No power to motor

subaru
outback

#1

I have a Subaru Outback AT with nearly 240k. There are two problems that I have been having and I’m unsure whether or not they are at all related. The first is simply that the car wont start sometimes, it has only been happenng about every couple of weeks without any sort of pattern for the past year or so. All the lights work when the key is turned and the starter turns over but the motor won"t start. Some times it starts the second turn of the key–sometimes the 100th.

The second problem is that sometimes when accelerating from a stop ( usually pulling out of a parking spot) there is no power to the motor. I hit the gas pedal and for some reason it feels like there is something restricting power to the motor. I take my foot off the pedal and reapply it and susualy on the second or third try something catches and my car begins to move again.

Any help?


#2

I wish this wasn’t so intermittent, because that can make it hard to chase down. The next time you can’t get the car started, take the gas cap off and try to start it then. If it starts right up, your tank probably isn’t venting properly. This can also cause the symptoms you experience when trying to accelerate.


#3

Check engine light?
Any codes?

I used to have '96 Legacy Wagon with 125K miles, that thing had troubles starting and getting from the stop, which were cured by a new set of GOOD high-voltage wires. For my case, I found correlation of my issues to wet or cold weather and replaced wires with some cheap ones first, it got better, but still not to the “purring kitty” state, so I swallowed an extra cost of OEM wires and it worked great.

My another '03 Outback with 90K miles on it developed trouble getting from the stop, although not as profound as yours, but probably due to the fact it was stick-shift and I could rev it up to get going. It was cured by cleaning throttle body and idle valve, expense was pretty much to get hands dirty and spend few bucks on carburetor cleaner can.

No guarantee it is applicable to your case, but give us more info on prior maintenance/repairs.


#4

In addition to cleaning the throttle body and the IAC, I think there is a possibility that the TPS is problematic.
Do those cleanings first, and if they don’t help, then I would suggest focusing on the TPS.


#5

Yes, exactly. I had the same issue with my 2011 Outback (only 37,000 miles) not starting whenever it was not in the mood. Then it started stalling right in middle of driving. Three times I had it taken to the Subaru service department. They kept telling me it was fine. I left the car there for several days three times and they kept saying it started fine for them and the diagnostic computer said there was nothing wrong with the car. The owner of the dealership told me he was selling 300 Subarus a month, implying that my problem was imaginary or I was lying. I began videoing the issue with my i-Phone. With the last AAA pickup I told the driver to please go into the service department and testify that the car would not start. Finally, after much research, I took the car into Service and gave them a list of five things I wanted them to look at. I insisted they not connect the car to their diagnostic computer, which was clearly not finding the problem. I suggested they give the car to the oldest mechanic in the shop. One who would listen and look and bypass the computer.
The car was ready for me to pick up one day later. The guilty component was the crank position sensor. When I was young and worked on cars that made sense and were service engineered, we didn’t have a crank positions sensor. Technology is great, but sometimes it gets beyond us, and we can’t figure it out. It took the Subaru service dept five weeks to fix my car. My wife and I cancelled a vacation and I was unable to use the car for anything more than a walkable distance from my home. I think Subaru is so reliable, or has the rep for being so, that they freak out and don’t know what to do when something malfunctions and the diagnostic computer can’t figure it out.


#6

Yup . . . you have to be able to think outside of the box. And don’t let no codes and no check engine light limit your diagnosis.

Probably 1/2 or more of the faulty crankshaft position sensors I’ve replaced never threw a code, and the check engine light was not lit. Yet the car would not start, stall, or both. And that’s a general observation for cars and trucks in general, I don’t even work on Subarus.


#7

Do you think these sensors degrade over time or is it a manufacturing defect?

I’m asking actually having my 2006 Pathfinder with 154K miles in mind… is it something to replace preemptively?


#8

It’s not a manufacturing defect, it’s just wear and tear. If you’re lucky, your engine will never need the sensor replaced, but if it does, at its age and mileage, it isn’t a sign of some conspiracy, bad parts, etc.


#9

I’ve checked on WikiPedia, it looks like some sensors are simply inductive, others are using Hall Effect, some are even optical.

Looks like mine is “overly smart”: http://www.rockauto.com/en/moreinfo.php?pk=1353376&cc=1433013&jsn=394&jsn=394 and integrates A/D and some pre-processing circuitry, but it is inductive type, so unlikely will degrade per se, only if electronic part fails.


#10

I would leave your sensor alone, unless/until you start experiencing problems


#11

agree, it looks to be unlikely and not directly connected to mileage