Anyone driven a 5th Gen, with ecu fuse pulled for a long period of time? - Honda Prelude Forum

J_Gray1 · 11-08-2001, 03:11 PM

I was cleaning the car today, and decided to pull the ecu fuse... not the radio fuse in the engine bay, but the 15 amp fuse by the driver's side kick panel. Of course, the engine light was on... but the vtec still kicked in and the response was quite nice, although I was afraid to leave the driveway. Any input would be great, I know the damn OBDII is always going to keep me down, but maybe I can just leave the fuse out every now and then.

Gray

cementups · 11-08-2001, 07:25 PM

I would ust un-hook the battery for a little while and that will reset the ECU as well.

Hawks10 · 11-08-2001, 08:43 PM

I heard some things about this too....does simply pulling the 15amp fuse under the hood reset the ecu, or do you have to have it out for a long period of time and drive like that?? I am wondering because I pulled the 15 amp fuse and put a new one in, did this reset the ecu?? If it did, I felt no difference, please tell me the easiest way to reset the ecu while still being able to use the radio, thanks

Prelude1897 · 11-08-2001, 10:28 PM

Either way you do it, the ECU will still reprogram itself. You should try leaving it out and see what happens. Maybe it'll be a good thing

Neulude · 11-09-2001, 01:19 AM

yeah, leave it out and see what happens when your lude blows up!

NAH...To reset the computer, I normally pull BOTH fuses. Leave them out for 20 min. reinstall, then reconnect battery. start and idle till normal engine temp is reached. GUARANTEE reset and you will feel the difference.
But you can try to drive without the fuse....when you smell smoke...then you can say

I shouldve drove with it in!
YOu're forgetting the fuse is there cause if there's an elec surge in your system, the fuse PROTECTS your ecu from anything more than 15 amps will FRY your ecu...then you can roll down the hill and think about doing that again...

11-09-2001, 02:21 AM

^ Dude that's very unnecessary...all you have to do is unhook the battery for like a minute or less..and you will feel a difference

marcucci · 11-09-2001, 06:16 AM

You guys should try searching... check out this link:

http://www.ntpog.org/mods/fifth-
afc/ecu.shtml

You'll need to paste the link together since the anti- h - a . n e t Nazis don't want you posting links to them.

I don't know what the 15A fuse does, but I would suspect it does something. Probably not very smart to leave it out, since that's not the one that handles the backup power that keeps the ECU from learning. You cannot disable OBD2 while the car is actually running.

Two-Five Boy · 11-09-2001, 07:56 AM

I can tell u what it does from first-hand exp.

I pulled the ECU (for reasons I don't want to talk about)and drove with it for a couple of days. Yes the engine light will come on, along w/the hand brake light for some reason. Anyways I drove like that and everything was fine, except ur speedo doesn't work unless u hit VTEC.

Then one day I was coming off the highway and stopped at a light, then.......................... silence!

The car STALLED!!!!

I tried to crank it but nothin, even when I replaced the ECU fuse. So what I wound up doing was re-setting the car by pulling out the clock/radio fuse as well, wait 15 mins, put both fuses back, then voila

the Lude came back!

So the moral of the story is don't mess w/electronics that the Honda goons spent months and yrs on developing, cuz they know what they're doing and we don't!!!

streetweapon · 11-10-2001, 12:47 PM

Whats all this waiting 15minutes about

There is a quick, an simple way to drain any left over power in your system....turn on your headlights untill then don't have enough power to run.

Flavour · 11-10-2001, 07:17 PM

guys, the memory in the ecu is very volitile, its not like there's giant capacitors in there...

here's my before and after dyno, all that was done was pulling the 7.5A fuse for 10 seconds...

http://members.home.net/flavour/1.jpg

i'd have to say based on this, the ntpog ecu switch is recommended. i did it

spite · 11-10-2001, 07:29 PM

Quote:

Originally posted by Flavour
guys, the memory in the ecu is very volitile, its not like there's giant capacitors in there...

here's my before and after dyno, all that was done was pulling the 7.5A fuse for 10 seconds...

http://members.home.net/flavour/1.jpg

i'd have to say based on this, the ntpog ecu switch is recommended. i did it

That could be margin of error, but it's nice to see a little boost. =]

Flavour · 11-10-2001, 09:08 PM

Quote:

Originally posted by spite

That could be margin of error, but it's nice to see a little boost. =]

maybe margin of error on a homemade dyno, but this is the most accurate car dyno in Toronto. there's another dyno in town that will probably give me my 200whp

plus all the runs were done in 4th gear, which is supposedly the most accurate. its cool listening to your car going 120mph inside a small room...

considering it was the 3rd run I would have figured if nothing happened the 1st run would be best because of any heat buildup. we didn't really wait between baseline runs.

i should add if you take off that spike on the first run the difference in peak hp is like 5whp, and the reset ecu dyno is always higher across the band. i mean these gains are similiar to what you'd see if you added a cai or exhaust. pretty good for $3 for a switch and some wire. i was skeptical at first myself. and you're right its not scientific proof or anything but i didn't plan on doing double blind experiments or anythng... take it for what its worth...

Kool-Lude · 11-11-2001, 12:12 AM

Where did all these crazy myths about how to reset the ecu come from? It seems like there is a post every month about this..and out of the wood-works comes these crazy ideas about the best way to do it. Doesn't anyone BUY and READ the manual?

Helm Service Manual (97-99), Section 11-37, ECM Reset Procedure: Turn the ingnition switch OFF. Remove the CLOCK RADIO(7.5A) fuse from the under-hood fuse/relay box for 10 seconds.

THATS IT...no disconnect the battery, no start the engine and run til warm, etc. Lets put this thing to bed once and for all. Sheeeez.

Flavour: for what its worth, my butt dyno(homemade too) can definitely feel a power increase when resetting my ecu (that is, if i wait long enough...i pull it every few days so it stays in happy mode). Need to do the ntpog switch one of these days.