Idle problem

[juiceman]

Had the TC on my Infiniti J30. The shop could never get the shift selector switch correct so I went under the car and found they had the shift locator switch loose. Fixed that and decided to check some other things like TPS (something they may have screwed with to adjust shifts) found the voltage at idle was under .30VdcAdjusted the voltage correctly and now the car idles at 1800 rpm when warmed and the IAC screw only makes the idle higher. I tried the WD40 deal (twinturbo.net) but this did not help

The TPS checked out electrically and I cannot get the connectors off the IAC unit to measure the resistance.

Any suggestions would be appreciated.

I did do a search but nothing related diretly

Thanks!

[Q451990]

Did you mark the TPS before moving it (or are there bolt marks)? I'd try moving it back. Also, make sure that the car is fully warmed up before adjusting anything related to the throttle body. The fast idle cams will set the TB open a bit, even in 90F ambient temperatures, so that'll throw off the base reading. On the Q not leaving some slack in the throttle cables can cause them to bind too... not sure on the J.

You may end up having the TPS reset by someone with a Consult.

Heath

[juiceman]

I have a meter to read voltage and it has the senistivity to read to enough places to accurately set the TPS Voltage

I canot tell where everything was due to the fact that it was originally moved by the yahoo that did my TC replacement and the voltage was off when I checked it

Car was warmed up to operating temp

I am going to try to reset the ecu to see if this helps any

[autotech43]

On a 93-J, what you need to be concerned with is the closed throttle circuit of the TPS. When the TPS is set correctly, the ECM will see the closed thottle at idle and off closed thottle when opening the throttle plate just off of idle. If the voltage is not within specifications after setting the closed throttle circuit, you need to replace the switch. That is why you are getting a high idle speed with no control, the ECM doesnt see closed thottle. The newer vehicles you can cycle the key switch and the ECM will learn closed thottle. If I remember there is a tech bulletin regarding an updated TPS depending on the year model. I will check at work and post results tomorrow.

[juiceman]

thanks for looking into it

I will investigate more on my end also

[juiceman]

Checked tps closed circuit. Works as expected. continuity when throttle closed and as soon as the tps is moved the the circuit opens

Finally got the aic connector off and set base idle and checked timing which was dead on. Had to use a eyeglass screw drive to get behind the clip and then hold with one finger to keep from flying

pulled battery terminal and let sit

Reconnected and started up and idle works great now.

Getting to things on this engine is tough and hard on the hands

[autotech43]

Glad you have the J in order juiceman. I'm looking at the tech bulletin and it is a revised procedure for setting the TPS but the J-30 does not apply. Bulletin ITB99-039b is discussing the closed thottle and feeler gauge method compared to the voltage procedure. What they are trying to say, the transmission control unit NEEDS to see the CLOSED thottle contacts(hard switch). If you look at the wiring schematic for the switch you can see the closed thottle wire (grey/blue stripe) is tied into the A/T control unit on pin #14. On the older consult we use to set the switch in the A/T mode and not the engine. If you had a manual transmission vehicle you could set the voltage wherever being there are no hard contact switch in the TPS. Things can get confusing if you dwell too much on it, keep it simple.