OBDII ECU

Post by **sproggy29** » Wed Jul 23, 2014 12:57 pm

Merlin wrote:It is always best to reset the ECU once you have installed a mod, be it OBDI or OBDII. For a 5th gen disconnect the battery for 30 seconds.

Manual or auto box? Did this juddering happen as soon as the new exhaust was fitted? If fuel consumption is way up and the only thing you have touched is the exhaust I would point the finder at the O2 sensor.

auto but in semi all the time, apart from when it decides to be an automatic when changing down on its own.

Post by **Merlin** » Wed Jul 23, 2014 1:09 pm

I would say that the the two things are unrelated. Auto boxes can play up especially if they are not serviced regularly. Have a read of the blurb below written by a member with experience of the 5th gen auto box. If the gearbox fluid hasn't been changed I would get that done as soon as possible.

ubersonic wrote:Ive been compiling this list in work to pass the dead time (I cant fix what aint breaking down ) hope its helpful to somebody, its by no means complete but I thought I had enuff for a 1st post:

Whats the difference between Tiptronic and sportshift?
Short answer: Sportshift is correct, Tiptronic is wrong
Full answer: Not everything that does the same thing does it the same way, to the driver a GM automatic transmission and a Hondamatic transmission both appear to function the same although the design is very different, the same is true of the Honda Sportshift transmission and the Porsche Tiptronic transmission, they offer the same semi-automatic features but via different design NB: you do get Tiptronic Mitsubishis and others as they lisenced the technology from Porsche.

I looked on Castrols website and it said my 5th gen SS only needs Dextron 2 or higher and they reccommend their Dextron 3 ATF is it ok to use this or halfords stuff?
HELL NO!!! that may seem dramatic but believe me it isnt, ill be clearer: Using anything lower grade than Honda Z-1 ATF will cause long term damage to your gearbox! see below for the explanation of this.

So what the hell is the problem with these gearboxes? they have a rep on the internet as being lemons.
Well the is various information on US forums that the USDM gearboxs suffered from manufacturing problems (i.e http://hondaprelude.to/forums/showthrea ... sportshift) but the main culprit was the prelude itself. Regardless of which generation you look at the car was always designed to be cutting edge technology wise and it was only the second ever roadcar to feature a "manumatic" style gearbox following hot on the heels of a Porsche earlier that year.

This presented a problem as the prelude was esentially running a prototype transmission and Honda basically gambled that they had got everything right, they reckoned that a 60,000 miles service interval on the box would be regular enough and they gambled that their new Z-1 ATF would be more than good enough to keep things running fine, they lost both bets.

A lot of people reading this will now be confused as im effectivly knocking the Z-1 ATF and whenever somebody asks on the internet what ATF to use in 99% of the cases people tell them "Honda Z-1, nothings better", the reason they say this is because thats what they were told when they asked, and so on, and so on, right back to 1997 when Z-1 was the only thing you could put in a Prelude. The thing is 90% of all automatic transmission failures are due to heat, the hotter things get the worse job the ATF does and the more succepable to wear and damage the mechanicals are.

By the time the Prelude was discontinued Honda had lowered the ATF service interval to 30,000 miles but this is usually considered to still be too high as Z-1 will be past its best many miles before then.

Why didnt Honda fix it?
Well to be blunt: money, it would have required modification to the ATF cooling system or development of a new ATF that was superiour to Z-1 (or preferably both) and this would have cost them more than it would to replace any transmissions that failed within warranty so I guess they chose the cheaper option of not bothering, either that or they didnt understand the scale of the porblem. They did however slightly modify the transmission itself in 1999 to try and make it less susceptible to heat but this was only a minor improvement. However they then made the mistake of using the gearbox in the Accord which was alot more popular than the Prelude and so facing consumer wrath they were forced to increase the warranty for it and the then discontinued 99-01 Preludes to 100,000 miles.

Can anything be done about it? I don't want my car to die
Two things, firstly full replacement of whatever ATF is in the car with a decent synthetic ATF, this isnt 1997 and ATF's that surpass Z-1 have been around for some time. Amsoil synthetic ATF is highly reccomended around teh interwebs, I personally use Fuchs 4400 synthetic ATF but im wierd a guide to replacing all the fluid (not just whats in the reservoir) can be found here: http://www.preludeonline.com/f60/finall ... ude-69996/ a better ATF makes a big difference as it does its job better but also runs cooler which is kinder on the gearbox and also reduces engine temps as the temp of the engine coolent is reduced (ATF pipe runs through the radiator for cooling) by all accounts up to around 20 degrees Fahrenheit.

Secondly, install an ATF cooler, a guide to this can be found here: http://preludepower.com/forums/showthread.php?t=289238 this is the same one I use and I can confirm it makes a big differnce helping cool the ATF further for more benefit to the gearbox and engine.

If you perform both of the above upgrades on a fully working M6HA and change the ATF (just what's in the reservoir not the whole thing this time) every year or 15,000 miles (whichever comes first) then barring any manufacturing defects with your gearbox it should be no more prone to failure than any other Honda gearbox. But even if you perform them on one exhibiting signs of damage (like mine was) its still worth it as its not that expensive and will smooth out hard shifts, make the ride better and should prolong the time to any gearbox failure.

Why is the 0-60 time so much slower than the manual?
Because the Geforce GTX260 is faster than the Radeon 5830 which is faster than the Geforce GTX260, that is actually true depending on the game you benchmark as things like PhysiX, OpenGL and Direct3D all favour different cards. My point is that test results depend greatly on the test method and automatics were always tested for 0-60 by the manufacturers in drive, when Porsche released the tiptronic 968 they folowed the status quo and obtained their results in drive, as did Honda when they released the SportShift Prelude.

Today manufacturers of semi-automatic cars test them in "manual" mode which is why Porsche claim their Tiptronic Boxster (may be a Carrera, not sure off hand) is faster than their manual. Of course it all depends on the driver but assuming the cars are identical bar gearbox and the drivers are of equal skill then its a general consensus that the SS Prelude is between 0.5-1.0 seconds slower to 60 than the manual.

Thats all I could think of for now, hope any of the info helps

89 UKDM BA4 4WS (resto job!) · Post by **wurlycorner** » Wed Jul 23, 2014 1:19 pm

Awesome

almost enough to make me banish all my worries and buy a tiptronic lude now!*

*to stick the 5th gen gearbox in the 3rd gen

Post by **sproggy29** » Wed Jul 23, 2014 7:00 pm

wow! That's some work there, thanks Merlin. I have just finished work so will read it properly when i get in.
thanks again

Post by **sproggy29** » Thu Jul 24, 2014 6:10 am

I think then I need t change my GB oil, and if I am reading it right that's every 15k? that okay though that's like once a year but for a positive influence twice a year? and then the best oil to get? its not cheap stuff is it! cheaper than a new gearbox or leaving bits of it strewn across the a41 though....

To work I go but Halfords is just around the corner from my work, do they sell a decent one in there or should I go to my local Honda dealer and get it there?

Post by **sproggy29** » Thu Jul 24, 2014 6:21 am

Is Castrol ATF DEX II Multi vehicle any good?

then I found this:
The ATF-DW1:
Maintains optimum shift quality over a long period of use.
Ensures stable consistent operation over a wide temperature range.
Has a lower viscosity for improved fuel ecomomy.
Has a low oxidation rate for longer improved long-term stability.
Protects transmission seals and components from corrosion and excessive wear.
Is formulated specifically for newer Honda vehicles.

ATF-DW1 has replaced ATF-Z1. This bit

Part Number-08268-999-01HE

Post by **sproggy29** » Thu Jul 24, 2014 6:36 am

Just read the link to changing the GB oil, no pictures

Want to get this done tomorrow, anyone got any pics of the resi and underside plug?

89 UKDM BA4 4WS (resto job!) · Post by **wurlycorner** » Thu Jul 24, 2014 9:02 am

As it says in the gumpf above, Amsoil ATF is highly recommended...

You can get that from Opie oils.

Andrei2j · Post by **Andrei2j** » Tue Sep 09, 2014 12:36 pm

Reading this now after my gearbox is about to die . And after I already bought of EBay 2lt of Honda ATF ...

Question :

Is the gearbox in anyway related with the fusebox inside car ?
After I was trying to find light fuse , i replaced some of them as they had different voltages . After that everything went looney with my gearbox ...

89 UKDM BA4 4WS (resto job!) · Post by **wurlycorner** » Tue Sep 09, 2014 4:08 pm

Andrei2j wrote: After I was trying to find light fuse , i replaced some of them as they had different voltages .

I guess you mean different current ratings (10Amp, 15 Amp, 20 Amp etc.)
There are supposed to be different ratings in different circuits. The correct rating is shown on the fuse box lid sticker.
Do you mean the ones that were fitted had different values to the ones shown on the sticker and you've put the correct sized ones in now?
Putting the fuses back to the correct rating wouldn't directly have caused any problem with the gearbox, no.

I'm not a 5th gen auto expert, so just thinking outside the box...
Did you change the fuses with the engine running?
Is there some kind of reset procedure you should go through with the auto box though, if you've disconnected the battery?