Has anyone ever had an idle issue that was fixed simply by cleaning the throttle body?
I was talking to a tuner and he told me that a dirty throttle body can cause an engine to stall once it’s warm. I guess I see the theory behind it, restricting the airflow when closed. But goodness, how dirty are we talkin’? I dunno seems like it’d have to look like a used charcoal grill before it would choke the motor down.
Google says it’s plausible. Google also says not to clean them for risk of damaging the non-stick surface. If the non-stick was working it seems like you wouldn’t be cleaning it anyway.. Google also says something like, “a greasy film can cause turbulence and yada yada.” Dirty TB’s every give y’all the fits?
I found this nifty little device but I can’t find a vendor. I think it’s wholesale only. https://m.youtube.com/watch?v=x8C_qtxdnOc
Three things come to mind here: two involve the type of TB, the third a factory-applied coating Ford recommends NOT be cleaned; that I cannot attribute to which kind of TB it applies to.
Cable-operated TB always closes down to a fixed stop, never tightly shut, though, to prevent jamming shut. Buildup of carbon there affects air flow which normally passes through the clearance, regardless of PCM positioning of the IAC (or ISC). So, yeah, I've cleaned them, seen improvement.
Drive by Wire imposes some other considerations. With DBW, the plate is always held open a few degrees while at rest, with KEY OFF, held in position by a counter-spring opposing the main closing spring, against a physical stop. KEY ON immediately CLOSES the plate tight shut, the TPS output is compared to the number expected, if passes, plate immediately returns back open against that stop. This always-performed test upon turning KEY ON is to prevent unexpected TPS failure from causing a runaway, as some imports did in early 2000s. The test is fast, done before the key hits START. If the test FAILS, brother, ya got trouble; initially, usually, a "Forced Engine Idle" code, or worse.
So, with DBW, carbon buildup may prevent expected movement of the TP to some extent during the test. How much this can affect operation, I dunno; Ford likely compensated for buildup, the plate moves less distance during the test, but TPS still gives suitable answer for movement. Maybe. Mine is recommended "Do Not Clean".
Guess you know how/why I learned all this **** about DBW, right? [IMG class=inlineimg]/forums/images/AllFordMustangs-vbtoucan/smilies/tango_face_wink.png[/IMG]