Jump to content
Ultimate Subaru Message Board

91 Legacy wagon with acceleration issues, currently won't start. Is this a bad fuel pump?

Recommended Posts

I have a 91 Legacy wagon which has been having startup issues on occasion. I usually manage to get it started by attempting to start it with my foot on the gas pedal, but when it starts it usually sputters for awhile and often turns off again. When I just turn the key in the ignition prior to starting it, I always hear a humming sound, and I wonder if that sound is related to or indicates the fuel pump may be going bad? Also whenever I drive the car it often has trouble accelerating especially after I've stopped at a stoplight. I just had the oil changed and had the fuel filter replaced and fuel system cleaned at the shop 3 days ago, and they also did diagnostics. But they didn't say anything about a faulty fuel pump, or maybe they didn't even consider it. Either way this all cost me over $300 already, so I just wonder if anyone has any ideas or suggestions before I spend any more money. Thank you all.

Link to comment
Share on other sites

If the pump is louder than normal, it's probably failing (or you have a ton of dirt clogging the sock). Often, the engine will "run", but only for so long and with obvious performance issues. Would be good to know what the fuel pressure is.



Good news is the fuel pump isn't that hard to do (dunno if you have under the back seat access or not) and you can get them at a good price from Rock Auto. DIY will save you a ton of money. Do NOT use a steel punch to loosen the ring as that can create a spark. 

Link to comment
Share on other sites

You'll always hear a hum from the fuel pump as it primes the fuel system when you turn the key on. Should last about 2-3 seconds and then stop.


If it starts with the pedal on the floor that indicates the engine is flooded with too much fuel. This is commonly due to a bad coolant temp sensor. Usualy less than $20 for a replacement, and fairly easy to change on your own. Can also cause driveability problems such as stumbling and hesitation.


Also be sure to check the vacuum hoses and the hoses that attach to the intake tube. I know it may look like there's a maze of hoses on the engine, but these really aren't that complicated if you take a little time to follow where each one goes and what it attaches to.

Check all of the small vacuum hoses for any breaks or split ends. If you find any that are loose or broken, they need to be replaced and properly connected.

  • Like 1
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


  • Create New...