Great response with 100 octane, need tuneing??

[MIRZ]

i have Honda Accord CD5 1994~95.

According to book it should use 95 octane (regular unleaded) fuel.

yesterday i tried Shell 100 Octane fuel in it (full tank with only 100 octane).

response on both accelration and decelration is too good now. i am feeling like driving a totaly new car.

what does this mean? its engine should be tuned for 95 octane and should give similar response on 95 octane.

someone told me 100 octance can damage engine fuel sensors, so dont try it again.

do i need to take my car for engine re-tuning? its 211,000 kms driven and bought it when it was 82,000 kms. i never took it for tuning.

what would you suggest? how much Honda charge for tuning (approx $$)

thanks in advance.

[teaseR]

tuning or servicing?

[aaronng]

Why don't you just use 98 octane instead? The seals in the CD accord might not be ethanol-resistant.

[destrukshn]

please tell me you've serviced it in the past 130,000kms.
=/

[MIRZ]

oh yeah, forgot to mention this 100 octane has 5% ethanol in it (thanks aaronng).

i will try 98 octane next time once tank would be close to end (dont wanna make my own blend with half of 100 and half of 98 octane).

and i am using NGK iridium spark plugs for last 6 months (claims to last for more than 2 years or 50,000 kms)

my understanding was that these new cars dont realy need tuning. so not sure and bit confused about this re-tuning thing.

is it true to re-tune new cars? how often it should be done.

[MIRZ]

on 10,000 kms took it for cambelt replacement service and after that took it for service at 120,000 kms.

since then i am replacing engine oil and filter on every 5,000 kms, and transmission oil on every 20,000 kms. spark plugs on every 20,000 kms. but this time got NGK iridium, so planning to run it on for 50,000 kms on them.

if you are asking service form dealer, noop.

[aaronng]

As long as you changed the engine oil and other fluids, it's fine.

But in terms of tuning, all you do is maintenance items like fluids, belt, dizzy. The engine electronics will take care of the rest.

[EuroDude]

You should use 98RON instead, 100RON (ethanol) is actually less fuel efficient, plus it may play silly buggers with your engine/fuel seals

[EuroDude]

EDIT: i should add that the better performance you are feeling from the 100 RON fuel may just be a perception thing, there might not actually be any benefit.

True. Although 98/100RON has fuel additives that may have cleaned the fuel injectors etc..

[aaronng]

the 5% ethanol should be perfectly safe, my understanding is that you need a much higher concentration before it starts to be a problem. And its a problem only on some cars.

Also, regular unleaded is 91 RON, not 95. Premium is 95.

Dont see how the 100 RON will damage any sensors either. The oxygen sensor will have issues with leaded fuels but i'm not aware of any issues posed by any unleaded fuels.


Honda's statement is that only cars from 2003 onwards are safe to use ethanol in their fuel.

[EuroDude]

Honda's statement is that only cars from 2003 onwards are safe to use ethanol in their fuel.


Very true ~

All Honda vehicles should use the fuel recommended in the Owner's Manual. The following models will operate satisfactorily on E10: Insight - 2004 onwards; Civic range (including Civic Hybrid) - 2004 onwards; S2000 - 2004 onwards; CRV - 2003 onwards; MD-X - 2003 onwards; Accord & Accord Euro - 2003 onwards. Honda does not recommend E10 for other vehicle models because there may be drivability issues.
Source: http://www.abc.net.au/brisbane/stories/s1466787.htm

[MIRZ]

True. Although 98/100RON has fuel additives that may have cleaned the fuel injectors etc..

so this means fuel injectors should be cleaned too after some sort of regular intervals?

[MIRZ]

You cant tune the stock ECU at all...its just a matter of keeping the car serviced. That includes things like checking the tappets are in spec, not just changing fluids.

EDIT: i should add that the better performance you are feeling from the 100 RON fuel may just be a perception thing, there might not actually be any benefit.

there is definately a big difference in response. not just my own perception. i can understand that difference.

i never touched tappets, and my understanding is that loose tapets gives you a specific sound to tell you that they are loose, specialy at the time when you accelrate and then release it suddenly, you can hear shrilling or (cant rrealy explain tappet sound)

and tappets cannot be tightened by themselves :)

is there any other way to findout if tappets are loose, thanks.

[aaronng]

there is definately a big difference in response. not just my own perception. i can understand that difference.

i never touched tappets, and my understanding is that loose tapets gives you a specific sound to tell you that they are loose, specialy at the time when you accelrate and then release it suddenly, you can hear shrilling or (cant rrealy explain tappet sound)

and tappets cannot be tightened by themselves :)

is there any other way to findout if tappets are loose, thanks.

It's called a valve clearance check in Honda naming terms. If the clearance is too much, your engine starts sounding like a diesel. And when you adjust them, it is to get the gap between the valve and the rocker back within spec. So yes, you can and must adjust them if they are not within spec.

[MIRZ]

thanks aaronng, any idea how much it would cost.

should i go to honda or any auto mechanic can do this???

[aaronng]

Go to a mechanic that you trust. Not sure on price. Dealers usually charge $500 or so for the service including a valve clearance check. Ask the other Melb Ozhonda peeps on where they go to do their valve clearance check & adjustment.

[EuroDude]

It takes max 1 hour labour so expect about a $100 charge if a mech does it (should take a pro about 30 minutes, or 1-2 hours for a n00b).
A Honda dealer would charge a considerable amount more, but you can pretty much guarantee the job will be done properly.

Or you can do it yourself if you are game. Its not that hard to do once you know how. My mech cheated and stuffed the clearances up (he only rotated the engine once 360 degrees), so I had to fix it up myself lol.

Buy a spacer gauge set for ~$15 and some gasket sealant and an socket extension at an autoshop, find out which size spacer to use for your engine model, remove the top engine cover, rotate the engine to TDC, check and adjust four tappets, then rotate the engine 180 degrees and check the next four, rotate another 180 and adjust, then once more. Then apply new sealant around the sharp curves of the rocker cover and put it back on.

Buy a Haynes workshop manual for your car model and follow the instructions ftw.


ps. Found a DIY by ECU-MAN: http://www.ozhonda.com/forum/showthread.php?t=15443&highlight=tappet

[MIRZ]

thanks aaronng and eurodude.

i have Haynes workshop manual for my car, and DIY from ECU-MAN seems good too.

would better try it first by myself, hopefuly things will go fine otherwise Honda is always there to fix it , LOL.

[aaronng]

It takes max 1 hour labour so expect about a $100 charge (should take a pro about 30 minutes, or 1-2 hours for a n00b).


You need to let the engine totally cool down before you inspect. So that adds 3-4 hours of cooling down time.

[EuroDude]

Yeh give it a try. Read both guides to get the jist of it all.

If you take your time and triple checked the clearances before and after the adjustment, and make sure the bolts are tight enough using the correct torque, It should be fine :thumbsup:

[EuroDude]

You need to let the engine totally cool down before you inspect. So that adds 3-4 hours of cooling down time.

Yeh thats another thing my mech didnt do, he worked on the tappets while the engine was warm, but he said that he compensated the heat by using a smaller gauge size :o dodgy lol

[aaronng]

Yeh thats another thing my mech didnt do, he worked on the tappets while the engine was warm, but he said that he compensated the heat by using a smaller gauge size :o dodgy lol

Agreed!

Oh yeah, MIRZ, if you want to do it yourself, make sure you get yourself some gasket sealant. Something like ultra blue.

[destrukshn]

it is still recommended that it has to be dead cold.

[EuroDude]

Well it depends on what temperature Honda specified the clearance to be.

Does anyone know exactly what temperature Honda specify?

[aaronng]

Well it depends on what temperature Honda specified the clearance to be.

Does anyone know exactly what temperature Honda specify?

I know.


Valve Clearance Adjustment
NOTE: Adjust the valves only when the cylinder head temperature is less than 38°C (100°F).

[EuroDude]

38c :eek: so that mech was right to warm the engine a bit.

[aaronng]

38c :eek: so that mech was right to warm the engine a bit.

It says LESS THAN 38ºC. 38ºC is not warm. It is cool. Warm is 50ºC. Your head should be hotter than the coolant, so it's over 100ºC when you turn your engine off after driving.

[EuroDude]

Alright so the ideal temp would be around normal weather temp ~25c.
Guess it wouldn't be a good idea to do it in Thredbo when its 2c lol