hello everyone,
i bought a 98 honda civic ex about 1 year ago and basically ran into a hack job and had to find out the hard way about the problems with the car. well i guess the car was an auto to begin its life when i bought it it was a manual and the previous owner took the check engine light out(never told me anything). anyways to make a story shorter i had to get a manual ecu, manual thottle body, intake manifold and other parts to make the check engine lights and codes go away, so finally got it all straight and then took it in for inspection and got evap cat and o2's not ready, they told me to drive it for a week and bring it back and to go over 55 mphs in my travels, brought it back and still not ready with over 200 miles of driving, seached this forum and found that he didn't even have the 7.5 back up fuse in, so i put it in and have driven it about 138 miles and still not ready, and not the heater fan stays on with that fuse it when the car is off so i trickle charge it every nite so that the memory says in the ecu. it says the h02s are ready but not 02s, in new york state i need one of these monitors to be ready. the check engine light isn't on, i've been trying to do suggested "drive cycles" but cannot find the acually honda civic drive cycle. the car is just getting to me cause i cannot get it inspected, just wondering if anyone has any suggestions. thanks for any help

 

I think this text contains the key information but I can't understand exactly what you are saying. Please clarify. Nonetheless, it appears that you may have a problem with the under-hood fuse/relay box or its wiring.

 

Check that back-up power is actually reaching the ECU by measuring the voltage on that pin. The back-up fuse also feeds the radio, and if someone has hacked the radio wiring it could have a short there.

Also if the ECU doesn't power down (to just back-up power) with the key off, that might confuse it too.

Finally the '98 is known for the problem of frayed wires behind the engine, which will blow fuse #15 under the dash and cut power to several sensors. This will cause the CEL to stay on all the time though.

 

Ronj: sorry for the miss confusion, what i'm trying to say is that with that when i put in the back up fuse my battery would go dead if i let the car sit, cause the a/c climate control gets constant power with that fuse in and the key out, like if i have the fan set on 1,2,3,or 4 the fan with work with the key out also the lights for like desfoster settings. so this is why i keep the battery on a trickle charge. also there is an aftermarket stereo in there that keeps memory and shuts off with the key. also the car has headers and a catback exhaust could this also be why they won't set?

i belive the power is actually reaching the ecu cause when thef fuse was out the everytime i turned the key off and then back on the ho2s would say not ready, with the fuse in and after i take it for a drive and then turn off the key and back on they are ready, but i could be wrong. And the cell isn't on. I checked number 15 fuse and there is a 10 amp fuse in there that isn't blown, also while i was checking that there is no fuse in number 28 witch is 28 RADIO CLOCK 10 (*15) 10-7 Stereo radio tuner (’96-’98 models), could this be my problem?


well anyways thanks for all your guys input i feel as i'm getting closer to the problem and might be able to enjoy my civic legally and doesn't just sit.

 

You should check the wires behind the radio, that's the only other place the BACK UP circuit goes I think except maybe to a factory alarm.

If you're saying putting the fuse in made it quit throwing the "not ready" code, and the CEL is out with no other codes, it should be able to pass a smog check (at least on those counts), right?

 

This information suggests to me that your under-hood fuse/relay box (see diagrams below) is a likely source of your ECU problem and may need to be replaced.

Specifically, fuse 47 under the hood protects the circuit for storing memory of radio stations, clock time, and ECU information such as CEL codes that are thrown. By contrast, fuse 55 under the hood protects the circuit for the blower motor fan. Therefore, insertion of a new fuse 47 should not affect whether the blower motor runs or not. These observations suggest to me that the fuse 47 and fuse 55 circuits are inappropriately connected, possibly through a short circuit in either the under-hood fuse/relay box itself or in downstream wires for these two circuits. Locating this short circuit (or improper wiring) will likely solve your current ECU problems.

 

I think you are right, looked under the dash and wow what a mess, i mean wow, there is viper alarm system in that also functions the switch for the shaved door handles and just looks like a total hack job, just trying to trace the wires from the underhood fuse box to the climate control to see if there is any slicing there, looks to me that i might need a new wire harness under the dash and start from square one, i just don't get that the h02s are ready and other things are ready just won't run the tests for the cat and o2s and evap i guess. but thank you guys for the help and narrowing down everything for me

 

I think the additional electrical load of the blower on the ECU memory circuit is causing inexplicable ECU malfunctions. Maybe disconnecting the blower motor connector will restore ECU memory function and allow you to pass inspection. A worst case scenario is, however, that the short circuit/rewiring has permanently damaged the ECU.

 

okay i found a white wire with a blue stripe on it that is in a big spool of wires above where the blower goes, the wire looks like it was melted a little bit and is bare for about 3 inches the previous owner had some electrical tape over it, from what i see from your diagram the 47 fuse says its a white/blu wire. it doesn't look like its touching any wires, but maybe it is shorted. should i just try to replace the whole wire? what would u suggest, i will get a picture of what i'm talking about. i will try to disconnect the blower motor and drive it tonight and see if that will make it so i pass inspection. i was also thinking about if i could some how wire directly from the ecu to the battery with a fuse for the memory? not quite sure if that would work though. thanks again for your help

 

ya that white wire is melted all the way down to one of the radio connectors or security connector so i'm sure its melted and touching another wire that powers the climate control must be it. so i think need to find a wireing diagram and find out were that wire goes to and hopefully replace it from the fuse box or is it just not that simple?