GT-40 No Longer Dying

[Bill]

Help please. I have a 1996 Ski with the GT 40 motor and at various times it just dies. It seems more prone to happen when the motor is cool but it has died at operating temps as well. I have changed the fuel filters, checked the ground wires, cleaned the battery terminals, new key switch,etc. After it shuts down it will start right back up. It has never let me sit. I have noticed every once in while that the idle is not smooth. Not rough running--just up and down from 1200 to 800 rpm. I want to think it is something electrical. Any ideas?

Thanks

[skinautique]

Could be bad relays on the back of the engine or the computer itself. I would probably start there. I can try to help but it is always hard without hearing the engine. Good luck and keep us posted.

[tryan]

read some of the other threads on issues with the gt-40. you might clean your air idle control motor to get the idle stabilized and see if that cures the tendancy to die. from the seamaxx parts diagram, it looks like it is on the back side of the throttle body.

everyone with an efi motor should consider this as part of a normal maintenence/winterization routine.

[NautiqueJeff]

Could it possibly be a faulty kill switch? You know, that thing that we always clip to the driver before taking off down the lake? I had a somewhat similar problem with my '94, and we finally figured out that the kill switch was causing it.

[go46]

Tryan- Please expand on cleaning the air idle motor please.

Thanks

[Bill]

thanks for everything so far and i forgot to mention that i already did the kill switch thing. i will wait for the expanded post on the idle motor.

[tryan]

sorry go64, i got rid of my last fi 302 over 10 years ago. the idle control motor bleeds air under the throttle plate to control the idle speed made famous by the audi unitended acceleration fiasco.


the stepper motor controls the idle speed by varying an opening around the throttle plate. if the valve cannot operate smoothly, it will be slow and over or under compensate resulting in an unsteady idle.

it is possible for the motor to have other issues and/or vacume leaks. on a open loop fuel injection that can't maintain a steady idle, i would check the aic first.

[nms1991]

bill check your fuse holder near the battery for corrosion and check the battery clamps to see if they are cracked or the keep alive memory wire is tight (the fuse holder on the battery)

[Bill]

thanks for the info but have already done both of those things. has anyone had this type of problem because of water in the gas?

[skinautique]

You checked out the relays on the back of the engine? I have seen a MAP sensor go bad and it caused the GT40 to not run so hot. It was cracked.

[Bill]

GT 40 No longer dying

It appears as though i have gotten to the bottom. The only problem now is that i did so many things that may have fixed it that i can't point to just one thing causing the motor to just die. Oh well it runs fine and can now ski. Thanks for all the advice.

[newfoundskier]

How difficult is it to install a new map sensor? Where is it located on the GT-40?

[nms1991]

not very difficult it is on the port front of the engine upper intake manifold next to the coil held on by two 10 mm bolts a electrical connecter and a vacumme hose.