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View Full Version : Rb25 Gurus, please help


singlecamslam
12-10-2013, 07:51 PM
This is kinda a long read, so bear with me. The motor at hand, 1997 rb25 s2

The problem is about the common stalling issue while blipping the throttle or coming to a stop, it would always stall. I have narrowed the problem to the IACV, and heres why i think this is so:

On dead cold starts, the car starts and idles at 2k like its supposed to, so i figure the air regulator is working properly. When the car hits 50+ degrees C, the idles drops and stumbles instantly like switch has been pressed. THis is when the car starts to stall when i blip the throttle, by the time it reaches 85+ deg. C, it stall much easier and constantly when i throw it into neutral.

I checked power going to the IACV plug, has power. I checked continuity between ECU pin 4 (as per FSM instructions) and plug, has continuity. But, when i apply a ground directly to the plug, the IACV works, i can hear air circulating and the car stops stalling. WTF? So for some reason i'm not getting a ground. And when i apply ground i cant change the idle no matter how much i adjust the screw, but it does idle, around 800-900, and most importantly doesnt stall, no matter how much i blip the throttle.

Can i just wire in a ground directly to get around this problem? Ideas? What could be going on here. Thanks for any help.

fliprayzin240sx
12-14-2013, 06:01 AM
Did you check everything else like your base timing and TPS sensor to make sure they're set correctly?

I can't remember now off the top of my head but the does the stock Throttlebody have water lines going into it like the SRs? SRs have a cold start pin that cracks the TB open when its cold to bump the idle up without the IACV.

Clean the IACV, then bump your operating temp idle to 900 rpm.

singlecamslam
12-15-2013, 07:38 PM
Update:
Car stalls even while AAC valve directly wired it for constant opperation. TPS adjusted: .5 closed, 4.29 fully open, cant get it any higher than that, Timing at 15 degrees, idles around 900 as it is, its not super steady, but not hunting either, slightly rough . AAC valve has been cleaned, tried a different MAF, still stalling.
The car does run rich, getting around 20MPG highway and if i hit the thhrottle forget about it. Checked for vacuum leaks 3 times now. I'm thinking about taking off the "HKS" BOV and plugging the whole to see if the BOV is causing it, bad 02 maybe? Hate having to hit the gas when throwing it into neutral.

fliprayzin240sx
12-16-2013, 02:05 AM
Did you pressurize your system to search for vacuum leaks? Base timing at 15*, 4th mark from the left? Plugs and gap? Checked your spark, make sure all cylinder are firing?

Also, know anybody with a spare ECU? I'd swap ECU just to see if that might be your issue.

Bracken
03-19-2014, 07:49 AM
sorry to bump up an old thread but i am having this same issue did you solve it?