How can I adjust the Throttle Position Sensor on my 3.5

[tram]

To set throttle switch:

Loosen both set screws. Take note of the little gradient scale by the screws.

Rotate your switch clockwise to the stop.

Turn key on

Rotate your switch the other way until you hear the injectors click.

Go one more gradient mark past the click

Tighten the screws.

[werminghausen]

Originally Posted by Frank Reiner

Re: Posts #13 & 14

You have both observed proper operation of the D-jet ECU in closed throttle coast-down. Fuel is cut off above ~ 1800rpm when closed throttle is sensed. Injector pulses are restored at ~ 1200rpm, or when the throttle is again opened. If a jerk is felt when pulses are restored, it is due to a leaking bypass air valve, or the ECU restoring the pulses at too low an RPM.

Thanks Frank
great information. some questions
What/where is the leaking bypass air valve on the 3.5?
If ECU is restoring pulses at too low rpm (below 1200 rpm) is there a way to correct? or is there nothing to adjust?
Martin

[Frank Reiner]

Actually there are two bypasses around the throttle plate; 1. the idle air screw, and 2. the auxiliary air valve which provides added air during warmup. As you know, the throttle plate stop is to be adjusted so that the plate is just free of sticking in the bore when the throttle is closed. All idle air is to be supplied via the idle air screw. It is the aux air valve that I had in mind when I referred to "bypass air". Anything that causes a leak of false air into the intake manifold will result in manifold pressure that is higher than the ECU is programed for, and subsequently a greater power output when the injector pulses are restored. Another source of false air is the seals between the upper and lower sections of the intake manifold. In fact, any hoses and seals that are connected to the manifold are suspects until proven otherwise.

As to the "pulse on" RPM, that is part of the programming of the ECU; I do not know of any way to alter that.

[Graham]

Originally Posted by Frank Reiner

Re: Posts #13 & 14

You have both observed proper operation of the D-jet ECU in closed throttle coast-down. Fuel is cut off above ~ 1800rpm when closed throttle is sensed. Injector pulses are restored at ~ 1200rpm, or when the throttle is again opened. If a jerk is felt when pulses are restored, it is due to a leaking bypass air valve, or the ECU restoring the pulses at too low an RPM.

Frank is right.

I too have a wide band AFR meter. When driving, if you take your foot off pedal, AFR swings immediately to full scale lean. As Frank said, it is designed to do that on most (but perhaps not all) DJets. Fuel is reinstated at some lower rpm and you see the AFR move back up to somewhere around 14.