Re: 1992 V6sei auto gearbox repair
Posted: Sat Mar 09, 2019 10:03 am
Idle speed regulation is achieved by the IC valve which is controled by the engine ECU, the ECU is (on early cars) supplied with gear selector information to determind if the gearbox is in a Neutral or Drive state, later auto ECU's and all manuals seem to just assume gear selector state is always Drive,i am not sure why later ECU's would be setup to do this or what purpose this information was supplied to the ECU for but i would imagine it was something to do with the fuel cutoff on a trailing throttle and possibly part of the A/C clutch control strategy.
The gear selector switch provides a signal to the start inhibitor relay, gear selector display, reverse light switch and Engine ECU.
The ECU fitted to my car assumes Drive all the time, the previous one showed Nuetral or Drive selection but provided a jerky transition on the fuel cut threshold, a third ECU i tried would read the info backwards so the Lexia would show it was in Drive when the gear selector was in N or P and Neutral when D or R was selected, this ECU made the engine stall after snapping the t5hrottle open in Neutral, it struggled to catch the idle speed after being revved.
Either way, the gear selector switch will not be your problem, a total loss of Drive will be a mechanical issue with the gearbox, i have read before that many valves, if stuck, will result in a no drive situation, but equally, it could be a Torque converter or hydraulic pressure issue, for the sake of a £10 pressure gauge and a few more £ worth of fittings to connect the gauge to the test ports i would seriously be looking to do a pressure test, rising idle speed when selecting a gear, to me, sounds like a mechanical failure, why is the box offering less of a load on the engine when you try to put it in gear?
D
The gear selector switch provides a signal to the start inhibitor relay, gear selector display, reverse light switch and Engine ECU.
The ECU fitted to my car assumes Drive all the time, the previous one showed Nuetral or Drive selection but provided a jerky transition on the fuel cut threshold, a third ECU i tried would read the info backwards so the Lexia would show it was in Drive when the gear selector was in N or P and Neutral when D or R was selected, this ECU made the engine stall after snapping the t5hrottle open in Neutral, it struggled to catch the idle speed after being revved.
Either way, the gear selector switch will not be your problem, a total loss of Drive will be a mechanical issue with the gearbox, i have read before that many valves, if stuck, will result in a no drive situation, but equally, it could be a Torque converter or hydraulic pressure issue, for the sake of a £10 pressure gauge and a few more £ worth of fittings to connect the gauge to the test ports i would seriously be looking to do a pressure test, rising idle speed when selecting a gear, to me, sounds like a mechanical failure, why is the box offering less of a load on the engine when you try to put it in gear?
D