Hi, just did an auto box self diagnostic and it came up with a code , 3, throttle sensor disconnected/shorted. Now the car has a brand new TPS, which is set up correctly and reads the correct volts etc when closed, both cables seem well connected at the top end , does anybody know if there is a multiplug on the box and if so- where should I be looking for it, and are there any continuity tests I can do to try and trace the fault. Any help appreciated.Thanks in advance

Hi Kenny,

 

I would do an main ecu diag to confirm - http://www.ttzd.com/tech/diagnostictech.html

 

And here's the throttle sensor circuit check from the manual - http://www.300zx.co.uk/cgi-bin/manual.cgi?list=at&dir=&config=&refresh=&direction=forward&scale=0&cycle=off&slide=53&design=default&total=194

 

Vijay

Ok - main ECU check had no codes, I was thinking that the connecter at the gearbox end maybe disconnected.

 

symptoms that caused me to do the diagnostic in the first place were stalling when slowing to a stop when vehicle is cold, rpm drops from 7-850 to 50 rpm, and either stalls or picks back up. as if the box is dragging or the engine stumbling. when the vehicle warms up the problem is no where near so severe, and after about 2 miles of driving is virtually undetectable. If in heavy traffic it seems to stumble at times but not consistantly(. If the grey plug on the TPS is disconnected the car reverts to backup idle, if the black connecter is disconnected from the TPS it makes little or no difference, if both are disconnected the idle speed rises to about 1000 rpm . The TPS voltage is set to 0.45volts when closed.

Hi Kenny,

 

Have you checked the pins on the auto ecu as described in that second link?

 

Vijay

Not going to be able to check that until I get home. And locate the box ECU.

as soon as I get back I intend to .

Ill keep you posted.

cheers

Ok, idi the pin check as described in the manual, unfortunatley my multimeter has gone a bit nuts as I dropped it on the way over to the car :mac1: . However it got a reading of 0.35 volts when throttle pedal untouched, and increased to about 3.5 volts when depressed slowly, but they may not be accurate figures, sometimes it read more sometimes less. but it is reading .

Ive done two things now , which seem to have helped, I cleaned the Air Bypass valve and refitted it, then bumped the idle speed by 100-150 rpm, the engine now fast idles when cold , and although there is still a stumbling/ missing when cold, as soon as it reaches operating temp this dissapears totally. took it up to the Jap performance sunday in Hickstead yesterday ( the only Z that turned up!) and it ran very well, almost perfect. However I had to do a sharp stop today and it stalled ( and there was me thinking I had it sussed). Any other suggestions folks? auto ECU still showing fault code three. :confused:

LOL!! if you get to the bottom of this theres a guy in broadstairs with the same fault!!

 

i had a look & tested/swapped the TPS.

 

i suspect its a fault in either the gearbox or engine ECU passing/recieving the incorrect info

 

try & find someone local who you can swap the ecu's over with