Thread: Low Stumbling/hunting idle thread (Auxilary Bypass Valve). Was Coolant Temp thread.

Haha I guess I am lucky then, my B13 has no PS, no AC, and the relocator kit! That's one of the easiest places for me to reach!

Sup, Reesy-Peesy!

I have one installed.. IMHO, I think that the 300ZX fuel filter last longer & dont blockup as bad...

my problem is backwards... the CTS (like the caddy)... just to be shure and we don't get lost in translation here... is the red cube thingy on the intake close to the wiper motor right?.... cooos my fans wont go on unless i un plug that or turn on the ac.... if you got it in autozone, could you tell me the part number or any other reference as to make my life a little bit easier and go buy one so my car won't heat? thanx! and great to hear you fixed your problem .... heating problems suck!

ok.. did a little search... is this the one you used?

http://www.autozone.com/addVehicleId,1965202/initialAction,partTypeResultSet/initialN,15900113/shopping/vehicleSelected.htm

Duralast / Coolant Temperature Sensor SU4115

Pretty White,

I had similar symptoms, hard cold start, dive bombing idle unless the accelerator was depressed, lasted for about the first minute to ninety seconds after startup. What fixed it was replacing the Air Regulator with a known good unit. The assembly works like this: There is a bi-metalic strip in there, which has a tab on the end which actuates a rotating shutter assembly. When it is cold, the shutter is opened about 1/8" or so, allowing bypass air to enter the intake, and thus accounting for the combination of cold engine/closed TB. As the engine runs during warmup, battery voltage is applied to the bi-metalic strip, heating it up and bending it and thus moving the aforementioned actuating tab that then closes the shutter gradually over the course of 60-90 seconds. After verifying the non-operation condition is not a simple electrical disconnection, operation of this assembly can be checked by removing it from the underside of the intake plenum, and looking through the air passages; you should see at least 1/8" of daylight through it when cold. If it is warm out (and as a double check), chuck it into the freezer for a bit to chill it out, and recheck; no daylight, no worky. It may need cleaning/adjustment. The other part of the diagnostic is after establishing that it is open, apply 12V to the leads to see if you can get it to close (again, takes about 60-90 seconds). If it closes off, you are in business.

It is a bear to get to (on the high port, anyway). Crappy job, but I believe this will resolve your issue.

Let us know how you fare with it!

Darrin

Yes, it was the SU4115. WOrks like a charm. Duralast stuff works pretty good. As a matter of fact, one day I had to get a spark plug coil for my 97 Maxima (the ones on top of the plugs) and inside was an authentic OEM Nissan coil. Duralast batteries are damn good too. Turst the part. Mucho cheaper.

Checked the price here in the mexican autozone... its almost $35 dollars at current exchange rate! and it takes 10 days for it to arrive... but i can get the original in less time (1 week) for $70 dlls... soo i'll stick to OEM...

Wow. I think mine was $12 at advance auto haha

http://www.autozone.com/shopping/repairGuide.htm?pageId=0900c15280069f69
Autozone, WOW!
So which one is it that I am changing?
http://www.autozone.com/shopping/repairGuide.htm?method=relatedParts&partTypeCode=207

Also for those who do not know what we are talking about this is what happens:

So why does the extra air going into the intake causing the engine to stumble? Is the valve being stuck open or is it closed causing the stumbling?

Found a simple explination: