I've got a 2000 Civic Si with a built b16a2 with just about 4,000 miles on it. The car itself, along with the starter and all sensors, has 44,000 miles on it. My car started and ran great with constant voltage or about 13.3 (via turbo timer) about a month ago. But eversince then my car would start progressively slower, ie crank slower, untill about 2 weeks ago where it just didn't have enough juice at all to start. So everytime i've been driving my car, about a 1/4th of the time I've had to jump it. My volts jump around from about 9-11 on my turbo timer now, when it used to be constant. I haven't changed anything on the car other than a new battery and brand new altenator which was just put in 2 days ago. And now the car seems worse, it won't even crank at all. I don't think it could be the starter, cause i can jump the car fine.

No clue whats next to check out and hopefully fix. Main relay? Any help is greatly appreciated.

 

tap the starter with a wooding handle of a hammer to see if the motor turn over. or take your starter to the autoparts store for a test. honda main relay are know to go bad. wouldn't hurt to take it out a resolder all the joints.

 

Could it be the starter? It starts fine when I use my battery booster pack. And I honestly have never even seen a honda main relay. I should check that out. Damn, i don't even know where its located

 

it's on the passenger side above the ecu.
here is the link show you how to fix it, if you need too.
http://www.integra.orcon.net.nz/relay

 

Alternator isn't making voltage (or it's not going where it's supposed to). It's simple enough. The question is why? The alternator is actually under the control of the ECU. The ECU can tell it to stop charging at various times.

The simplest thing is that this "New" alternator is bad. Beyond that you need to grab a meter and start testing. I consider 13.3 to be low. Normally I'd expect 14.5 volts.

Jump it, start it, then use a meter to measure the voltage coming out of the alternator. You may have a bad cable from the alternator, loose wire, the alt is bad or the ECU is inhibiting the alt. It's not that hard to figure out with a meter and wiring diagram.

 

definetely dont drive around like that,
you'll just drain your battery to death and ruin it.

Check all your grounds, thoroughly!
My battery wasnt getting charged and it turned out my transmission ground was on, but not tightened down all the way!

Also make sure the white wire, running from the fuse box to the terminal on the alternator is intact and both ends are secure. If there is some torn insulation or something it could hit on some metal and short out.
That wire carries the power current from the alternator to the battery.

good luck.
Also if you are not getting like over 13V at the battery, then you are not charging the battery.

 

Welp the altenator is an OEM Denso one, brand spankin new, not a refurbed one. The problem was happening before I even changed the altenator, i just tried a new one cause that was the next thing in line after a new battery. And it didn't fix anything.

Thanks for the link man, i'm gunna try that next after I check all the grounds. But i just don't get how my car could go from being perfect a month ago, then all of a sudden i have this problem. But hell, i guess **** happens. So I'm gunna check all the grounds and the white wire from the altenator, and hope its just something simple like that. The car's only got 44,000 miles on her, so thats why i'm kinda confused about why this would happen and what it could be. Thanks for all your help and i'm gunna check my grounds then I'll be back to say whats i find. Thanks again guys

 

Another really obvious thing is your battery could be bad. It's 4 years old which means it's getting pretty old. I expect 5 years out of a battery but, it all depends on how it's used. Sometimes it's longer, sometimes shorter.

 

Wish it was just the battery, but its only 2 weeks old

 

if its your main relay. i got one brand new sitting here. bought it from honda $75... 50 shipped and u can have it.

BTW check all your grounds. Especially the thermostat ground that one is a tricky bastard. it appears to be tight but it really isnt. or you could go to your local audio store and upgrade your grounds to 4 gauge on the tranny and Battery. and 8 gauge to the chassis from the head.

 

Welp, I checked the gounds and they are all tight, even that one on the thermostat - they're all good to go. I need to look at a ground diagram to be sure, but are there only two grounds that connect to the front of the car? Theres one from the valve cover, and one from the A/C area right? Just curious cause i found a loose bolt in the engine bay that looks just like one from the grounds that are in tact.
But if all my gounds are cool, the only thing left could be the relay i guess? I hear it clicking though when I try to start my car?

 

dont forget the power cable from the alt to the fusebox

 

is there something draining the battery when the car isnt running?

 

There shouldn't be anything draining it. I've got a turbo timer and alarm, but i doublt they're messing something up. I'm gunna check the main relay and then the alt. fuse and hope something is wrong with them. I'll keep ya posted. Thanks guys!

 

check yo grounds sonnns! bah i dont know

 

how do you check alternator for the voltage? Btw how can you tell if the main relay is bad?