Help: Car Randomly Dies...

[Stanky Leg]

My 1991 Legacy seems to die randomly while driving. It has a TD-04, top mount intercooler, and a PP6 (the PP6 is wired in, but not tuned, nor functioning). Typically, I am driving and it will run fine, then suddenly buck a few times (seemingly pulling fuel) and then simply shuts off, leaving me with a fully lit dash. This all began last night, as I drove to a friends in the heavy snow, causing me to wonder if something has been simply knocked loose. However, a couple days ago I had Seafoamed the car, changed the oil, and noticed a hose was not connected at all (a tiny vacuum line). After having done this I flashed the ECU, and have done so twice since. I am at a loss as to what could be wrong! Any help or advice would be greatly appreciated. Thanks!

[SILINC3R]

Sounds like my problem I had a week ago. Check that vacuum line. If you have a boost guage and you notice it not reading thqt is your problem. If that line is not hooked up it doesn't let the vehicle reading bar. Pressure or something like that and puts it in a limp mode and will hit a fuel cut if you push the pedal to hard. Check that line.

[jefferson]

I was thinking you might want to check the fuel pump.

Jeff

[turbo-baron]

I'm with Jefferson, More than likley the fuel pump. When it dies does it fire right back up again?

[Stanky Leg]

The car did start right back up again after dying.

Today I put in an STi fuel pump I got from a friend, which seems to have "solved" the problem more or less. It has been driving fine, but has since died on two occasions, whereas before it would die about every 1,000 feet. Any other ideas?

[BoostedSubie]

On my first legacy, i had a similar issue. It turned out to be the connector where the fuel pump pigtail plugs into the body harness (under the rear seat). It had accumilated some moisture in it and melted the plug. I just cut it out and hardwired it. Something to check.

[Stanky Leg]

On my first legacy, i had a similar issue. It turned out to be the connector where the fuel pump pigtail plugs into the body harness (under the rear seat). It had accumilated some moisture in it and melted the plug. I just cut it out and hardwired it. Something to check.

Thank you, I'll certainly give that a look. I was also suspecting the coilpack...?

[Stanky Leg]

So I believe I have solved the problem. I found a massive vacuum leak that had been avoiding my attention. Thanks for the advice and I'll alert if this doesn't solve the problem.

[SILINC3R]

So I was right

[Stanky Leg]

So I was right

Wellllllll, not quite. That vacuum leak was not caused by the hose that I had already fixed. This was a different line in a different place.

As for the car, it died again today... The search for vacuum leaks continues. I find it amazing all of this has gone wrong at once. Fuel pump, vacuum leak, another vacuum leak and now yet ANOTHER vacuum leak... Or at least that is what I think it is.

[Legacy777]

I know you probably won't like this answer, but I had similar issues where my car would buck very badly with the pp6 wired in, but not doing anything. Similar setup as what you have. Do you have the bypass connector that came with the pp6? If so, try installing that and see if the problem goes away. If it does, you've narrowed down the problem to the pp6. If the problem does not go away, I'd suggest looking at trying another MAF sensor.

[Stanky Leg]

I truly appreciate all of your help! The car seems to be fine now, thank god. I have a new MAF sensor in reserve and will certainly give it a try if a similar issue arrives.