I have a 99 civic lx with a 96 jdm gsr motor. After the swap my headlights and interior lights dim depending on rpm and if I push down on the throttle. Above 4k the lights go to normal brightness. Below 4k it only dims if I'm on the throttle or at idle. I changed the alternator and it still does it. The old alternator was good too. I've checked all my grounds and the wiring and now I'm stumped. I read about the service bulliten. Also i don't have an o2 sensor after the cat would that be a problem... cause there isnt a check engine light. thanks.

EDIT:::: i read about cutting the altc wire would fix that.... is this true, any negitive effect to this?


Modified by 994door at 9:36 PM 6/21/2007

 

bump because i have the same problem.

 

same problem...and i also am open cat rite now too

 

I have the EXACT same problem also. I just swapped in a GSR motor into my 98 civic. I didn't have this problem with my b16a... I cleaned all the grounds, and tried a different alternator. Some one has to know????

Well, i found this thread ^ on a HT search and read alot more with people having the SAME problem. Everyone just says "check your ground" " sounds like a ground problem". Well like i said I cleaned them all and even add a ground to the alternator. I found a post where someone disconnected the ALT signal wire from the ecu harness and the porblem went away. Has anyone else done this???

I did the alternator test thats in the haynes manual and it says at idle I should have around 13.5v. Well I have 12.6v. It says with a load at 1500rpm I should have around 13.5 to 14.1 v. I have 12.6 - 12.7v. So something is not right.


Modified by hondadriver at 3:59 PM 9/1/2007


Modified by hondadriver at 4:01 PM 9/1/2007

 

bump. because a couple buddies i have ran into the same problem. haha both have gsr swaps.

 

Alright, I remember reading some where that someone put a bigger pulley on their alternator and some one said that the alternator would turn spin alot less due to the bigger pulley. So with that said, when i pulled my b16a out and intalled the B18c GSR engine, when I went to install my belts (a/c, power steering, alt) the a/c and power steering wouldn't fit, and the ALT was bolted down alittle closer to the block due to the short belt. So I thought is the CRANK PULLEY bigger in diameter?? I didn't measure it but it DEFINITELY looked bigger. It was noticebly bigger. So today I looked up OBD1 and OBD2 b18 and b16 crank pulley part numbers:

95 GSR: 13810-p72-013
97 GSR: 13810-p72-013

94 Del Sol Vtec: 13810-p30-003
99 civic si: 13810-p2t-003

even thought the center P30 and P2T are different I'm pretty sure the b16 pullies are the same. So the B16 and B18 pullies have different part numbers. Which looks like they're different pullies. When I had my b16a I never had this problem. It looks like alot of people have had this problem with their GSR's, is it possible that the GSR crank pulley has a bigger diameter causing our alternators t work half the speed and not charging correctly?????? I don't know anything about pulley size and the speed of something turning when the pulley are changed, so i may be way off or completely wrong so HT let me know if this is possible.

last night I cut the ALTC wire and the dimming problem went away. Everything works fine, but I don't like cutting wires are doing any kind of hack work, i rather try and figure this out so everything works the right way...

EDIT: I just did a search on here and I found 2 threads where some says that the b16 crank pulley is smaller then the GSR. So if I pick up a b16 crank pulley, you guys think that'll solve my problem???????

https://honda-tech.com/zerothread?id=1931936

https://honda-tech.com/zerothread?id=1830782

 

Cant you just run the GSR alternator? Or am i missing something here... i mean, unless you relocated the alternator, the crank should be spinning its stock alternator at the right speed.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by bobjohnson &raquo;</TD></TR><TR><TD CLASS="quote">Cant you just run the GSR alternator? Or am i missing something here... i mean, unless you relocated the alternator, the crank should be spinning its stock alternator at the right speed.</TD></TR></TABLE>

Well I new a different alternator won't make a difference as far as a b16a and b18c, because their both the same, and the second alternator I used was off a 95 GSR. LOL, this is so ****** gay, all i did was replace the engine from a b16 to a b18, the alternators mount in the same place, they both use the same alternator. I haven't changed any grounds or anything with this swap the only really difference between the motors is the crank pulley. Maybe the JDM ecu's read a lower voltage or something?? I did a google search and found out the JDM ecus don't even have the ALT C (control) circuit in their ecu's. I installed a Blox IM on the motor and I'm running the engine off my civic si P2T ecu until I get my p28 ecu chipped and tuned. And its running great with the ecu, its basically the same setup as a b16 except for more displacment.