I replaced the Throttle Position Sensor (TPS) when I reinstalled my engine, so didn't bother to check it. However, since I've bee getting noise and vibration coming off the throttle, I've been reviewing anything and everything I can think of before pulling the tranny. Going over what the various sensors do in the 'Online Toyota Course' (a great, free reference website I recommend to all - easy to understand and a great partner to the BGB; the function behind the parts) I read this about the TPS: "All throttle sensors, regardless of design, supply the ECU with vital information about idle status and driver demand. This information is used by the ECU to make judgments about power enrichment, deceleration fuel cut-off, idle stability, and spark advance angle correction." Although I know rechecking timing is standard after installing a new engine, I was surprised to find it off by 5 degrees when I'd made damn sure it was 100% perfect when I reassembled everything. I'm also getting some idle instability (not holding 750 RPM) and roughness when perfectly still at 750 PRM. However, it was the deceleration fuel cut-off that really caught my attention. My 'tranny noise' is most prominent coming off the throttle. I wonder if I'm getting too much fuel continuing to come through the system. I gotta do my 500-mile post engine install oil job today (when it's 106 degrees out there - ug) so thought I'd run through the BGB tests on the TPS. Thoughts? Experiences? Thanks.
a tps is simply a potentiometer, or a variable resistor. just check the resistance of each of the pathways according to the book. and you will have your answer.
Yeah, that's on the list along with a bunch of other sensors, sending units, VSVs (etc) until I lick this A/F issue. Since engine internals are all brand new and top and bottom machined, I've gotta assume my problem is outside the head and block - and because I'd be bummin' huge if something was still wrong in there...!
With my old TPS, I did what the BGB said to do about testing the various electrical contacts with different thickness gauges between throttle stop screw and contact plate, but that was to determine it was bad. I just installed the new one. I recall something about adjusting the play in the screw slots, but with so many bad readings off the car, I just tossed the old one thinking there was no amount of fine tuning that would correct it. I assumed a new one should not have any such issues - wrong assumption?
.60 mm gauge and IDL to E2 terminal ohmeter check it is. Thanks. On another note, I'm replacing the hoses on the idle air control valve with the new IACV. One is carrying coolant, the other is carrying vacuum (a larger hose than all the other more standard vacuum lines) called the Air Auxillary Hose. Do you know the sizes I need for each? I tried ordering the actual parts from Toyota, but they are no longer available, so I need to get the right material hose in the correct ID/OD and cut it to length. Thanks.
