95 SHO ATX dies when warm.....

[Indecline]

ok here is the deal i went thru all the forums first to see if anyone had similar problems and none of you did

i checked the codes and the only one i get is 538

here is what it is doing

when i start it after it has been sitting for awhile like overnight or a couple hours etc... it warms up like normal, then when it reaches or almost reaches normal running temp it dies the engine just cuts out. If i wait for like 30 seconds to a minute it will start right up and have no problems til i park it again for an extended period of time. This is not fun to have going on when going down the Highway.

60,000 mile was done about 3 weeks ago by dealership
and i have had them check on this problem repeatedly to no avail.

any help would be appreciated

 

[yamahaSHO]

Did they replace the CPS? If so, is it gapped correctly?

 

[Indecline]

they did not replace the CPS...
I just replaced the coolant temperature sensor and that did not help

could it be something else?

Throttle body?

 

[yamahaSHO]

A 538 code means you either did not "goose" the throttle when you were supposed to, or you did not press the pedal far enough.

I sounds like it could very well be your CPS. Have you had a water pumpe leak?

Does your tach do funny things? If not, I would replace the CPS.

The ECT won't cause the car to do this. A faulty ECT will cause the car to run very rich and delay the fan turn on. Ultimately giving you a very warm running car.

I highly doubt it is your TPS(throttle position sensor), try running the codes again and make sure you goose the throttle this time.

 

[sdpatt]

The 538 code would be generated only during the key on engine running (KOER) test. Have you run the key on engine off (KOEO) test to retrieve the memory codes? Those are the codes you are looking for.

Watch the tachometer the next time it happens. Immediately after the engine dies, if the tach drops and stays at zero, there is no signal from the CPS. Even with the ATX the engine will be free wheeling a bit and the tach should show some engine rotation.

Another possibility is the fuel pump cutting out. After the engine dies, turn the ignition key to ON, but don't turn it all the way to START. You should be able to hear the fuel pump spin for about one second before it shuts off. The noise should be a steady, high pitched whine. If the pump doesn't run or has a struggling, surging sound than the pump may be weak and dying.

You can also have the fuel pressure monitored while the engine warms up to see if the pressure drops before the engine quits.