if you haven't done that yet.

The common thinking on these engines is that the valve lash should be done every 60K because the engine design pounds shut the exhaust valves and pounds open the intake valves over time. Net effect: the engine doesn't breathe as well. When I did my first valve adjustment on my GD3, felt like I gained an extra gear, the power distribution was that much better. Just a thought.

 

Hi ,

yup weekly high rev of my car actually , already change plugs and stuff already

i think for JDM GD3 Rev cut is around 6300rpm ...

valve be adjustment might have an effect on the power ?

 

At over 100 mph in 4th you wonder why it doesn't want to accelerate when you select 5th? Only on a track day would I get the chance to try that, and see what mine does!

 

It seems my 5th gear is 'weak' , drop rpm and drop speed too

I not sure if is the final drive thingy ...

 

Not a transmission problem, not clutch slippage, but a loss of engine power


Check engine light? Fault codes?

Exhaust restriction? (clogged cat), or intake restriction? (clogged air filter or....I've seen rodents store food inside the breather tubing and chambers causing severe performance problems)

 

Yes, valve adjustment will have an effect on the power stroke. While both the intake and exhaust clearances are important, I believe the exhaust clearance is the one which tends to cause the most problems, at least on this engine.

If the exhaust valves are tight, the engine will not be able to vent exhaust gas as well as it normally would. That means you're always leaving some exhaust gas behind, which in turn affects the intake gas & power stroke.

I think this would be especially noticeable at higher rpm, and if you're regularly running at redline, it would be at its most severe, as the engine can't catch up with the increased demands from the throttle because it can never vent all the exhaust gas being produced.

If memory serves, the spec for the valves is:

Intake - .006 - .007 inches

Exhaust - .010 - .012 inches

If you haven't done the valve lash adjust yet, it's time. Give it a try and get back to us.

 

No CEL , already plug in ECU no fault codes coming out

exhaust and intake working fine ..

could it it be injectors dirty ?

 

okay thanks shall do a valve clearance and see