vue = 2003= AWD 3.0 l V6. heres the problem= Car starts & runs excellent! -Then all of a sudden- engine dies. Doesn't run eratic/ stumble -just dies =like key is turned off!! Sometimes will restart-immediately -yet other times - doesnt start for a while. Crank pos. sensor has been replaced!! I have checked with a code reader several times when this happens- NEVER any Codes stored. I have also tried disconecting the battery =Negative cable -waiting a few mins- still no start!! Let it cool - then will start , run great till problem occurs again. Any Suggestions. I have not at present checked for spark when dead. Whats the possibilitys of problems causing this.? Help is ful;ly apprecieated, Thanx.

 

I know absolutely NOTHING about the 3.0 V-6 Saturn Vue. All I know is that I don't want one. Maybe a cam sensor?

 

Go have charging system load tested at Autozone or similar -- it's free.

Tell them your issue is intermittent and to please run the test 3 times.

Also, check for spark and fuel at fuel rail when dead

 

Heres the problem with that?? I can do all except getting to autozone- car dies & the restarts in a short while. I can & will do the fuel & spark checks today -i have all the test equip.here. Car only does this when warm us - scans say 183 degrees always. im thinking = computer, or a circuit breaker in electrical?? As sure seems heat (elect.) related.?? Thanx for the suggestions.

 

Hook it to a scanner that will give you data and see which sensor quits when hot. It needs cam and crank sync to run either one will make it quit.

 

the scanner says the temperature is 183 deg ALL the time, or once the temp gets to 183 deg, the engine dies....?????

Ahhh V6....cam sensor too (living in the mental world of S cars has its disadvantages---though I do try to get out some)

 

Thanx derf & all- The temp goes up as should-fan comes on @ around 200F. all works as should. Onlive scan = nothing seems wrong at all. even when dead. Just fuel pressure is = 0 (none) when engine is dead! I will measure fuel pressure today when running & again when dead to see if it could be a fuel pump problem.

 

Does this car have a VAT system? It could be a heat soak issue in regards to the Vehicle Anti Theft system.

 

Good thinking yet has no VAT system.I did order a used computer to try today -so we will see.Thanx

 

[COMPLETELY REVISED RESPONSE]
Can't believe I missed that. Just because your engine stops does NOT mean your fuel pressure goes to zero instantaneously.
There should still be fuel pressure in the system--when you first turn the key to run and the fuel pump primes the system, it's not priming from zero b/v/c the system should be holding pressure pretty well but not perfectly constant.

The ONLY situation in which I can see the fuel pressure go instantaneously to zero after engine DIES is if the fuel pump stops pumping. In this situation, the remaining fuel pressure will push the remaining gas up to the engine, it will burn until no gas is left----THEN 0 fuel pressure-->stall. Can't restart because literally no fuel present at rail.

Since this seems heat related, I'm gong to say there are two ways (well, 3) in which this can occur:
1) Defective fuel pump relay -- works fine until it hits a certain temp at which time it overheats, contacts open, the fuel pump shuts down, and the scenario described above occurs

2) Defective Fuel pump works fine until it overheats (from self generated heat) and shuts down. Might not blow the fuse b c i is not a failure from too much current draw.

3) Wiring issues--most likely at the terminals if the fuel pump relay either in the relay pin slots or connections to the underside of the fuse box, which, along w everything under the hood, is heating up and expanding, which could cause a [broken wire that is still making contact w the bottom of the pin] to separate and break the electrical connection.
_____________________
a) Check Fuel Pump Relay Normally I would say check for wiring issues 1st; but in this case, testing the fuel pump relay by swapping in the windshield washer relay (or whichever one is identical under there) for the fuel relay. If the original relay was he culprit, then the assumed good one will function with no issues and you will have solved your issue. I'd put the window washer relay back and get the new one for the fuel pump.

b)Check Fuel Pump Personally I've never done so, but based on the presence of the relay there should be dedicated power and ground runs to the pump from the relay pins. Monitor the voltage across the pins WHILE CONNECTED to the fuel pump. When the engine stalls, if he here is no longer 12V across those, the pump may have entered a failure mode that breaks the circuit and therefore no V should be measured. Having never done this, I'm pretty sure this is a valid test. NOTE: MUST be performed with known good fuel pump relay

c)Wiring UHJB and at fuel pump. Scorched terminals and wires, melted plastic, rusty contacts from interaction with moisture.....but you'll know which wires to look at

Ok that's all I have.

My money is on the fuel pump relay