John, The connection to my AC Compressor is a White wire with a Green stripe, and that color wire is not on your list. Have I got the wrong wire? If not, where does this White/Green lead to if not the Idle Controller. Another question I have is WHY ME?! Noooo, the question: This White/Green wire has a connector on it, but the SD508 has no place to connect it, so I have spliced into the AC Clutch on wire. Did any of the compressors come with a cicuit built in with a diode or something, that I might be missing? Kim
----- Original Message ----- From: "John Bange" <jbange@GMAIL.COM> To: <vanagon@GERRY.VANAGON.COM> Sent: Sunday, August 17, 2008 11:06 PM Subject: Re: Idle Relay - Idle Valve match?
> > I did swap out the idle relay (controller) and it acted exactly the same > > way. > > Heh. Well, then I betcha' THAT'S not it! Back to the drawing board... > > > Anyone (who knows these relays) think it might be a bad connection, wiring > > or a ground? I cleaned things up pretty well, but it's always possible to do > > more. > > I'd say that grounds are ALWAYS a suspect when you have weird > electrical "Heisenbugs". That was one of the alternate theories that > occurred to me today. > > > Why would it act up when it gets warmed up, but be OK when cold? It gets the > > signal from the temp sensor obviously. > > Indeed it does. The idle controller has the following connections: > RED/BLK - power from ignition switch > RED/WHT - power from fuel pump relay > WHT/YEL - power steering high pressure switch > BRN - ground > GRY - coolant temp sensor > RED/BLU - throttle valve switch > WHT - output to idle valve > YEL - output to idle valve > GRN - hall generator (RPM signal) > > The unit does indeed watch the coolant temp sensor, so that's always a > possible source of trouble. A marginal connection could cause the > trouble you describe. Excess resistance on the wire wouldn't affect > the behavior of the idle controller when cold, as the temp reading > starts off below whatever minimum "cold start idle adjustment" > threshold there is; but as it warmed, the idle controller would > perceive it as still being cold, perhaps even intermittently, causing > excessive idle air bypass. A quick check of the gray wire should tell > you if you have a resistance problem. > > Another possibility is a gummy idle valve not responding fast enough > at certain ranges of opening, but that one seems unlikely. > > Probably not what you have going on, but worth mentioning: I once had > a weird idle surge issue that turned out to be a loose distributor > collar bolt, which I'd forgotten to tighten after adjusting the timing > last. As I recall the distributor had "migrated" almost 10 degrees > off... > > > Does anyone have a diagram of what's going on inside this relay? > > Well... I kinda have one, but it's not complete and what I do have > ain't pretty! "Relay" is really the wrong word for it. It's actually a > hand-tuned analog computer. It's the sort of device electrical > engineers used to stay awake at night thinking about, before the > advent of digital microcontrollers made solving such problems trivial. > Imagine, if you will, designing a machine to keep an engine running at > one of three or four predetermined numbers of revolutions per minute, > with neither the ability to explicitly count revolutions, nor mark the > passage of time. It's beyond me, it is. > > > -- > John Bange > '90 Vanagon - "Lastwagen" > '90 Vanagon GL - "Wiesel" > |
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