2006 DF50 idles at 2800 rpm

[Trebleplink]

Hi folks - I left my 2006 DF50 in the barn for 4 years and couldn't start it after hitting the usual suspects. It's been a great engine - now with 450 hours on it. (I would much rather hire a Suzuki mechanic, but after calling all the shops nearby and Nashville, nobody works on Suzuki, excepting 1 who is 6 weeks behind.)

I was able to troubleshoot it to a failed high pressure fuel pump. I replaced the whole VST with new yesterday. Now, it's a bit hard to start, and it won't idle - it runs about 2800 rpm no matter what I do. Per the shop manual, I pinched off the idle air valve hose and tried to adjust the idle screw - it did bring the RPMs down a bit but still way too high. In the past when adjusting the idle air screw, I could easily set it at about 800 rpm.

I can't figure out where it's getting air from - the throttle body butterfly is closed, and the idle switch on the throttle linkage tests good and is getting pressed in. The intake manifold gasket was in new condition, and on inspection, it looks mated fine. The engine is not offering up any trouble codes. All suggestions are welcome, including a Suzuki mechanic within driving distance who's willing to work on it...

Chris in Bowling Green, KY

[Triton2300]

No expert but I have read the IAC valve controls idle speed.

[ECU1984]

you may a faulty sensor somewhere, I believe some sensors when faulty tell the ecu to advance the timing (idle high).
Are the thermostats opening?

[Trebleplink]

Yes the IAC is controlled by the ecm to augment the idle screw setting. The symptoms scream vacuum leak, but the intake maniflold looks well sealed and I don't see any thing wrong.

SO, I located a Suzuki dealer in Eddyville Ky who wasn't 3 months behind. He attached a computer to the engine and the diagnosis was VACUUM LEAK. There exists a hose fitting under the intake baffle in the front of the engine that is very hard to see without removing the baffle (again) and I was so focused on the cylinder side of the intake manifold that I missed putting that hose back on.

Had the C-Dory out yesterday and today - Zuki ran great.

I bought the adapter plug and the Suzuki software, but that was some years ago and I can't find the disk ...