I am trying to fix my stepson's 2002 Saturn Vue with 3.0 V6 engine. It starts and runs fine when cold. Once it warms up fully, it will sometimes die abruptly with no warning, and will not re-start. Sometimes, but not every time, it will not even turn over. After about 15 or more minutes, it will start up again like nothing happened. BTW, the battery is new, and when it does turn over, it does so briskly.

 

How many miles are on it? Sounds to me like the starter is taking a dump on you. Could either be the bendix is weak or perhaps the armature is swelling and binding and then when it cools off, it spins again. Try tapping the starter with a hammer the next time it happens and see if it cranks.

 

Rube's got the starter angle covered.


But why does it just stop?


Check engine light on? Any codes? If light is on, go to Autozone or similar and have codes read for free. Please post them as Pxxxx where the x's are numbers.


I have an educated guess but I need to know if there are any codes present first

 

Codes are P0171 and P0174 (lean mixture), but only occur after driving at highway speeds. I had just changed the fuel filter and was testing when the other problem occurred (sudden death). I don't think the two problems are related. Personally, I think it's electrical.

 

1) Have you checked key on/engine off and idle fuel pressure vs specs?
IF for some reason the filter is defective OR if the fuel pump is weak, you should get a hint of it this way.

Also, if the fuel pressure regulator (I'm assuming it is inside the fuel filter) is defective, it may momentarily drop the flow to 0 long enough to stall the car.
Additionally, too low a flow through the filter could technically lead to a lean condition as the requested fuel is just not being supplied fast enough.

2)Did you have to remove the MAF and/or were you working anywhere near the MAF or throttle body during the time when you did the fuel filter replacement? (Sorry, not familiar w anatomy of the Vues)


Sounds like the engine is either receiving more intake air than it needs/wants or THINKS it is--or literally not enough fuel per unit time to meet demands

1) Check for vac leaks, specifically between the MAF sensor and the intake manifold. Specifically, the coupling betw the MAF sensor and the throttle actuator and the throttle gasket. Additional air getting sucked in through a vac leak will, if large enough, throw the lean code after the ECM tries to adjust the air/fuel mixture but reaches the max it is programmed to try.

2) If you cannot find any vac leaks, it may just be that the MAF sensor is providing bogus readings to the ECM, which in turn calcs bogus requested A/F mixes, which in turn cannot be met, which in turn throws the lean code.

REMOVE YOUR MAF FROM A COLD ENGINE and CLEAN inside of the MAF sensor with MAF sensor cleaner. I am not being sarcastic. There are specific cleaners made for cleaning MAFs. Follow directions on can and be sure to let dry before reinstallation. Good idea to change your air filter at the same time so the normal air intake path is "clean".

I'm leaning towards dirty MAF b/c of your comment that the codes don't pop till highway speed. Intake air is obviously the highest under those circumstances, so if the MAF is generating inaccurate readings, it is not at all implausible for the A/F mix to get messed up.

 

Dang it, derf! I think you may be on to something here.