The Yamaha Road Star Warrior Forum

I am looking for some advice with a customers bike I am working on.  It's an '06 RSW That has been to two Yamaha dealers and is still not operating correctly.  The bike does not go into its warm up idle.  When starting cold it does not want to run, stay running until warmed up.  The bike has a Barons big air kit, PCIII usb, and V&H Pro pipe.  I have adjusted the TPS on the bike along with on the PCIII, sync the throttle bodies, hooked the PCIII up to digital ground, installed a custom Map, adjusted the map at idle... none of this has helped.   The bike runs  great down the road, just does not like to idle when cold.  It also has the Barons relocation plate for the coils and IAC motor and sensors.  Anyone seen this before??  The IAC seems to be working , well I can hear it working.  All the hoses are going to it as well.  Anyone have any ideas on this?  Thank you.

I hate to ask, but have you turned the gold knob under the seat to raise the idle to about 950-1000 rpms?  I don't have a PCIII, but have had issues in the past when the idle was too low and the bike would stall out when I pulled in the clutch while cold.  Also, could the clutch be out of adjustment far enough to be slightly dragging and killing the motor.  I'm sure one of the site masters will chime in shortly with all sorts of electrical things to try out. 

 It's the engine tempreture sensor, I had to replace mine for the same reason, curedit right away

if you look for it on the parts fiche, it's called a thermo unit SKU: 5PX-83591-00-00

When you set up the PC3USB after digital ground (perfect install) did you set throttle position to zero before setting the idle rpm (see http://rswarrior.com/forums/p/18636/303297.aspx#303297 ).  If you did this step, then I agree next thing to check is temp sensor:

Washingtonwarrior:

 It's the engine tempreture sensor, I had to replace mine for the same reason, cured it right away

if you look for it on the parts fiche, it's called a thermo unit SKU: 5PX-83591-00-00

Check engine light on? Any  problem codes displayed in the clock window?  

Cold bike, before starting: Check that the two small hoses on the LCV are connected to the throttle bodies. Take the small filter off the LCV hose. I think your calling it the IAC, idle air control. Start the bike & check with your finger for vacuum. IF you have vacuum the LCV is operational. Reinstall the filter. If no vacuum the LCV is defective or the large inlet hose or port is plugged or the hoses from the throttle bodies are kinked/plugged. Repair as necessary. Be sure no one has tied the two throttle bodies together with a jumper hose across the LCV vacuum ports.

If you have vacuum on the large hose for the LCV & the two small hoses from the LCV are connected to the throttle bodies II suspect the oil temperature sender, ambient air temp sender or the cylinder temp sender is/are not functioning properly & is/are not letting the ECU know the bike motor is cold so it can go into the enriching mode for cold start. Check the connections first. You will need the shop manual to test the senders. I do not have access to mine at this computer. Perhaps one of our astute members can chime in with the test procedure & ohm readings. If the senders check out ok I would open the wire loom & look for hacked wires due to a careless coil & sensor relocation job.

.Also: Check the throttle body for the rear cylinder for a vacuum cap on the port that the AIS was connected to. This is the metal pipe that points to the left side of the bike.

Check the intake manifold bolts to insure they are tight. You can use WD40 to spray around the intake to check for vacuum leaks with the engine at idle. If the rpm's increase when you spray its sucking in the WD & you have a gasket leak.

As mentioned the hot idle speed should be 950.

Thats all I have for you after a 19 hour day. If I come up with anything else after morning coffee I'll post it.

 betcha when it's all said and done, it ends up being the thermo unit. Only reason I say this is I spent enormous amounts of time checking everything else and even tested the tollerences of the thermo unit (which showed ok during testing, found out later, it didn't consistantly test OK) This stupid thing is very fragile and it's only job is to tell the ecu if the engine is hot or cold. If you have access to another warrior or the sensor, swap them and see if it works, it'll take ten minutes on a bad day. Just be careful not to "toss" either of them on the bench while testing, that's about enough shock to make the stupid thing stop working.

You probably have a service manual since you are working on a customer's bike.  The sensor test data is on pages 2-17 to 2-19 (and as referenced).

Service Manual: http://www.paulmilner.com/yamaha/handbuch/warrior_service.pdf

Other Helpful: http://rswarrior.com/forums/p/54664/726842.aspx

Again, if you set throttle% to zero before setting rpm as above then I'd replace the thermo unit or at least test it a few times, its the logical problem based on your initial post.  Its also one of Woody's possible conclusions (Churchkey) so its a good step to take.

I wonder if we'll ever find out how it turned out