[jzurheide]

Hi. I had a problem the other day with my Crosstrek and after having it at the dealer all day yesterday, I still don't have any answers. Hoping someone here might have some ideas. I have a 2015 Crosstrek with the standard engine (not hybrid). It has about 80K miles on it and I have not had any previous major issues with the car.
We were driving from Chicago to St. Louis towing a small camper trailer (about 1200lbs loaded). The car was also loaded up with luggage and passengers but I still don't think we were above the GVWR.
About 250 miles into the trip, the RPMs start going up and down randomly (I was using cruise control), then the car begins slowing. I got to the side of the highway and it died and wouldn't start again. When I tried starting the car it would crank and then seem like it started (I could take my hand off the key) but then it would shudder, shaking the car, and die. We disconnected the trailer and tried starting again but it still did the same thing. After about 45 minutes we tried starting it again and it started fine. Someone else towed the camper for us and we made it the remaining 50 miles to STL fine.
After having it at the dealer all day yesterday they said they couldn't find anything wrong with it....no codes and everything looks like it's working properly. They tried to blame it on the trailer electrical system. We have a Subaru hitch and harness but the connecter is a bit dirty. The trailer has a brake controller mounted on the trailer that runs off the wire that powers the lights. The said that the trailer could have been drawing too much power which caused the car to shut down. However, that doesn't really make sense to me or anyone I have talked to about the trailer components.
Other options we discussed was the transmission overheating due to the towing but there was no indication of that on the scan and I didn't see a light or have any of the usual symptoms. When I mentioned the shuddering, the mechanic mentioned the fuel system but said that there should have been a code. We've done some research and it looks like there was a fuel pump recall recently but it didn't cover our year. We were low on gas at the time (about 1/4 tank left) which the mechanic said could cause and issue if the fuel system was already having problems.
Anyone have anything similar happen or ideas for what it could be? We basically left the dealer with a recommendation to stop towing and make sure we have AAA! Thanks!

 

[Cogen Man]

Just a thought here. Check your battery connections. Espectially the ground from the negative to the frame of the car. This happened to someone I know not with a Subaru but to a VW Golf. The ground to the frame was loose and corroded and his car would die while driving for no apparent reason. Just a thought.

 

[AFCMRET]

+1 for checking ground connection points...clean the trailer connector-check for the green death (corrosion) on the connections and up the wire loom.
IF the trailer was drawing so much power it scavenged the battery to the point of shutdown there is something amiss with the charging system. You should have gotten a charge warning light. See 1st item.
Fuel pump could cause a erratic/hard to diagnose event. Especially if it is intermittent. Lower fuel levels can expose the pump and thus not get the benefit of submerged cooling and then a overheat/low output to cause a fuel starvation event.

 

[243winxb]

The fact that engine run ok after a 45 minute cool down, seems high heat was issue.

Fuel system vapor lock. Caused by high heat. Towing & carring extra weight greatly increases strain on the engine.

An electric fuel pump should not allow vapor lock to happen? Check fuel pump output pressure.

Change any, all fuel filters. Hows the air cleaner?

 

[243winxb]

Might try- Wrap fuel line with insulation to prevent vapor lock, near the engine. Looks like its for sale online.

Back in the 1960, we wrapped the fuel line near the engine with Heavy Duty Reynolds Wrap, for drag racing. Some even had "Cool Boxes". We run the fuel line into a metal box & dumped ice in it. Cool fuel & air allows more to enter piston chamber, go faster.

2 electric fuel pumps were used. 1 at tank, another closer to engine.

A spray bottle of water, to mist the engine, was also used between runs.