my 240 is pissing me off

[89 coupe]

ok so ive been trying to solve an idle problem. i used to have a fluctuating idle but i solved that with a new tps. now it just a high idle. i adjusted it to specs and it was runing at a normal idle. turn the car off and then back on and it shoots right back up to 1800-2000rpm. i checked my timing and thats ok. i tested my coolant temp sensor and its fine. i pulled codes from the ecu and i got a 55 so no problems that its detecting but there is obviously one present. now my speed sensor is totally out of wack since it says im going 90 km when idleing at 1800rpm. so we just disconnect that thinking it might do something and it was idling at 750rmp. turn it of and back on again. high idle at start up but thats normal then it drops back down to 750rpm. plug the speed sensor back in start it up and back to high idle. but what does the speed sensor have to do with your idle? its just there to tell you how fast your going.

[GODCHSR]

You posted this question twice in the same day... not ok.

Also your title is indescriptive.

[Bongpain]

NotesClassification:EC91-001

Reference:NTB91-022

Date:March 7, 1991

240SX IDLE FLUCTUATIONAPPLIED VEHICLE(S):1989-90 240SX (13)

APPLIED VIN(S):Federal - JN1HS34P*LW 109709- JN1HS36P*LW 153129Calif. - All 89-90

APPLIED DATE(S):Federal - June 8, 1990Calif. - All 89-90

SERVICE INFORMATION

Some 1989-90 240SX vehicles produced before the applied date may experience idle fluctuation when coming to a stop (engine warm) or after a warm restart. If this occurs, perform the following service procedure.

SERVICE PROCEDURE1. Verify proper adjustment of the engine control components and idle speed according to Service Manual specifications and adjustment procedures.

2. If these components are within specification and self diagnosis indicates code 55 (all clear) in mode III, replace the ECU with the new part listed below.

[Wc240]

gotta love ASSIST

[lazerusthedonutking]

try adjusting your throttle, or replace the crank position sensor. sensors suck, they can cause all kinds of trouble when they fail. was the tps brand new or from a junk yard? if it's used, get a new one. and if all else fails, kas are pretty cheap, just buy another one haha jk

[Oneandonly212003]

it might sound weard but on my brothers 240 it had a wacum leack on the hose that runs to the brake boster after we replaced it it was ok

[theengineguy]

that service bullitin says it all... if you got high idle and the computer is not trying to correct it ... and sees nothing wrong with it... its not thinking right... vaccum leak would produce a lean or fuel at max limit code and would not be intermitant. replace the ecu