I just finished swapping a JDM B16 into my GSR, cheap replacement for a blown B18c. Everything appears to be hooked up just fine. The car runs great, pulls very hard and I am not disappointed in any way... except the fact that I cannot figure out this idle problem. I didn't have the o2 sensor plugged in and got a CEL, so I figured that was the culprit. Not the case- CEL is gone, but still idles funny. I also tried bleeding the coolant, no dice. All of the vacuum lines appear to be nice and tight, so I'm lost. Upon cold startup, the idle shoots to 3k, and stays for a few moments before surging between 1500-2500rpms. Once the car starts to warm up, it will surge between 1000-2000 or so. I have a chipped P28 ECU , and this might be the problem?? When I still had the B18c installed, I ran the P28 for a half hour to drive the car home from where it was parked, and the idle was funny on that motor as well. I summed that up to the fact that I had bent valves, but I can't understand why the same thing is happening with the B16. It's in great running condition and I know for a fact there's nothing wrong with the internals, ie valves. Any ideas on what's causing this to continue? It's driving me nuts and the only thing from keeping this swap 100%. Thanks fellas.

 

Are you sure base idle is set correctly?

Also, is P28 ECU modified? ie. Hondata, or others...

Could be an issue if modified and IAC duty cycle not tuned right...

Let me know, it may just be something simple as well...

I'll be glad to help !

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hondatim &raquo;</TD></TR><TR><TD CLASS="quote">Are you sure base idle is set correctly?

Also, is P28 ECU modified? ie. Hondata, or others...

Could be an issue if modified and IAC duty cycle not tuned right...

Let me know, it may just be something simple as well...

I'll be glad to help !</TD></TR></TABLE>

Check your IAC is or FastIdleValve those more then likely are the culprit. This happens all the time. Since you have a spare b18c take the some of the sensors that you know are good and swap them.

 

Apparently this ECU is 'socketed' for Hondata, however, the tuner who I bought it from put just a baseline DOHC VTEC program to it when he rechipped it. I thought that 'socketed' just meant easy removal of the chip, ie the flip of this little toggle switch next to it. I haven't tried the fast idle valve yet. This could be the problem. I said that when I ran the p28 with my b18c, the idle was funny. Well, I switched my GSR T/B over to the b16 IM since the b16's tb didnt have a TPS or any of that **** on it. Maybe my fast idle valve is junk. I'll look into it and keep you guys posted. Thanks for the help.

 

I would also try checking the throttle position sensor, unerneath the throttle body.

 

TPS is on backside of throttle body. If it is any stock Honda throttle body, TPS is not adjustable anyway.

You said that it is a GSR T/B on a B16 I/M. I would definitely start with setting base idle first. This will most likely take care of the idle hunt issue. What happens is that the GSR throttle body idle set screw needs to be adjusted to correct idle to 700-750rpm with no accessories on.

Let me know if you need to know how to set it correctly...