Tonight I am going to experiment building a fastidle valve using a $15 canister purge solenoid from any older or newer GM vehicles. The part and the pig tail could easily be found at the junk yard on any GM vehicle. Originally I wanted to use GSXR Secondary AIR valve ($7 shipped), but I feared I was not going to be able to find the connector.
The goal of this project is to raise my idle by at least 200-300RPM. I'm shooting for 900RPM hot, and 1200RPM cold (< 100F). My warm-up enrichment ends at 90F.
Oreilly part #: CP561
It also uses the standard GM two-prong connector. More updates tonight with pictures, and hopefully video of solenoid in action.
I spent 30 minutes pondering how to mount this. At the end of the day, the best place to mount it was right on the metal fuel line. It works great. Stand by for video.
Please excuse shaky and slightly out of focus cell phone camera. Here is a video showing Fast-Idle feature in action.
I am toggling between the Fast-Idle temperature to demonstrate the workings of the solenoid.
This one was perfect --- it was easily available form local parts store, and the connector is the standard GM two-prong plug. The price makes it easy on the wallet too..
Stock type4 idle RPM spec is 975--- keeps the hot oil pressure gremlin away.
My warm up enrichment ends at 370F CLT. (~450F CHT)
(I turn the indicator off, as it is always active)
It does go to zero in the middle, but it fattens up a LOT >285 (effective ~375F CHT)
I also tweak the timing continuously over the same range using the cold idle feature, and kick the CLidle target up when hot, as the fan keeps things cooler at ~1200 RPM vs. 975. Idle timing goes up as well, reduces CHT, and keeps the oil pressure up.
Don't limit your settings with a watercooled mindset, an aircooled engine operates over a much wider temperature range...
A given "perfect" tune is only "perfect" at one temperature etc.
MS provides the tools to make it right over the whole range and also allows you to compensate for some of the aircooled engines peculiar requirements.
You can probably PWM that valve if the driver is up to it.
(frequency needs to be found by experiment:
The right one does not annoy you or melt the valve or driver)
Good find!
Addendum to Newtons first law:
zero vehicles on jackstands, square gets a fresh 090 and 1911, cabby gets a blower.
EZ3.6 Vanagon after that.(mounted, needs everything finished) then Creamsicle.
I am using GM 1bar MAP sensor.. Another $15 part. I have a thread on advrider, and on itinerant air-cooled site. I will be writing a quick conversion guide on IAC site, and maybe X-post on shoptalkforums once I sort all my bugs out.
